Concrete slab for outbuilding

mpooley · 28 Nov 2006

Hi
This is my first post here so here goes

I am building a timber workshop with a Clay tile roof so will be fairly heavy.
I have a lot of rubble left over from demolishing old outbuilding so my question is:
what depth of rubble (it will be rolled by large vibrating roller) any blinding?
locally we use hoggin which is sandstone. and will 100mm of concrete be enough?

The soil is a loamy clay with a clay subsoil. I have LOTS of rubble so was thinking of 200-350mm of rubble

also for any experts out there! I have some old steel reinforcing mesh - not enough to do the whole job - should i leave it out or put it in? and does anyone know what concrete mix i should use?

Thankyou

Mike

noseall · 28 Nov 2006

do you intend to cast a concrete slab upon which you wish to build the structure?

if so 100mm is no where near thick enough. you will need to thicken and reinforce the perimeter (called a toe beam) in order to support a wall and roof load.

mpooley · 28 Nov 2006

noseall said:
do you intend to cast a concrete slab upon which you wish to build the structure?

if so 100mm is no where near thick enough. you will need to thicken and reinforce the perimeter (called a toe beam) in order to support a wall and roof load.

OH!

how deep should the perimeter be then do you think?

thanks

Mike

masona · 28 Nov 2006

More info on www.pavingexpert.com

Tozzy · 28 Nov 2006

masona said:
More info on www.pavingexpert.com

what the hell! How come they don't make houses like that? I bet that's hard to do

.

noseall · 28 Nov 2006

Tozzy said:
masona said:

More info on www.pavingexpert.com

Click to expand...

what the hell! How come they don't make houses like that? I bet that's hard to do .

they do make some houses like that.

mpooley · 29 Nov 2006

OH Dear

That looks hard!! and expensive!
Dont forget i've got large amounts of rubble to get rid of in this slab.
I wouldnt need all that on top of of a foot of compressed rubble surely?

why do i need 150mm of slab as well as the perimeter its only light machinery ?
also doing it that way would be difficult because of all this rubble i've got.
if i dig a perimeter trench and fill it with rubble the roller will be too wide to compress it. so i would have to dig the whole thing say 200mm deep and then an extra say 200mm at the perimeter fill that all with rubble and roll it.
fix shuttering in place; pour the footings, wait till that went off and then as i wouldnt have any more rubble lay hoggin in the centre and then pour the slab.
does that sound ok? or has anyone any simpler ideas? please?

Thanks all
MIke

masona · 29 Nov 2006

mpooley said:
I am building a timber workshop with a Clay tile roof so will be fairly heavy.

You can get away with 100mm base but will need a footing round the edge to take the weight of your clay tile roof.

I didn't bothered using clay tiles on my summerhouse roof because of the weight so I've use the metal tile effect sheeting which is very light.

mpooley · 2 Dec 2006

masona said:
mpooley said:

I am building a timber workshop with a Clay tile roof so will be fairly heavy.

Click to expand...

You can get away with 100mm base but will need a footing round the edge to take the weight of your clay tile roof.

I didn't bothered using clay tiles on my summerhouse roof because of the weight so I've use the metal tile effect sheeting which is very light.

BTW how does the roof look? I've never seen the tile effect in the flesh does it look good?

Mike

masona · 2 Dec 2006

Read here for the Metal sheet roof supplier

mpooley · 2 Dec 2006

Thanks

That looks good!

I'll just have to show the Mrs see what she thinks.

Mike

oilman · 4 Dec 2006

You are building a wooden shed, so it has clay tiles on top. How big is the shed? Think how much it weighs and work out how much pressure you'll have on the ground. 300mm thick?????!!!!!! what are you going to build??? It's only a shed, you could support it on 100mm blocks (like I did with mine) I made the floor from scaffold boards. Go to www.readersheds.co.uk

mpooley · 4 Dec 2006

oilman said:
You are building a wooden shed, so it has clay tiles on top. How big is the shed? Think how much it weighs and work out how much pressure you'll have on the ground. 300mm thick?????!!!!!! what are you going to build??? It's only a shed, you could support it on 100mm blocks (like I did with mine) I made the floor from scaffold boards. Go to www.readersheds.co.uk

to be honest thats what i think too!
but i did ask! and i'm not an expert.
I have built another large shed 30ft x30ft on a 4 inch slab but that was with a steel roof and was on very good subsoil eg Gravel.
If i had the same soil here i wouldnt worry but i'm not sure!!??

The shed is 15mtrs long by 5 mtrs wide.

Mike

oilman · 5 Dec 2006

Do you want a concrete slab? At that size I accept you have a risk of cracking if it's in one piece unless it's thick enough. If you had a wooden floor there's not so much of a problem. Using styrofoam slabs under the floor would be another thought.

mpooley · 5 Dec 2006

oilman said:
Do you want a concrete slab? At that size I accept you have a risk of cracking if it's in one piece unless it's thick enough. If you had a wooden floor there's not so much of a problem. Using styrofoam slabs under the floor would be another thought.

well I am going to use jablite under a floating floor of chipboard anyway so what are you saying exactly?
do you mean having a concrete footing all round and a suspended wood floor on joists or do you mean just lay the DPC onto hoggin in the centre with the jablite on top and the chipboard on top of that?
cos i have thought that with 8inches of rubble and 4inches of compressed hoggin on top of that why do i need a concrete floor ?

Mike

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Concrete slab for outbuilding

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