Foundations - strip or raft

[b21playa]

Building a shed/store in the garden (30sqm) out of 6" solid concrete blocks.

What would be better strip or raft??

There is already some bit of a raft from the base for an old shed

 

[noseall]

strip every time for me.

rafts are nowt but trouble.

 

[b21playa]

strip every time for me.

rafts are nowt but trouble.

im digging 800mm down, how much should concrete be?

 

[noseall]

im digging 800mm down, how much should concrete be?

cost or thickness?

you will require a minimum of 225mm thick concrete though economically it is sometimes better to mass fill.

i thought you would be further on by now playa.

 

[b21playa]

im digging 800mm down, how much should concrete be?

cost or thickness?

you will require a minimum of 225mm thick concrete though economically it is sometimes better to mass fill.

i thought you would be further on by now playa.

LOL noseall;

Things just have'nt gone my way. Been so busy with work and messed around by people - getting ridiculous.

Finally managed to get someone to move the 1000 blocks to the rear for £50 - its a start

Today i managed to cut the old slab with a disc cutter where it is in the way for the trench.

Actually the brickie I got doesnt mind mixing up the concrete, what would be the cost for 225mm thickess x 450mm wide x 22m long be to buy materials???

 

[noseall]

it will take a little under 2.5m3

you will need 5t ballast and 33 bags of cement.

average cost (trade) about £295.

 

[b21playa]

it will take a little under 2.5m3

you will need 5t ballast and 33 bags of cement.

average cost (trade) about £295.

what the price of ballast and cement by you, i got it to around £260 retail

 

[b21playa]

Finally started the digging, should be done tomorrow. Then just need to order the concrete and level it out to start blocking up to dpc

 

[noseall]

Hoorah!

 

[JohnD]

strip every time for me.

rafts are nowt but trouble.

OOI, what's wrong with rafts?

(I am used to deep clay soils)

 

[noseall]

all that re'bar and stuff John, too much fuss.

 

[b21playa]

@noseall,

After pouring the concrete, and building up 3 rows of blocks (220mm above ground), do I just use a dp membrane on the floor and over lap it over the block for the dpc or do I have to use seerate dpc for blockwork?

Also what thickness should the concrete floor be ontop on what thickness hardcore? Its only to be used as a shed and no vehicles

Thanks

 

[noseall]

lap the dpm onto the blockwork plus a dpc layer on top.

floor spec: 100mm trowel finish slab on 1200 gauge polythene dpm on 100mm (min) compacted or rolled mot type 1 (30mm-dust).

 

[b21playa]

lap the dpm onto the blockwork plus a dpc layer on top.

floor spec: 100mm trowel finish slab on 1200 gauge polythene dpm on 100mm (min) compacted or rolled mot type 1 (30mm-dust).

Any chance of a quick diagram to show dpc

Also for 30sqm, 100mm thick, how many tonns of hardcore is required?

 

[noseall]

about 3 tonne.

sorry no diagram.