I'm planning on replacing our shed. The current one (over 60 years old!)
has the main vertical timbers set in a 4" concrete floor slab. The floor,
though quite solid, is uneven and on an incline of about 80mm over the long
length of the shed (9'x6' pent).

I'm trying to figure a way of creating a durable and level base from this
for a new shed (a standard pent 10'x6' with an integral floor). I'd like to
avoid ripping up the old concrete and/or pouring too much new concrete.

Without pouring a new slab, most of the ideas I have come up with involve
building various layouts of dwarf wall either with or without an additional
2"x6" timber frame on top (in attempt to cut down on the number of walls
needed).

The problem is that with the fall on the existing concrete, I would need to
cut alot of blocks. I'm considering the various 440mm concrete blocks and
wonder which are best in terms of suitability and ease of cutting. Also
will it be hard to get a finished level surface building like this?
Bearing in mind my setting out skills aren't bad but I've not done any brick
or block laying. It wouldn't be more than 1 course.

I'd be very grateful for any advice.

Dean wrote:


I'm planning on replacing our shed...

I acquired a shed recently which was sited on gravel. The suppliers laid
timber posts on the gravel first, then the reinforced floor of the shed went
across that so that the shed floor rests on the posts at regular intervals.
Although that might not provide as much ground contact as there would be if
the shed floor had been laid directly on, say, slabs, it also means that
there's much better air circulation under the shed.

Even heavy rain drains away through the gravel pretty quickly, so - I hope -
the base timeber will rarely be all that wet.

In your situation I'd consider a retaining wall around your base, and
filling the void with gravel.


--
Jeremy C B Nicoll - my opinions are my own.

Dean explained on 07/09/2008 :

I'm trying to figure a way of creating a durable and level base from this
for a new shed (a standard pent 10'x6' with an integral floor). I'd like to
avoid ripping up the old concrete and/or pouring too much new concrete.

I'm not clear on whether or not you are indicating that the new shed
will over hang the existing concrete base or not.

Generally get the wood lifted clear of the base with anything which
will prevent moisture tracking up through it - bricks, roofing tiles
and etc.. Put plenty of these in place, both around the perimeter and
at regular intervals under the floor joists. Air circulation and
keeping the timber dry is the key to preventing rot.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Harry Bloomfield wrote:
Dean explained on 07/09/2008 :

I'm trying to figure a way of creating a durable and level base from
this for a new shed (a standard pent 10'x6' with an integral floor).
I'd like to avoid ripping up the old concrete and/or pouring too
much new concrete.

I'm not clear on whether or not you are indicating that the new shed
will over hang the existing concrete base or not.

Generally get the wood lifted clear of the base with anything which
will prevent moisture tracking up through it - bricks, roofing tiles
and etc.. Put plenty of these in place, both around the perimeter and
at regular intervals under the floor joists. Air circulation and
keeping the timber dry is the key to preventing rot.

Concrete fence posts are good & very easy to lay.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

On Sun, 07 Sep 2008 11:25:19 +0100, Harry Bloomfield wrote:

Dean explained on 07/09/2008 :

I'm trying to figure a way of creating a durable and level base from this
for a new shed (a standard pent 10'x6' with an integral floor). I'd like to
avoid ripping up the old concrete and/or pouring too much new concrete.

I'm not clear on whether or not you are indicating that the new shed
will over hang the existing concrete base or not.

The extra foot of the new shed will be up hill from the existing base and
overhang existing patio slabs (these stand a bit proud of the concrete. I
planned on supporting the underside of the floor of the new shed to a level
50mm above this patio, this then determining the height of the required
dwarf walls across the sloping slab giving a max wall height of about 200mm.

Generally get the wood lifted clear of the base with anything which
will prevent moisture tracking up through it - bricks, roofing tiles
and etc.. Put plenty of these in place, both around the perimeter and
at regular intervals under the floor joists. Air circulation and
keeping the timber dry is the key to preventing rot.

This is a benefit that occurred to me when I thought of dwarf walls.
I thought of using large concrete blocks or regular bricks. Then hiring a
block splitter or angle grinder for a day. I'm wondering what type of
bricks will be easiest to cut or split. I think I'll struggle to reliably
split big 440mm blocks and I prefer to use a splitter rather than disc
cutter.

The under the floor of the sheds I looked at (and can afford) seems to be 2"
running long ways under thin t&g floor. Six dwarf walls would give support
about every 18". I wonder is that enough? The shed isn't going to contain
anything very heavy but will get fairly packed with stuff over time.

On Sun, 07 Sep 2008 12:35:40 +0100, Dean wrote:


I thought of using large concrete blocks or regular bricks. Then hiring a
block splitter or angle grinder for a day. I'm wondering what type of
bricks will be easiest to cut or split. I think I'll struggle to reliably
split big 440mm blocks and I prefer to use a splitter rather than disc
cutter.

