Hello,

I currently have as a workshop a cheap Yardmaster metal shed. With some modifications (interior boarding, polystyrene in the roof, etc) it's served me adequately for the last five years or so, but I really want to expand. In particular, I've just inherited a lovely old metalworking lathe, and there's no way I can set it up in the present space. So, time for a new shed.

What I have in mind is a timber structure - CLS frame, OSB interior lining, bit of rockwool between the studs, and feather-edge or possibly shiplap boards on the outside. Not sure of the roof, I guess a ridge with the shallowest pitch I can reasonably get away with (don't want anything too dominatingly high) and decent felt, but I'm open to ideas.

Seems simple enough, but then I heard about building regs. Apparently if you're over 15m^2 (which I will be, there's no point otherwise) and within a metre of the boundary (which I also will be - the garden is long but narrow and I really need to use the full width) then you're not allowed to build in wood under the BR exemption.

I did do some very rough costings for a blockwork shed or a prefab concrete a couple of years ago - I can't remember the details but I know it came out pretty pricey (then again, I haven't done even rough costs for timber, but it surely must be less). Also I'm a crappy bricklayer but I can shoot screws into softwood all day and come out with something reasonable at the end.. So I want to stick with the wooden structure if I can.

I've never done anything involving Building Regs before. If I talk to the guys at the council, are they likely to say "sure, go ahead", "Yes, but here are many onerous rules to follow", or a flat-out "no, you can't build it in wood because of the Great Fire of London"? This is in Southampton, if it matters. The proposed site is at the bottom of my garden, surrounded on all sides by the bottoms of other people's gardens in a typical Victorian semis layout.

Separately, assuming the wooden plan is a goer, I don't really know what to do about the floor. The current shed sits on a base of paving slabs laid by the previous owner, rather like a patio. I'm not sure exactly what's under them; the edges are raised about 6" with some cement visible so they're not just flat on the ground, but I don't know how much structure there is. This patio is too small for the new shed; I would need to either extend off one side of it or demolish it and start again. Such groundworks are complicated by the lack of access to the garden except through my hallway and living room.

I like the idea of a concrete floor, especially since I will be fitting the lathe and in due course probably a table saw and other large tools. I'm not quite sure how to start off a wooden building from that, but I'm sure there's a way. So smash up the existing plinth and use it as filler in a newly laid one? That's a lot of concrete though (5m x 7m x however thick). I'm imagining a great big hose being laid through the house from a lorry outside and pumping it in, but I've no idea if such a system even exists, let alone can be had at reasonable cost. The other option is to get a mixer (there's a guy at work hires out a Belle Minimix) and do it with barrows and shovels - I have no real experience, but I'm not sure that's sensible at this size.

So maybe I go for a suspended wooden floor after all - any advice on how best to do it? Bearing in mind one side of the shed would be over the existing slabs, and the other over what's currently grass. Frame and joists of treated 4" timbers and sturdy floorboards over?

Anyway, any advice on the job is welcome. And apologies for any Google wierdnesses in this post - I used to post to uk.d-i-y regularly years ago, but I no longer have a news account or a reader installed.

Cheers,

Pete

In article , Pete
scribeth thus
Hello,

I currently have as a workshop a cheap Yardmaster metal shed. With some
modifications (interior boarding, polystyrene in the roof, etc) it's served me
adequately for the last five years or so, but I really want to expand. In
particular, I've just inherited a lovely old metalworking lathe, and there's no
way I can set it up in the present space. So, time for a new shed.

What I have in mind is a timber structure - CLS frame, OSB interior lining, bit
of rockwool between the studs, and feather-edge or possibly shiplap boards on
the outside. Not sure of the roof, I guess a ridge with the shallowest pitch I
can reasonably get away with (don't want anything too dominatingly high) and
decent felt, but I'm open to ideas.

Seems simple enough, but then I heard about building regs. Apparently if you're
over 15m^2 (which I will be, there's no point otherwise) and within a metre of
the boundary (which I also will be - the garden is long but narrow and I really
need to use the full width) then you're not allowed to build in wood under the
BR exemption.

I did do some very rough costings for a blockwork shed or a prefab concrete a
couple of years ago - I can't remember the details but I know it came out pretty
pricey (then again, I haven't done even rough costs for timber, but it surely
must be less). Also I'm a crappy bricklayer but I can shoot screws into softwood
all day and come out with something reasonable at the end. So I want to stick
with the wooden structure if I can.

Can't see why not..

They make houses outa wood.

I've never done anything involving Building Regs before. If I talk to the guys
at the council, are they likely to say "sure, go ahead", "Yes, but here are many
onerous rules to follow", or a flat-out "no, you can't build it in wood because
of the Great Fire of London"? This is in Southampton, if it matters. The
proposed site is at the bottom of my garden, surrounded on all sides by the
bottoms of other people's gardens in a typical Victorian semis layout.


Ask them and whatever you do make sure that if they say all OK nothing
needed get it in writing!.

I think somewhere you might have planning permission issues but again
ask the council. Easier to ask then beg permission etc afterwards....

Separately, assuming the wooden plan is a goer, I don't really know what to do
about the floor. The current shed sits on a base of paving slabs laid by the
previous owner, rather like a patio. I'm not sure exactly what's under them; the
edges are raised about 6" with some cement visible so they're not just flat on
the ground, but I don't know how much structure there is. This patio is too
small for the new shed; I would need to either extend off one side of it or
demolish it and start again. Such groundworks are complicated by the lack of
access to the garden except through my hallway and living room.

I like the idea of a concrete floor, especially since I will be fitting the
lathe and in due course probably a table saw and other large tools. I'm not
quite sure how to start off a wooden building from that, but I'm sure there's a
way. So smash up the existing plinth and use it as filler in a newly laid one?
That's a lot of concrete though (5m x 7m x however thick).


I'm imagining a great
big hose being laid through the house from a lorry outside and pumping it in,
but I've no idea if such a system even exists, let alone can be had at
reasonable cost.

Yes they do but they can cost quite a bit;(..

The other option is to get a mixer (there's a guy at work hires
out a Belle Minimix) and do it with barrows and shovels - I have no real
experience, but I'm not sure that's sensible at this size.

If you have a friend or two who can be roped in then you can barrow it
if its not too far, did that the other year and it worked well a few
beer crates filled up was their reward. You can get small tracked
dumper's for hire might be another way, but god help if it packs up
while the mixer is waiting;!. Some people now do concrete in a mixer
that mixes it up from the raw ingredients on site, "volumetric" as per
here..


http://www.mickgeorge.com/services/concrete_supply/

So maybe I go for a suspended wooden floor after all - any advice on how best to
do it? Bearing in mind one side of the shed would be over the existing slabs,
and the other over what's currently grass. Frame and joists of treated 4"
timbers and sturdy floorboards over?

