Hi all,

I am planning to convert a single-skinned, block-built outbuilding into
a workshop. I have read many other posts about this type of project,
and know roughly what I need to do, but I have a few specific
questions:

1) The building has a rough concrete floor, which I plan to raise
slightly (about 5cm), and level off. I need about 0.5 m^3 of concrete.
How do I convert this volume into the required bags of concrete, sand
and ballast? Are there tables anywhere that I can use?

2) I notice that cement is sold in 25kg bags, but sand and ballast are
typically sold in `bags', or `jumbo bags' (big canvas things), with no
indication of their weight/volume. If I am ordering material to mix
concrete in a specific ratio (e.g., 1:3:6) do I use `bags', or do I
have to convert a sand `bag' into the appropriate weight to match the
cement weighy, and order by that quantity instead? Is a `jumbo bag' a
specific number of `bags'?

3) I am going to dry-line the walls. I have seen two different
approaches to putting in the membrane: some people state that it should
be placed next to the wall, underneath the battens, and others state
that it should go between the battens and the facing material. Which is
correct, or should different methods be used for different purposes?

4) Facing material seems to be sold in widths of 600mm, or 1200mm. If I
use 3x2 battens, fastened at 600mm centres, then the gap between the
battens is about 520mm. I'm curious as to why insulation material isn't
sold in these widths, at least for common batten sizes?

5) Insulation: should I use mineral wool, or polystyrene? I haven't
been able to find any meaningful comparisons, so what factors determine
which is the better option?

thanks,

dan.

wrote:
Hi all,

I am planning to convert a single-skinned, block-built outbuilding into
a workshop. I have read many other posts about this type of project,
and know roughly what I need to do, but I have a few specific
questions:

1) The building has a rough concrete floor, which I plan to raise
slightly (about 5cm), and level off. I need about 0.5 m^3 of concrete.
How do I convert this volume into the required bags of concrete, sand
and ballast? Are there tables anywhere that I can use?

Itds about 3 tons per cube meter so thats very close to a ton of
ballast.. Mm. probably half in half sand and gravel..and I used to find
that a tin bag of sand took about 6 bags of cement to make into a fairly
weak mortar..so 6 bags of cement should do it. They aren't so bad - you
can always nip down the BM and get another one, but tonne bags of
ballast come delivered on 30 ton trucks..

Are you putting a DPM under the new concrete? Or insulation?

Is there a DPC in the blockwork already?


2) I notice that cement is sold in 25kg bags, but sand and ballast are
typically sold in `bags', or `jumbo bags' (big canvas things), with no
indication of their weight/volume. If I am ordering material to mix
concrete in a specific ratio (e.g., 1:3:6) do I use `bags', or do I
have to convert a sand `bag' into the appropriate weight to match the
cement weighy, and order by that quantity instead? Is a `jumbo bag' a
specific number of `bags'?

Big bags are 850kg - roughly a ton wet. Frankly if you are concreting
that amount, get a 'ton bag' of sand and gravel both..

3) I am going to dry-line the walls. I have seen two different
approaches to putting in the membrane: some people state that it should
be placed next to the wall, underneath the battens, and others state
that it should go between the battens and the facing material. Which is
correct, or should different methods be used for different purposes?

If you are insulating it ought to go on the inside of the studwork -
simple is foil backed plasterboard. A breathable membrane on the outside
of the studs is useful if there is any chance of holes in the outer
structure with e.g. weatherboarding.


4) Facing material seems to be sold in widths of 600mm, or 1200mm. If I
use 3x2 battens, fastened at 600mm centres, then the gap between the
battens is about 520mm. I'm curious as to why insulation material isn't
sold in these widths, at least for common batten sizes?


Normal studwork spacing is 400mm. Insulation never fits anyway due to
different people using different stud widths. Accept it.


5) Insulation: should I use mineral wool, or polystyrene? I haven't
been able to find any meaningful comparisons, so what factors determine
which is the better option?

Never use poly in a wall. Its for under concrete use only IMHO.

Rock wool is cheap, but celotex (polyisocyanurate foam board) is better.
However running cables/pipes with it is more painful.

thanks,

dan.