I have just cut (in half) a few dense concrete 440mm blocks. Marked all way
round with a pencil then used 4.5" angle grinder with diamond blade to cut all
round (depth about 1"). A bolster chisel and lump hammer separated the two
halves. Takes 3-4 minutes per block max.
One block from Wickes cracked /before/ I used the hammer - but nowhere near the
cut. A second block is partially cracked. I then bought blocks from B&Q and
these have been no problem to cut.

Geo

Dean presented the following explanation :
The under the floor of the sheds I looked at (and can afford) seems to be 2"
running long ways under thin t&g floor. Six dwarf walls would give support
about every 18". I wonder is that enough? The shed isn't going to contain
anything very heavy but will get fairly packed with stuff over time.

Every 18" is quite adequate. The 2" sounds a bit on the thin side for a
large hut though. The front over hang of 12" doesn't sound as if it
will be a problem, even if it were to be left unsupported.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Sun, 07 Sep 2008 14:41:54 +0100, Harry Bloomfield wrote:

Dean presented the following explanation :
The under the floor of the sheds I looked at (and can afford) seems to be 2"
running long ways under thin t&g floor. Six dwarf walls would give support
about every 18". I wonder is that enough? The shed isn't going to contain
anything very heavy but will get fairly packed with stuff over time.

Every 18" is quite adequate.
The 2" sounds a bit on the thin side for a large hut though.

I have a particular shed in mind locally so I'll ask if I can have a
stronger floor.

The front over hang of 12" doesn't sound as if it
will be a problem, even if it were to be left unsupported.


Thanks to all for the advice.

On Sun, 07 Sep 2008 13:22:34 GMT, Geo wrote:

On Sun, 07 Sep 2008 12:35:40 +0100, Dean wrote:


I thought of using large concrete blocks or regular bricks. Then hiring a
block splitter or angle grinder for a day. I'm wondering what type of
bricks will be easiest to cut or split. I think I'll struggle to reliably
split big 440mm blocks and I prefer to use a splitter rather than disc
cutter.

I have just cut (in half) a few dense concrete 440mm blocks. Marked all way
round with a pencil then used 4.5" angle grinder with diamond blade to cut all
round (depth about 1"). A bolster chisel and lump hammer separated the two
halves. Takes 3-4 minutes per block max.
One block from Wickes cracked /before/ I used the hammer - but nowhere near the
cut. A second block is partially cracked. I then bought blocks from B&Q and
these have been no problem to cut.

Geo

Thanks. That's reassuring. I'll give it a go.

In message , Dean
writes

I'm planning on replacing our shed. The current one (over 60 years old!)
has the main vertical timbers set in a 4" concrete floor slab. The floor,
though quite solid, is uneven and on an incline of about 80mm over the long
length of the shed (9'x6' pent).

I'm trying to figure a way of creating a durable and level base from this
for a new shed (a standard pent 10'x6' with an integral floor). I'd like to
avoid ripping up the old concrete and/or pouring too much new concrete.


The problem is that with the fall on the existing concrete, I would need to
cut alot of blocks. I'm considering the various 440mm concrete blocks and
wonder which are best in terms of suitability and ease of cutting. Also
will it be hard to get a finished level surface building like this?
Bearing in mind my setting out skills aren't bad but I've not done any brick
or block laying. It wouldn't be more than 1 course.


When I put our old shed, on sloping ground I used half concrete blocks
bedded on the ground and then put treated timbers (fence posts as it
happens) across these and then the shed was rested on those.

It was a 10 x 6 shed, IIRC I put timbers across every 2 feet supported
at the ends and in the middle with concrete blocks.

You could probably do something similar if you don't want to lay lots of
blocks.
--
Chris French

On Sep 7, 9:18*am, Dean wrote:
I'm planning on replacing our shed. *The current one (over 60 years old!)
has the main vertical timbers set in a 4" concrete floor slab. *The floor,
though quite solid, is uneven and on an incline of about 80mm over the long
length of the shed (9'x6' pent).

I'm trying to figure a way of creating a durable and level base from this
for a new shed (a standard pent 10'x6' with an integral floor). *I'd like to
avoid ripping up the old concrete and/or pouring too much new concrete.

Without pouring a new slab, most of the ideas I have come up with involve
building various layouts of dwarf wall either with or without an additional
2"x6" timber frame on top (in attempt to cut down on the number of walls
needed).

The problem is that with the fall on the existing concrete, I would need to
cut alot of blocks. *I'm considering the various 440mm concrete blocks and
wonder which are best in terms of suitability and ease of cutting. *Also
will it be hard to get a finished level surface building like this?
Bearing in mind my setting out skills aren't bad but I've not done any brick
or block laying. *It wouldn't be more than 1 course.

I'd be very grateful for any advice.


Shuttering and pouring more crete on would surely be the simple
option, eliminating all masonry cutting.

Pad stones, either concrete blocks, or perhaps poured in situ raised
pads, would also work, as you suggested. 2x2 floor joists are thin,
and only workable if given frequent support. Blocks, bricks & slabs of
various thicknesses are available, everything from 1" to 4". Such a
mix could much reduce your cutting needs. Pouring pads in situ would
eliminate all cutting, and the concrete needed is small enough to be
bucket mixed.


NT