I'd make a decent job of it concrete is the best option I'd reckon..

Anyway, any advice on the job is welcome. And apologies for any Google
wierdnesses in this post - I used to post to uk.d-i-y regularly years ago, but I
no longer have a news account or a reader installed.

Cheers,

Pete

--
Tony Sayer

On 16/06/14 20:00, Pete wrote:
Hello,

I currently have as a workshop a cheap Yardmaster metal shed. With
some modifications (interior boarding, polystyrene in the roof, etc)
it's served me adequately for the last five years or so, but I really
want to expand. In particular, I've just inherited a lovely old
metalworking lathe, and there's no way I can set it up in the present
space. So, time for a new shed.

Building Control != Planning.

The Building Control Officer (BCO) is not there to stop you - in fact
you don't get his permission, you submit a notification along with a fee
describing what you are going to do.

However, he does need it done by the Approved Documents (google) before
he can give you a completion cert.

Your best bet would be to look on the council website (Borough or
District or City) for your area and see if you can find the BCO covering
you.

Then email him and ask if you can have a 10 minute meeting prior to
submitting a notice. If you take a sketch of your garden and what you'd
like to do, he should be happy to give you a quick "can't do that, but
you can do this" chat.

They are often very helpful (though that does vary by council).

Lots of people on here can help you with specifics.

Have a look here too:

http://www.planningportal.gov.uk/permission/

Do check that you can do what you want within permitted development or
you will have to deal with Planning too.

You could also be cheeky and make 2 15m2 buildings!

Tim

I was also thinking re the access, if its a semi, then surely there must be
a gap between his house and the next one, and a bit of sweet talking to a
neighbour and a promise of some cheap work being done, might make access
much easier.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"tony sayer" wrote in message
...
In article , Pete
scribeth thus
Hello,

I currently have as a workshop a cheap Yardmaster metal shed. With some
modifications (interior boarding, polystyrene in the roof, etc) it's
served me
adequately for the last five years or so, but I really want to expand. In
particular, I've just inherited a lovely old metalworking lathe, and
there's no
way I can set it up in the present space. So, time for a new shed.

What I have in mind is a timber structure - CLS frame, OSB interior
lining, bit
of rockwool between the studs, and feather-edge or possibly shiplap boards
on
the outside. Not sure of the roof, I guess a ridge with the shallowest
pitch I
can reasonably get away with (don't want anything too dominatingly high)
and
decent felt, but I'm open to ideas.

Seems simple enough, but then I heard about building regs. Apparently if
you're
over 15m^2 (which I will be, there's no point otherwise) and within a
metre of
the boundary (which I also will be - the garden is long but narrow and I
really
need to use the full width) then you're not allowed to build in wood under
the
BR exemption.

I did do some very rough costings for a blockwork shed or a prefab
concrete a
couple of years ago - I can't remember the details but I know it came out
pretty
pricey (then again, I haven't done even rough costs for timber, but it
surely
must be less). Also I'm a crappy bricklayer but I can shoot screws into
softwood
all day and come out with something reasonable at the end. So I want to
stick
with the wooden structure if I can.

Can't see why not..

They make houses outa wood.

I've never done anything involving Building Regs before. If I talk to the
guys
at the council, are they likely to say "sure, go ahead", "Yes, but here
are many
onerous rules to follow", or a flat-out "no, you can't build it in wood
because
of the Great Fire of London"? This is in Southampton, if it matters. The
proposed site is at the bottom of my garden, surrounded on all sides by
the
bottoms of other people's gardens in a typical Victorian semis layout.


Ask them and whatever you do make sure that if they say all OK nothing
needed get it in writing!.

I think somewhere you might have planning permission issues but again
ask the council. Easier to ask then beg permission etc afterwards....

Separately, assuming the wooden plan is a goer, I don't really know what
to do
about the floor. The current shed sits on a base of paving slabs laid by
the
previous owner, rather like a patio. I'm not sure exactly what's under
them; the
edges are raised about 6" with some cement visible so they're not just
flat on
the ground, but I don't know how much structure there is. This patio is
too
small for the new shed; I would need to either extend off one side of it
or
demolish it and start again. Such groundworks are complicated by the lack
of
access to the garden except through my hallway and living room.

I like the idea of a concrete floor, especially since I will be fitting
the
lathe and in due course probably a table saw and other large tools. I'm
not
quite sure how to start off a wooden building from that, but I'm sure
there's a
way. So smash up the existing plinth and use it as filler in a newly laid
one?
That's a lot of concrete though (5m x 7m x however thick).


I'm imagining a great
big hose being laid through the house from a lorry outside and pumping it
in,
but I've no idea if such a system even exists, let alone can be had at
reasonable cost.

Yes they do but they can cost quite a bit;(..

The other option is to get a mixer (there's a guy at work hires
out a Belle Minimix) and do it with barrows and shovels - I have no real
experience, but I'm not sure that's sensible at this size.

If you have a friend or two who can be roped in then you can barrow it
if its not too far, did that the other year and it worked well a few
beer crates filled up was their reward. You can get small tracked
dumper's for hire might be another way, but god help if it packs up
while the mixer is waiting;!. Some people now do concrete in a mixer
that mixes it up from the raw ingredients on site, "volumetric" as per
here..


http://www.mickgeorge.com/services/concrete_supply/

So maybe I go for a suspended wooden floor after all - any advice on how
best to
do it? Bearing in mind one side of the shed would be over the existing
slabs,
and the other over what's currently grass. Frame and joists of treated 4"
timbers and sturdy floorboards over?

I'd make a decent job of it concrete is the best option I'd reckon..

Anyway, any advice on the job is welcome. And apologies for any Google
wierdnesses in this post - I used to post to uk.d-i-y regularly years ago,
but I
no longer have a news account or a reader installed.

Cheers,

Pete

--
Tony Sayer

On Mon, 16 Jun 2014 12:00:03 -0700, Pete wrote:

Hello,

I currently have as a workshop a cheap Yardmaster metal shed. With some
modifications (interior boarding, polystyrene in the roof, etc) it's
served me adequately for the last five years or so, but I really want to
expand. In particular, I've just inherited a lovely old metalworking
lathe, and there's no way I can set it up in the present space. So, time
for a new shed.