The message . com
from " contains these words:

1) The building has a rough concrete floor, which I plan to raise
slightly (about 5cm), and level off. I need about 0.5 m^3 of concrete.
How do I convert this volume into the required bags of concrete, sand
and ballast? Are there tables anywhere that I can use?

2) I notice that cement is sold in 25kg bags, but sand and ballast are
typically sold in `bags', or `jumbo bags' (big canvas things), with no
indication of their weight/volume. If I am ordering material to mix
concrete in a specific ratio (e.g., 1:3:6) do I use `bags', or do I
have to convert a sand `bag' into the appropriate weight to match the
cement weighy, and order by that quantity instead? Is a `jumbo bag' a
specific number of `bags'?

Concrete ratios are typically specified in terms of volume. 1:3:6 seems
a bit thin to me but no doubt you have already taken advice on that.

Buying sand (and you want sharp sand for concrete) and gravel in tiny
bags is a very expensive way of doing it. Loose is usually the cheapest
but you need a good area to dump it on as it takes more room than a 1
tonne bag and if the surface isn't clean and solid you will have some
waste.

FWIW 1 cubic yard of 1:2:4 concrete takes 0.231 tons of cement, 0.513
tons of sand and 0.933 tons of gravel. As this is a diy ng I will leave
it to you to convert those figures from Imperial to metric. :-)

--
Roger Chapman

"The Natural Philosopher" wrote in message
...
snip can always nip down the BM and get another one, but tonne
bags of
ballast come delivered on 30 ton trucks..

Err no they don't, unless you meant 20, anything from a 5 ton truck
up, although 12 ton is more common.

A 30 ton truck would be a tractor and (medium weight) trailer unit,
how many BM's use them for site delivery, although direct deliveries
of brick and block work often do.

Jerry wrote:
"The Natural Philosopher" wrote in message
...
snip can always nip down the BM and get another one, but tonne
bags of
ballast come delivered on 30 ton trucks..

Err no they don't, unless you meant 20, anything from a 5 ton truck
up, although 12 ton is more common.

A 30 ton truck would be a tractor and (medium weight) trailer unit,
how many BM's use them for site delivery, although direct deliveries
of brick and block work often do.


Mine do :-) Massive great things..I agree they only use the artics for
the biggest stuff though..but my 20 tons of gravel didn't come in
either a 20 tonne trick OR an artic either. ISTR the tipper had 6 or 8
sets of wheels of which at least two sets were steerable and at least
one set were double..

I wish he had come back after I had raked it all out and helped smack it
down..

wrote:

1) The building has a rough concrete floor, which I plan to raise
slightly (about 5cm), and level off. I need about 0.5 m^3 of concrete.
How do I convert this volume into the required bags of concrete, sand
and ballast? Are there tables anywhere that I can use?

http://www.pavingexpert.com/calcall.htm#focus01

Look for the concrete calculators.

2) I notice that cement is sold in 25kg bags, but sand and ballast are
typically sold in `bags', or `jumbo bags' (big canvas things), with no
indication of their weight/volume. If I am ordering material to mix

The jumbo bags are notionally 1 tonne - but it does depend on the water
content. They may contain as little as 800kg, especially if the stuff is
very dry.

concrete in a specific ratio (e.g., 1:3:6) do I use `bags', or do I
have to convert a sand `bag' into the appropriate weight to match the
cement weighy, and order by that quantity instead? Is a `jumbo bag' a
specific number of `bags'?

Mix by volume.... buckets / spades full etc.

3) I am going to dry-line the walls. I have seen two different
approaches to putting in the membrane: some people state that it should
be placed next to the wall, underneath the battens, and others state
that it should go between the battens and the facing material. Which is
correct, or should different methods be used for different purposes?

Against the wall will save you needing to pierce it ever flush socket
box etc.

4) Facing material seems to be sold in widths of 600mm, or 1200mm. If I
use 3x2 battens, fastened at 600mm centres, then the gap between the
battens is about 520mm. I'm curious as to why insulation material isn't
sold in these widths, at least for common batten sizes?