What I have in mind is a timber structure - CLS frame, OSB interior
lining, bit of rockwool between the studs, and feather-edge or possibly
shiplap boards on the outside. Not sure of the roof, I guess a ridge
with the shallowest pitch I can reasonably get away with (don't want
anything too dominatingly high) and decent felt, but I'm open to ideas.

Seems simple enough, but then I heard about building regs. Apparently if
you're over 15m^2 (which I will be, there's no point otherwise) and
within a metre of the boundary (which I also will be - the garden is
long but narrow and I really need to use the full width) then you're not
allowed to build in wood under the BR exemption.

I did do some very rough costings for a blockwork shed or a prefab
concrete a couple of years ago - I can't remember the details but I know
it came out pretty pricey (then again, I haven't done even rough costs
for timber, but it surely must be less). Also I'm a crappy bricklayer
but I can shoot screws into softwood all day and come out with something
reasonable at the end. So I want to stick with the wooden structure if I
can.

I've never done anything involving Building Regs before. If I talk to
the guys at the council, are they likely to say "sure, go ahead", "Yes,
but here are many onerous rules to follow", or a flat-out "no, you can't
build it in wood because of the Great Fire of London"? This is in
Southampton, if it matters. The proposed site is at the bottom of my
garden, surrounded on all sides by the bottoms of other people's gardens
in a typical Victorian semis layout.

Separately, assuming the wooden plan is a goer, I don't really know what
to do about the floor. The current shed sits on a base of paving slabs
laid by the previous owner, rather like a patio. I'm not sure exactly
what's under them; the edges are raised about 6" with some cement
visible so they're not just flat on the ground, but I don't know how
much structure there is. This patio is too small for the new shed; I
would need to either extend off one side of it or demolish it and start
again. Such groundworks are complicated by the lack of access to the
garden except through my hallway and living room.

I like the idea of a concrete floor, especially since I will be fitting
the lathe and in due course probably a table saw and other large tools.
I'm not quite sure how to start off a wooden building from that, but I'm
sure there's a way. So smash up the existing plinth and use it as filler
in a newly laid one? That's a lot of concrete though (5m x 7m x however
thick). I'm imagining a great big hose being laid through the house from
a lorry outside and pumping it in, but I've no idea if such a system
even exists, let alone can be had at reasonable cost. The other option
is to get a mixer (there's a guy at work hires out a Belle Minimix) and
do it with barrows and shovels - I have no real experience, but I'm not
sure that's sensible at this size.

So maybe I go for a suspended wooden floor after all - any advice on how
best to do it? Bearing in mind one side of the shed would be over the
existing slabs, and the other over what's currently grass. Frame and
joists of treated 4" timbers and sturdy floorboards over?

Anyway, any advice on the job is welcome. And apologies for any Google
wierdnesses in this post - I used to post to uk.d-i-y regularly years
ago, but I no longer have a news account or a reader installed.

Cheers,

Pete

There were threads on this a few years back.

I think you may require planning, not just building regs, if you don't
conform to the requirements on the local government site. However it is a
while since I looked at it. Also, rules change constantly.
If it is only building regs then you probably don't want to meet all the
requirements for foundations and footings and damp proof and insulation
and......

See
http://www.planningportal.gov.uk/per.../outbuildings/

"Outbuildings are considered to be permitted development, not needing
planning permission, subject to the following limits and conditions:

No outbuilding on land forward of a wall forming the principal elevation.
Outbuildings and garages to be single storey with maximum eaves height of
2.5 metres and maximum overall height of four metres with a dual pitched
roof or three metres for any other roof.
**Maximum height of 2.5 metres in the case of a building, enclosure or
container within two metres of a boundary of the curtilage of the
dwellinghouse.**
No verandas, balconies or raised platforms.
No more than half the area of land around the "original house"* would be
covered by additions or other buildings."

So I think the planning governed the height - not more than 2.5 metres -
and the BR governed the materials

I went down a similar route and ended up building a shed out of blocks on
a concrete foundation with a flat metal roof because of the requirement
for the building to not be flammable if less than 2 metres from a boundary
IIRC. I think your felt roof would fail that test.

I wanted to be within 0.5m of the boundary, giving me roughly an extra 3
metres across the garden.

The maximum height requirement also prevent you from having a pitched roof
unless you are a dwarf, sink the building down into the ground, or have
very shallow walls and only stand up in the centre of the building.

Some of my discussions can be found if you search this group for Mother Of
All Sheds or MOAS.

I mixed the concrete for the base by hand using a mixer (just to prove I
could, really) and it took a day and a half. I also had a larger mixer on
hire than a Belle Minimix - I wouldn't recommend mixing for a large slab
with such a small mixer.

Probably the best way (as you are going to be running mixed concrete or
unmixed materials through the house anyway) is to get one of the on-site
mixer services.

We used this for the new slab when the house was extended at the back and
you can get an awful lot of concrete in during an hour if you have three
people running barrows and one person working the machine.

I compromised in several areas where I wouldn't if I was doing it again.
However the shed is still standing :-)

Cheers

Dave R


--
Windows 8.1 on PCSpecialist box

On Mon, 16 Jun 2014 12:00:03 -0700 (PDT), Pete wrote:

Seems simple enough, but then I heard about building regs. Apparently if you're over 15m^2
(which I will be, there's no point otherwise) and within a metre of the boundary (which I also
will be - the garden is long but narrow and I really need to use the full width) then you're
not allowed to build in wood under the BR exemption.

A structure meeting the fire regulations can still be in wood, just like
millions of UK houses built in the last 30 years or so. Line with plasterboard
and it's ok. Not ideal for a workshop but then you can fit OSB or ply over the
top and no one need know any different. The external cladding can be an issue.
A few treatments and processes can help but another way round it is to use this
stuff.

http://www.marleyeternit.co.uk/Facades.aspx

They will send out samples, It looks good a few years down the line and remains
maintenance free. It's easily cut with a sliding mitre saw. Fixing is just
like shiplap. Plenty of info online.

Not sure what you'd do for the roof, mine is a fibreglass flat 'green' roof so
while the vegetation might burn the roof won't.

For the main structure there is a bit of info on the TRADA website and their
handbook is ok but a bit pricey

http://www.trada.co.uk/

Also lots of downloadable info on the American Plywood Association site that is
free if you register

http://www.apawood.org/

One answer to the fire issue might be rendered SIP panels as used by Mark Rand
over in news:uk.rec.models.engineering

Construction was well documented on his website.

http://www.test-net.com/workshop/

Panels from http://siptec.com/ among others

I like the idea of a concrete floor, especially since I will be fitting the lathe and in due course probably a table saw and other large tools. I'm not quite sure how to start off a wooden building from that, but I'm sure there's a way. So smash up the existing plinth and use it as filler in a newly laid one? That's a lot of concrete though (5m x 7m x however thick). I'm imagining a great big hose being laid through the house from a lorry outside and pumping it in, but I've no idea if such a system even exists, let alone can be had at reasonable cost. The other option is to get a mixer (there's a guy at work hires out a Belle Minimix) and do it with barrows and shovels - I have no real experience, but I'm not sure that's sensible at this size.

Forget concrete unless you are using really heavy machinery or want to install
wet underfloor heating. Floors in 18mm OSB screwed to a rigid frame work fine
for most domestic and light industrial sized engineering machinery and things
are less likely to get damaged if you drop them. Lots of insulation and lots of
ventilation underneath are essential. Good garage floor paint, preferably as
light as you can helps loads.

--

Have a look at this site. Even if you are not interested in a log cabin type shed/workshop there is some useful info on Swift foundations if you intend having a wooden base/floor. Also look at the info on fire proofing wooden structures.

http://www.logcabins.co.uk

Richard

"Pete" wrote in message
...
Hello,

I currently have as a workshop a cheap Yardmaster metal shed. With some
modifications (interior boarding, polystyrene in the roof, etc) it's served
me adequately for the last five years or so, but I really want to expand. In
particular, I've just inherited a lovely old metalworking lathe, and there's
no way I can set it up in the present space. So, time for a new shed.

What I have in mind is a timber structure - CLS frame, OSB interior lining,
bit of rockwool between the studs, and feather-edge or possibly shiplap
boards on the outside. Not sure of the roof, I guess a ridge with the
shallowest pitch I can reasonably get away with (don't want anything too
dominatingly high) and decent felt, but I'm open to ideas.

Seems simple enough, but then I heard about building regs. Apparently if
you're over 15m^2 (which I will be, there's no point otherwise) and within a
metre of the boundary (which I also will be - the garden is long but narrow
and I really need to use the full width) then you're not allowed to build in
wood under the BR exemption.

I did do some very rough costings for a blockwork shed or a prefab concrete
a couple of years ago - I can't remember the details but I know it came out
pretty pricey (then again, I haven't done even rough costs for timber, but
it surely must be less). Also I'm a crappy bricklayer but I can shoot screws
into softwood all day and come out with something reasonable at the end. So
I want to stick with the wooden structure if I can.

I've never done anything involving Building Regs before. If I talk to the
guys at the council, are they likely to say "sure, go ahead", "Yes, but here
are many onerous rules to follow", or a flat-out "no, you can't build it in
wood because of the Great Fire of London"? This is in Southampton, if it
matters. The proposed site is at the bottom of my garden, surrounded on all
sides by the bottoms of other people's gardens in a typical Victorian semis
layout.

Separately, assuming the wooden plan is a goer, I don't really know what to
do about the floor. The current shed sits on a base of paving slabs laid by
the previous owner, rather like a patio. I'm not sure exactly what's under
them; the edges are raised about 6" with some cement visible so they're not
just flat on the ground, but I don't know how much structure there is. This
patio is too small for the new shed; I would need to either extend off one
side of it or demolish it and start again. Such groundworks are complicated
by the lack of access to the garden except through my hallway and living
room.

I like the idea of a concrete floor, especially since I will be fitting the
lathe and in due course probably a table saw and other large tools. I'm not
quite sure how to start off a wooden building from that, but I'm sure
there's a way. So smash up the existing plinth and use it as filler in a
newly laid one? That's a lot of concrete though (5m x 7m x however thick).
I'm imagining a great big hose being laid through the house from a lorry
outside and pumping it in, but I've no idea if such a system even exists,
let alone can be had at reasonable cost. The other option is to get a mixer
(there's a guy at work hires out a Belle Minimix) and do it with barrows and
shovels - I have no real experience, but I'm not sure that's sensible at
this size.

So maybe I go for a suspended wooden floor after all - any advice on how
best to do it? Bearing in mind one side of the shed would be over the
existing slabs, and the other over what's currently grass. Frame and joists
of treated 4" timbers and sturdy floorboards over?

Anyway, any advice on the job is welcome. And apologies for any Google
wierdnesses in this post - I used to post to uk.d-i-y regularly years ago,
but I no longer have a news account or a reader installed.

Cheers,

Pete

Make a timber frame and use box profile metal sheet for walls and roof.
Various grades of metal sheet available with different lifespans.
Can be plastic covered, lots of different colours.
Clear/translucent rooflights available too

Cheap lightweight and can be built as strong as you like.
Secured to timber with screw washers and seals (from same sourceas metal.
They will cut it to size for you.

Pete wrote:
Hello,

I currently have as a workshop a cheap Yardmaster metal shed. With some modifications (interior boarding, polystyrene in the roof, etc) it's served me adequately for the last five years or so, but I really want to expand. In particular, I've just inherited a lovely old metalworking lathe, and there's no way I can set it up in the present space. So, time for a new shed.

What I have in mind is a timber structure - CLS frame, OSB interior lining, bit of rockwool between the studs, and feather-edge or possibly shiplap boards on the outside. Not sure of the roof, I guess a ridge with the shallowest pitch I can reasonably get away with (don't want anything too dominatingly high) and decent felt, but I'm open to ideas.

Seems simple enough, but then I heard about building regs. Apparently if you're over 15m^2 (which I will be, there's no point otherwise) and within a metre of the boundary (which I also will be - the garden is long but narrow and I really need to use the full width) then you're not allowed to build in wood under the BR exemption.

I did do some very rough costings for a blockwork shed or a prefab concrete a couple of years ago - I can't remember the details but I know it came out pretty pricey (then again, I haven't done even rough costs for timber, but it surely must be less). Also I'm a crappy bricklayer but I can shoot screws into softwood all day and come out with something reasonable at the end. So I want to stick with the wooden structure if I can.

I've never done anything involving Building Regs before. If I talk to the guys at the council, are they likely to say "sure, go ahead", "Yes, but here are many onerous rules to follow", or a flat-out "no, you can't build it in wood because of the Great Fire of London"? This is in Southampton, if it matters. The proposed site is at the bottom of my garden, surrounded on all sides by the bottoms of other people's gardens in a typical Victorian semis layout.

Separately, assuming the wooden plan is a goer, I don't really know what to do about the floor. The current shed sits on a base of paving slabs laid by the previous owner, rather like a patio. I'm not sure exactly what's under them; the edges are raised about 6" with some cement visible so they're not just flat on the ground, but I don't know how much structure there is. This patio is too small for the new shed; I would need to either extend off one side of it or demolish it and start again. Such groundworks are complicated by the lack of access to the garden except through my hallway and living room.