If you speak to a insulation board supplier you will find that there are
many standard sizes available - some designed with exactly this in mind.
Note however that unless you insert the insulation as you go you will
innevitibly need to do some cutting to make it fit.

5) Insulation: should I use mineral wool, or polystyrene? I haven't
been able to find any meaningful comparisons, so what factors determine
which is the better option?

Best material is a ridgid PIR foam like celotex or kingspan. PIR foam
will give you more insulation for a given thickness than just about any
other type. Next would be ridgid polystyrene, semi ridgid rockwoll
batts, then at the least desireable end things like fibreglass wool /
rockwool.

See http://www.secondsandco.co.uk/


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In message , John
Rumm writes
wrote:

5) Insulation: should I use mineral wool, or polystyrene? I haven't
been able to find any meaningful comparisons, so what factors determine
which is the better option?

Best material is a ridgid PIR foam like celotex or kingspan. PIR foam
will give you more insulation for a given thickness than just about any
other type. Next would be ridgid polystyrene, semi ridgid rockwoll
batts, then at the least desireable end things like fibreglass wool /
rockwool.

I would avoid expanded polystyrene in this context as any electrical
cable run through it etc. would need protecting from it.
--
Chris French

"John Rumm" wrote in message
...
wrote:

snip

3) I am going to dry-line the walls. I have seen two different
approaches to putting in the membrane: some people state that it
should
be placed next to the wall, underneath the battens, and others
state
that it should go between the battens and the facing material.
Which is
correct, or should different methods be used for different
purposes?

Against the wall will save you needing to pierce it ever flush
socket
box etc.

It will also save the stud work from damp.

"chris French" wrote in message
...
In message ,
John
Rumm writes
wrote:

5) Insulation: should I use mineral wool, or polystyrene? I
haven't
been able to find any meaningful comparisons, so what factors
determine
which is the better option?

Best material is a ridgid PIR foam like celotex or kingspan. PIR
foam
will give you more insulation for a given thickness than just
about any
other type. Next would be ridgid polystyrene, semi ridgid rockwoll
batts, then at the least desireable end things like fibreglass
wool /
rockwool.

I would avoid expanded polystyrene in this context as any
electrical
cable run through it etc. would need protecting from it.

Personally, as this is going to be a workshop, I would opt for
surface conduit and or Trunking - makes later alterations far more
simple when you need that extra socket or machine supply.

Jerry wrote:
"chris French" wrote in message
...
In message ,
John
Rumm writes
wrote:

5) Insulation: should I use mineral wool, or polystyrene? I
haven't
been able to find any meaningful comparisons, so what factors
determine
which is the better option?
Best material is a ridgid PIR foam like celotex or kingspan. PIR
foam
will give you more insulation for a given thickness than just
about any
other type. Next would be ridgid polystyrene, semi ridgid rockwoll
batts, then at the least desireable end things like fibreglass
wool /
rockwool.

I would avoid expanded polystyrene in this context as any
electrical
cable run through it etc. would need protecting from it.

Personally, as this is going to be a workshop, I would opt for
surface conduit and or Trunking - makes later alterations far more
simple when you need that extra socket or machine supply.


I would say no. If foil backed plasterboard is used, hacking out a
section, laying cables using coathangers etc and replacing, making good
and painting is VERY quick.

And leaves the walls free to hang cupboards etc.

"The Natural Philosopher" wrote in message
...
Jerry wrote:
snip

Personally, as this is going to be a workshop, I would opt for
surface conduit and or Trunking - makes later alterations far
more
simple when you need that extra socket or machine supply.


I would say no. If foil backed plasterboard is used, hacking out a
section, laying cables using coathangers etc and replacing, making
good
and painting is VERY quick.

And leaves the walls free to hang cupboards etc.

I would say that drilling a hole in trunking either mounting a socket
or dropping a length of conduit is even quicker - installing a new
cable or altering an existing cable is certainly quicker. As for
leaving the walls clear, that all depends of how you design the
installation, trunking / conduit can be mounted above bench level but
below cupboard height.