I like the idea of a concrete floor, especially since I will be fitting the lathe and in due course probably a table saw and other large tools. I'm not quite sure how to start off a wooden building from that, but I'm sure there's a way. So smash up the existing plinth and use it as filler in a newly laid one? That's a lot of concrete though (5m x 7m x however thick). I'm imagining a great big hose being laid through the house from a lorry outside and pumping it in, but I've no idea if such a system even exists, let alone can be had at reasonable cost. The other option is to get a mixer (there's a guy at work hires out a Belle Minimix) and do it with barrows and shovels - I have no real experience, but I'm not sure that's sensible at this size.

So maybe I go for a suspended wooden floor after all - any advice on how best to do it? Bearing in mind one side of the shed would be over the existing slabs, and the other over what's currently grass. Frame and joists of treated 4" timbers and sturdy floorboards over?

Anyway, any advice on the job is welcome. And apologies for any Google wierdnesses in this post - I used to post to uk.d-i-y regularly years ago, but I no longer have a news account or a reader installed.

Cheers,

Pete


What we do out here.
http://www.sheds.com.au/catalogue/ga...orkshops/index

Pete wrote:
Hello,

I currently have as a workshop a cheap Yardmaster metal shed. With some modifications (interior boarding, polystyrene in the roof, etc) it's served me adequately for the last five years or so, but I really want to expand. In particular, I've just inherited a lovely old metalworking lathe, and there's no way I can set it up in the present space. So, time for a new shed.

What I have in mind is a timber structure - CLS frame, OSB interior lining, bit of rockwool between the studs, and feather-edge or possibly shiplap boards on the outside. Not sure of the roof, I guess a ridge with the shallowest pitch I can reasonably get away with (don't want anything too dominatingly high) and decent felt, but I'm open to ideas.

Seems simple enough, but then I heard about building regs. Apparently if you're over 15m^2 (which I will be, there's no point otherwise) and within a metre of the boundary (which I also will be - the garden is long but narrow and I really need to use the full width) then you're not allowed to build in wood under the BR exemption.

I did do some very rough costings for a blockwork shed or a prefab concrete a couple of years ago - I can't remember the details but I know it came out pretty pricey (then again, I haven't done even rough costs for timber, but it surely must be less). Also I'm a crappy bricklayer but I can shoot screws into softwood all day and come out with something reasonable at the end. So I want to stick with the wooden structure if I can.

I've never done anything involving Building Regs before. If I talk to the guys at the council, are they likely to say "sure, go ahead", "Yes, but here are many onerous rules to follow", or a flat-out "no, you can't build it in wood because of the Great Fire of London"? This is in Southampton, if it matters. The proposed site is at the bottom of my garden, surrounded on all sides by the bottoms of other people's gardens in a typical Victorian semis layout.

Separately, assuming the wooden plan is a goer, I don't really know what to do about the floor. The current shed sits on a base of paving slabs laid by the previous owner, rather like a patio. I'm not sure exactly what's under them; the edges are raised about 6" with some cement visible so they're not just flat on the ground, but I don't know how much structure there is. This patio is too small for the new shed; I would need to either extend off one side of it or demolish it and start again. Such groundworks are complicated by the lack of access to the garden except through my hallway and living room.

I like the idea of a concrete floor, especially since I will be fitting the lathe and in due course probably a table saw and other large tools. I'm not quite sure how to start off a wooden building from that, but I'm sure there's a way. So smash up the existing plinth and use it as filler in a newly laid one? That's a lot of concrete though (5m x 7m x however thick). I'm imagining a great big hose being laid through the house from a lorry outside and pumping it in, but I've no idea if such a system even exists, let alone can be had at reasonable cost. The other option is to get a mixer (there's a guy at work hires out a Belle Minimix) and do it with barrows and shovels - I have no real experience, but I'm not sure that's sensible at this size.

So maybe I go for a suspended wooden floor after all - any advice on how best to do it? Bearing in mind one side of the shed would be over the existing slabs, and the other over what's currently grass. Frame and joists of treated 4" timbers and sturdy floorboards over?

Anyway, any advice on the job is welcome. And apologies for any Google wierdnesses in this post - I used to post to uk.d-i-y regularly years ago, but I no longer have a news account or a reader installed.

Cheers,

Pete



My shed.
https://picasaweb.google.com/1130203... t=directlink

/ F Murtz

-show quotedtext -My shed. https://picasaweb.google.com/1130203...470958/Camera? authuser=0&authkey= Gv1sRgCPnvk9rr35zeGg&feat=directlink/q

And you built that yourself?

Jim K

In message , Pete
writes
What I have in mind is a timber structure - CLS frame, OSB interior
lining, bit of rockwool between the studs, and feather-edge or possibly
shiplap boards on the outside. Not sure of the roof, I guess a ridge
with the shallowest pitch I can reasonably get away with (don't want
anything too dominatingly high) and decent felt, but I'm open to ideas.

I was lucky in that there was a rotten wooden structure here that had
been used as a stables, so I just went ahead and replaced it with a
similar sized wooden shed to house the lathe, milling machine, drill
etc.

We had a concrete plinth laid by a small local contractor who also did
the flagstone path to cover the power cable that I laid. The plinth had
a dpc sheet, then expanded polystyrene sheet, then plywood, then carpet
on top. I use rubber sheet on top of this where oil is likely to fly.

The shed has double doors at one end so that long thin things can be
poked in to be worked on. The machinery is in a line along one wall, but
this is sometimes frustrating because of the access. I think I would
consider setting up machinery away from the wall if I were starting
again.

The roof has a shallow pitch, but I really miss the storage space in the
steeply pitched roof of the shed in the previous house.

This shed has now done 15+ years. It has had 2 felt roofs, but now has
Onduline on top.

If you have a SWMBO at home, I can really recommend getting her to look
after local contractors rather than diy'ing. Innocence and steady tea
and biscuits go a long way.
--
Bill

JimK wrote:
/ F Murtz

-show quotedtext -My shed. https://picasaweb.google.com/1130203...470958/Camera? authuser=0&authkey= Gv1sRgCPnvk9rr35zeGg&feat=directlink/q

And you built that yourself?

Jim K

Could have done, they supply it as a kit,But I let them do it,Got the
slab poured and their team put the whole thing up in a day.It would have
taken me a lot longer.

09:23F Murtz
- show quoted text -
Could have done, they supply it as a kit,But I let them do it,Got the
slab poured and their team put the whole thing up in a day.It would have
taken me a lot longer/q

Mmm thought so ;^)

Jim K

In message , JimK
writes
/ F Murtz

-show quotedtext -My shed.
https://picasaweb.google.com/1130203...470958/Camera?
authuser=0&authkey= Gv1sRgCPnvk9rr35zeGg&feat=directlink/q

And you built that yourself?

Funny! That link works in Explorer but not in my version of Firefox!

--
Tim Lamb

JimK wrote:

09:23F Murtz
- show quoted text -
Could have done, they supply it as a kit,But I let them do it,Got the
slab poured and their team put the whole thing up in a day.It would have
taken me a lot longer/q

Mmm thought so ;^)

Jim K


They also supply whatever size you want as a kit.
Regardless of your put down comment (what is a ;^ )they are relatively
easy to put up, a few dynabolts into the slab and some bolts and nuts,
and loads of tec screws.
Lots of people erect their own, easier with smaller ones.
Mine is now full of machinery so I can build things like this (on my own)

http://tinypic.com/r/xc2f61/8

http://tinypic.com/r/2r54228/8

On Tue, 17 Jun 2014 10:15:42 +0100, Tim Lamb
wrote:

In message , JimK
writes
/ F Murtz

-show quotedtext -My shed.
https://picasaweb.google.com/1130203...470958/Camera?
authuser=0&authkey= Gv1sRgCPnvk9rr35zeGg&feat=directlink/q

And you built that yourself?

Funny! That link works in Explorer but not in my version of Firefox!

The page was devoid of photos when viewed with Opera 12.02 until I
refreshed the page. Might be worth trying FF again and a page refresh.
--
J B Good

In article om, F
Murtz scribeth thus
JimK wrote:

09:23F Murtz
- show quoted text -
Could have done, they supply it as a kit,But I let them do it,Got the
slab poured and their team put the whole thing up in a day.It would have
taken me a lot longer/q

Mmm thought so ;^)

Jim K


They also supply whatever size you want as a kit.
Regardless of your put down comment (what is a ;^ )they are relatively
easy to put up, a few dynabolts into the slab and some bolts and nuts,
and loads of tec screws.
Lots of people erect their own, easier with smaller ones.
Mine is now full of machinery so I can build things like this (on my own)

http://tinypic.com/r/xc2f61/8

Sweet..

But it does beg a question ..

... Just where is the rocking horse muck;?....


http://tinypic.com/r/2r54228/8

--
Tony Sayer

In article , Bill
scribeth thus
In message , Pete
writes
What I have in mind is a timber structure - CLS frame, OSB interior
lining, bit of rockwool between the studs, and feather-edge or possibly
shiplap boards on the outside. Not sure of the roof, I guess a ridge
with the shallowest pitch I can reasonably get away with (don't want
anything too dominatingly high) and decent felt, but I'm open to ideas.

I was lucky in that there was a rotten wooden structure here that had
been used as a stables, so I just went ahead and replaced it with a
similar sized wooden shed to house the lathe, milling machine, drill
etc.

We had a concrete plinth laid by a small local contractor who also did
the flagstone path to cover the power cable that I laid. The plinth had
a dpc sheet, then expanded polystyrene sheet, then plywood, then carpet
on top. I use rubber sheet on top of this where oil is likely to fly.

The shed has double doors at one end so that long thin things can be
poked in to be worked on. The machinery is in a line along one wall, but
this is sometimes frustrating because of the access. I think I would
consider setting up machinery away from the wall if I were starting
again.

The roof has a shallow pitch, but I really miss the storage space in the
steeply pitched roof of the shed in the previous house.

This shed has now done 15+ years. It has had 2 felt roofs, but now has
Onduline on top.



If you have a SWMBO at home, I can really recommend getting her to look
after local contractors rather than diy'ing. Innocence and steady tea
and biscuits go a long way.


So shes well experienced at satisfying the needs of a man then;?......

--
Tony Sayer

On Tuesday, June 17, 2014 3:18:44 PM UTC+1, tony sayer wrote:
If you have a SWMBO at home, I can really recommend getting her to look
after local contractors rather than diy'ing. Innocence and steady tea
and biscuits go a long way.
So shes well experienced at satisfying the needs of a man then;?......

Or several men simultaneously, depending on how big the erec, erm, building going up.

Most builders do prefer the larger cup size, given a choice.

Owain

On Monday, June 16, 2014 8:00:03 PM UTC+1, Pete wrote:

Seems simple enough, but then I heard about building regs. Apparently if you're over 15m^2 (which I will be, there's no point otherwise) and within a metre of the boundary (which I also will be - the garden is long but narrow and I really need to use the full width) then you're not allowed to build in wood under the BR exemption.


is that correct, and if it's less than 15 sqm can you build a wooden shed adjacent to the boundary without needing to satisfy any fire-regulations?

In fact I can't find a building reg for fire other than reg B on dwellinghouses, and a shed is not a dwelling house.



Robert

On Wednesday, June 18, 2014 1:32:45 PM UTC+1, RobertL wrote:
On Monday, June 16, 2014 8:00:03 PM UTC+1, Pete wrote:



Seems simple enough, but then I heard about building regs. Apparently if you're over 15m^2 (which I will be, there's no point otherwise) and within a metre of the boundary (which I also will be - the garden is long but narrow and I really need to use the full width) then you're not allowed to build in wood under the BR exemption.





is that correct, and if it's less than 15 sqm can you build a wooden shed adjacent to the boundary without needing to satisfy any fire-regulations?



In fact I can't find a building reg for fire other than reg B on dwellinghouses, and a shed is not a dwelling house.


Ah yes, I found this on planning portal:


"If you want to put up small detached buildings such as a garden shed or summerhouse in your garden, building regulations will not normally apply if the floor area of the building is less than 15 square metres and contains NO sleeping accommodation."


Robert

Hello again :-)

Sorry it's taken me a while to reply - when you're not reading a group regularly it's easy to forget to check in. Thanks for the useful replies - the heads up on fire-resistant fake cement planks hopefully means it's still a goer even if the BCO insists on not using wood cladding. I know I need to contact him (the Southampton council website seems to make that reasonably easy) but I haven't got round to it yet.

On access - the house on one side does have an alley and gate, but there's a brick wall between us. The house is a student let, and I've never met the landlord. It's not totally impossible, but neither is it as simple as asking a favour from a neighbour you see every day. On the other side are two other houses (mine is part of a unit of three, where one of the original big semis was pulled down) and then I'm not sure if there's a gap at that end either.