On 25 Aug 2006 08:50:28 -0700, "
wrote:


1) The building has a rough concrete floor, which I plan to raise
slightly (about 5cm), and level off.

Depending on what the workshop will be used for you might want to
consider plywood flooring on top of PIR foam - much kinder on the
feet :-).
--
Peter Parry.
http://www.wpp.ltd.uk/

Hi all,

Thanks for all your responses.

There is no DPC that I am aware of. I am going to put a membrane down
under the concrete, and extend it up the walls. If I use a single
sheet, then I am going to get lots of excess in the corners. If I cut
the excess away, then what should I use to waterproof the resulting
joints? IS having an overlap sufficient, or must the joints be sealed?

I agree that plywood flooring on foam is better under foot, but I want
a solid base to which to bolt my metal-working lathe.

thanks once again,

dan.

wrote:
Hi all,

Thanks for all your responses.

There is no DPC that I am aware of. I am going to put a membrane down
under the concrete, and extend it up the walls. If I use a single
sheet, then I am going to get lots of excess in the corners. If I cut
the excess away, then what should I use to waterproof the resulting
joints? IS having an overlap sufficient, or must the joints be sealed?


No. What A DPC does is to make it harder, not impossible, for water to
get past. The natural evaporation can take care of any that seeps through.

I am concerned though that the exterior walls are not DPC'ed.

I'd be inclined to line the bottom few feet of the whole thing with DPM
before studding out. And use a big overlap running under the concrete.

That way any 'rising damp' in the walls will have to rise a fair way -
with the chance of evaporating away first - before it gets to any wood work



I agree that plywood flooring on foam is better under foot, but I want
a solid base to which to bolt my metal-working lathe.


Proper workshop I see. nods approval, tinged with envy

thanks once again,

dan.

In article .com,
" writes:
Hi all,

Thanks for all your responses.

There is no DPC that I am aware of. I am going to put a membrane down
under the concrete, and extend it up the walls. If I use a single
sheet, then I am going to get lots of excess in the corners. If I cut
the excess away, then what should I use to waterproof the resulting
joints? IS having an overlap sufficient, or must the joints be sealed?

You don't cut the excess away. You fold the corners so it's
still sealed. The weight of the concrete pour also helps push
it back to whatever is retaining the concrete, but I suggest
creasing it deliberately to fold in the right places. Cut the
excess off neatly after the concrete has set, if you want to.

BTW, only 5cm thickness on a plastic membrane which isn't going
to stick to it sounds a bit dicey to me. I would probably look
for one of the paint-on moisture barriers in that case.

--
Andrew Gabriel

wrote:
Hi all,

I am planning to convert a single-skinned, block-built outbuilding
into a workshop. I have read many other posts about this type of
project, and know roughly what I need to do, but I have a few specific
questions:

1) The building has a rough concrete floor, which I plan to raise
slightly (about 5cm), and level off. I need about 0.5 m^3 of concrete.
How do I convert this volume into the required bags of concrete, sand
and ballast? Are there tables anywhere that I can use?


What area is it covering? - if you've worked it out at half a cube that
makes the total floor area only 10m2 @ 50mm thick...


2) I notice that cement is sold in 25kg bags, but sand and ballast are
typically sold in `bags', or `jumbo bags' (big canvas things), with no
indication of their weight/volume. If I am ordering material to mix
concrete in a specific ratio (e.g., 1:3:6) do I use `bags', or do I
have to convert a sand `bag' into the appropriate weight to match the
cement weighy, and order by that quantity instead? Is a `jumbo bag' a
specific number of `bags'?


There's too may 'bags' in this paragraph to make sense - if you intend using
a 1:3:6 ratio, then the 1 is the cement (25kg) the sand will be 75kg and the
stone 150kg
If you do only require half a metre and you intend putting it down only 50mm
thick it will need more cement than this, also you'd be wise to use 10mm
chippings, anything larger and you won't get a finish on it.
If you have a cement mixer, you'd be better off putting in 3 X 25kg bags of
stone, 2 bags of sand and a bag of cement.
You'll probably need at least 6 mixes of this size to do half a metre3,
meaning that you'll need 18 stone, 12 sand and six cement.