I have had a rough estimate for the concrete part of the job - a boom truck that can reach right over the house and to the end of the garden would be about four hundred quid for a short day and that is a price I am willing to pay to avoid barrowing several cubic metres of concrete through my living room. The main reason I'm coming back (as well as to say thanks) is to ask about making the base. Assuming I have concrete descending from the sky on request, what should I be putting under (or in) it?

I have the old slab patio which needs to be broken up and disposed of, so I guess I have a certain amount of hardcore in situ. I want to limit the amount of other sand/gravel/etc involved where possible, because that can't be magicked over the house. If that can be traded off against more concrete (within reason) then I probably want to do that.

I know I need to set up formwork around the slab site, and have a long batten reaching right across to level the surface. I don't know much else about laying concrete. Would a slab this size (4.5m x 7m) need any kind of reinforcement within it?

I had been assuming that the base would be wider than the shed, but I've since read something that advises against it - for the same excellent reason that you don't want your groundsheet sticking out from under your tent. If the body of the shed effectively shelters the slab, then it will help prevent damp inside. This is a very important consideration, as I will be storing a lot of stuff inside, from fabrics to electronics, and also plenty of tools which I don't want to rust. I guess I should also be using some DPM somewhere in the mix?

I'd prefer to have a plain concrete floor rather than lay wood on top of it, but how smooth am I likely to be able to get it when laying the slab? Or is it inevitably going to require some kind of screed on top? Doesn't need to be skating-rink smooth, but I'm thinking of having a couple of movable tool-chests on say 4" wheels and I want to be able to push them around.

I plan to embed a couple of L-shaped conduits for wiring (one for 240v, one for anything else I might want later). I would place these with a slight downward slope towards the underground end, so that they don't fill up with water. I don't have in mind any plumbing beyond perhaps a waterbutt and a small soakaway under its tap.

Any other advice on preparing and laying the slab is welcome.

Thanks,

Pete

On 29/06/14 17:42, wrote:
Hello again :-)

Sorry it's taken me a while to reply - when you're not reading a
group regularly it's easy to forget to check in. Thanks for the
useful replies - the heads up on fire-resistant fake cement planks
hopefully means it's still a goer even if the BCO insists on not
using wood cladding. I know I need to contact him (the Southampton
council website seems to make that reasonably easy) but I haven't got
round to it yet.

On access - the house on one side does have an alley and gate, but
there's a brick wall between us. The house is a student let, and I've
never met the landlord. It's not totally impossible, but neither is
it as simple as asking a favour from a neighbour you see every day.
On the other side are two other houses (mine is part of a unit of
three, where one of the original big semis was pulled down) and then
I'm not sure if there's a gap at that end either.

I have had a rough estimate for the concrete part of the job - a boom
truck that can reach right over the house and to the end of the
garden would be about four hundred quid for a short day and that is a
price I am willing to pay to avoid barrowing several cubic metres of
concrete through my living room. The main reason I'm coming back (as
well as to say thanks) is to ask about making the base. Assuming I
have concrete descending from the sky on request, what should I be
putting under (or in) it?

I have the old slab patio which needs to be broken up and disposed
of, so I guess I have a certain amount of hardcore in situ. I want to
limit the amount of other sand/gravel/etc involved where possible,
because that can't be magicked over the house. If that can be traded
off against more concrete (within reason) then I probably want to do
that.

You could smash the concrete up and run a vibrating plate compactor over
it to get you a well walloped base for the concrete.

I know I need to set up formwork around the slab site, and have a
long batten reaching right across to level the surface. I don't know
much else about laying concrete. Would a slab this size (4.5m x 7m)
need any kind of reinforcement within it?

I would. Mesh is not expensive nor heavy for 2 people to carry through
the house (8x4' sections).

I had been assuming that the base would be wider than the shed, but
I've since read something that advises against it - for the same
excellent reason that you don't want your groundsheet sticking out
from under your tent. If the body of the shed effectively shelters
the slab, then it will help prevent damp inside. This is a very
important consideration, as I will be storing a lot of stuff inside,
from fabrics to electronics, and also plenty of tools which I don't
want to rust. I guess I should also be using some DPM somewhere in
the mix?

Yes - if you can, sizing it for the shed so you can curtain the shed
walls over the edge will keep water from pooling under the shed and will
make the floor bearers last forever.

If you wanted DPC you would need to blind your hardcore with sand,
vibro-tamp that down then lay sheet then pour concrete.


I'd prefer to have a plain concrete floor rather than lay wood on top
of it, but how smooth am I likely to be able to get it when laying
the slab? Or is it inevitably going to require some kind of screed on
top? Doesn't need to be skating-rink smooth, but I'm thinking of
having a couple of movable tool-chests on say 4" wheels and I want to
be able to push them around.

A simpler solution would be to paint the shed floor with epoxy paint
which will form a DPM on top of the concrete and give you a good
surface. You will need to let the concrete cure, dry (several weeks),
wire brush it to get the laitance off (cement/salt bloom).

A cheap solution would be to lay some cheap vinyl on top and accept it
may need replacing from time to time (I expect it will last quite a long
time).


I plan to embed a couple of L-shaped conduits for wiring (one for
240v, one for anything else I might want later). I would place these
with a slight downward slope towards the underground end, so that
they don't fill up with water. I don't have in mind any plumbing
beyond perhaps a waterbutt and a small soakaway under its tap.

If you can get some, some larger bore blue MDPE pipe would give you a
continuous (jointless) tube with a nice smooth wall to pull SWA or other
cables through. Lay several. You're right about the downward slop to
outside - good move


Any other advice on preparing and laying the slab is welcome.

Thanks,

Pete

On Sunday, June 29, 2014 6:40:18 PM UTC+1, Tim Watts wrote:
On 29/06/14 17:42, Pete wrote:

I have the old slab patio which needs to be broken up and disposed
of, so I guess I have a certain amount of hardcore in situ. I want to
limit the amount of other sand/gravel/etc involved where possible,
because that can't be magicked over the house.

You could smash the concrete up and run a vibrating plate compactor over
it to get you a well walloped base for the concrete.

That's the kind of thing I had in mind, yes. Although the planned slab is just over twice the size of the existing base, so it will be spread relatively thinly. How thick a layer would be recommended if I was starting from scratch? Also, how thick the actual concrete slab itself? The company I got the estimate from said they'd assumed 100mm - that about right?

Would a slab this size (4.5m x 7m) need any kind of reinforcement within it?

I would. Mesh is not expensive nor heavy for 2 people to carry through
the house (8x4' sections).

OK. The stuff I've found with a quick google is quite pricey, but I think it's massive sizes meant for serious civil engineering. Will have to come up with some better search terms.

Yes - if you can, sizing it for the shed so you can curtain the shed
walls over the edge will keep water from pooling under the shed and will
make the floor bearers last forever.

That's what I had in mind, together with gravel in the half-metre gap between the base and the foot of the surrounding wall and fences. I wasn't planning a raised floor though...

If you wanted DPC you would need to blind your hardcore with sand,
vibro-tamp that down then lay sheet then pour concrete.

I'd prefer to have a plain concrete floor rather than lay wood on top
of it, but how smooth am I likely to be able to get it

A simpler solution would be to paint the shed floor with epoxy paint
which will form a DPM on top of the concrete and give you a good
surface.

To be clear, if I did this I wouldn't need the DPM under the slab, and so wouldn't need the sand blinding layer? And it would provide just as good protection against damp? If so, it sounds like two birds with one stone, and well worth doing. Remember, I attach a high cost to any additional aggregates because they have to come through my living room!

You will need to let the concrete cure, dry (several weeks),
wire brush it to get the laitance off (cement/salt bloom).

I can probably manage the curing time, as I plan to bodily shift the existing shed onto the main house patio to store the contents while the slab is prepared. Remove the contents, and the internal boarding, and bolt some handles on the outside. Then undo the anchor bolts and, with a few mates, walk it up the garden!

How would I go about wire-brushing the surface? I assume you don't mean spending hours with the kind of hand brush I clean rusty metal with :-)

A cheap solution would be to lay some cheap vinyl on top and accept it
may need replacing from time to time (I expect it will last quite a long
time).

That's more or less what I did with the existing shed (actually it was DPM laid directly onto the paving and OSB on top of it - real bodge job). But I want to make a proper job of this one, and since I'm planning to install a lot of built-in furniture (benches, racking, even a small internal room for dust-free varnishing) I don't want to ever have to take the floor up.

I'd also worry that anything not actually bonded to the concrete would fail to keep the damp out.

If you can get some, some larger bore blue MDPE pipe would give you a
continuous (jointless) tube with a nice smooth wall to pull SWA or other
cables through.

I was thinking of 40mm solvent-weld waste pipe, with a swept bend at the corner. Originally it was going to be a single conduit of 100mm, as I have some lurking in the shed from a bathroom refit, but I realised that sharing the conduit between 240v and, say, ethernet, was not best practice even though with SWA the risk seems minimal.

Cheers,

Pete

On 29/06/14 19:50, wrote:

That's the kind of thing I had in mind, yes. Although the planned
slab is just over twice the size of the existing base, so it will be
spread relatively thinly. How thick a layer would be recommended if I
was starting from scratch? Also, how thick the actual concrete slab
itself? The company I got the estimate from said they'd assumed 100mm
- that about right?

100mm is about right on a well tamped base.


Would a slab this size (4.5m x 7m) need any kind of reinforcement
within it?

I would. Mesh is not expensive nor heavy for 2 people to carry
through the house (8x4' sections).

OK. The stuff I've found with a quick google is quite pricey, but I
think it's massive sizes meant for serious civil engineering. Will
have to come up with some better search terms.

Typically about £20/sheet

http://www.metals4u.co.uk/mild-steel...p?prd_id=10830

Yes - if you can, sizing it for the shed so you can curtain the
shed walls over the edge will keep water from pooling under the
shed and will make the floor bearers last forever.

That's what I had in mind, together with gravel in the half-metre gap
between the base and the foot of the surrounding wall and fences. I
wasn't planning a raised floor though...

OK


If you wanted DPC you would need to blind your hardcore with sand,
vibro-tamp that down then lay sheet then pour concrete.

I'd prefer to have a plain concrete floor rather than lay wood on
top of it, but how smooth am I likely to be able to get it

A simpler solution would be to paint the shed floor with epoxy
paint which will form a DPM on top of the concrete and give you a
good surface.

To be clear, if I did this I wouldn't need the DPM under the slab,
and so wouldn't need the sand blinding layer? And it would provide
just as good protection against damp?

Yes - you are just moving the DPM to the top surface.

If so, it sounds like two birds
with one stone, and well worth doing. Remember, I attach a high cost
to any additional aggregates because they have to come through my
living room!

You will need to let the concrete cure, dry (several weeks), wire
brush it to get the laitance off (cement/salt bloom).

I can probably manage the curing time, as I plan to bodily shift the
existing shed onto the main house patio to store the contents while
the slab is prepared. Remove the contents, and the internal boarding,
and bolt some handles on the outside. Then undo the anchor bolts and,
with a few mates, walk it up the garden!

How would I go about wire-brushing the surface? I assume you don't
mean spending hours with the kind of hand brush I clean rusty metal
with :-)


Yes - it only takes a light brushing (usually) to remove laitance - and
you may not even get any. If the surface is solid and not powdery, paint
straight on. Too wet concrete can get laitance and too dry can have
sandy surface. If the mix is right, and you don't overdo the final
floating it should have a good surface - especially as you will be
dropping it into hardcore so excess water will not pool.

A cheap solution would be to lay some cheap vinyl on top and accept
it may need replacing from time to time (I expect it will last
quite a long time).

That's more or less what I did with the existing shed (actually it
was DPM laid directly onto the paving and OSB on top of it - real
bodge job). But I want to make a proper job of this one, and since
I'm planning to install a lot of built-in furniture (benches,
racking, even a small internal room for dust-free varnishing) I don't
want to ever have to take the floor up.

I'd also worry that anything not actually bonded to the concrete
would fail to keep the damp out.

You could look at:

http://www.f-ball.co.uk/product_category.asp?catID=damp

I used F75. All of those assume you will put something else on top,
however it's pretty tough stuff and I would think it would stand up to
foot traffic pretty well.

But it might be worth looking at some epoxy floor paints (rather than
DPMs) - you may find something more suited.


If you can get some, some larger bore blue MDPE pipe would give you
a continuous (jointless) tube with a nice smooth wall to pull SWA
or other cables through.

I was thinking of 40mm solvent-weld waste pipe, with a swept bend at
the corner.

Make sure the bend is very swept - the bends I'm familiar with will be a
little tight. Don't overlook the fact the joints will act as a snag
point right where you don't need snags. I had this with even a straight
coupling in ordinary conduit.

Originally it was going to be a single conduit of 100mm,
as I have some lurking in the shed from a bathroom refit, but I
realised that sharing the conduit between 240v and, say, ethernet,
was not best practice even though with SWA the risk seems minimal.