DIY Doctor UK DIY Forums

I am about to place a small shed in the back garden.

The garden fence is the lapped 6ft wooden panel type with concrete posts and moulded concrete bottom cross-pieces.

As the shed is going in the corner is it feasible to constuct wooden shuttering for two sides only and use the existing fence concrete cross-pieces as the other two sides for shuttering a concrete base?

g30rge,
Yes but it may be worth putting timber shuttering against the concrete gravel boards especially if the fence is not yours.
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Thanks for the reply.

I thought after posting that i'd probably need to put some shuttering like you say but only so i've a level to tap along with a straight edge.

Why though would it be an issue if the fence wasn't mine?

I think it's shared boundaries but i seem to have got the backsides of the gravel boards on all three sides!

g30rge,
If you cast direct onto the gravel boards and there is some issue with the fence at a later date guess who will get the blame? Cast the base so there is a definite gap and you should not be held liable.
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Aagh, great point, thanks.

Is the shuttering normally removed after concrete sets?
Then i could get the shed pretty close to the fence.

g30rge,
It won't matter - chances are it will rot away over a period of time.
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yeah, think i'll leave it in place to hide the base - the slope on the garden means the house facing edge is fully displayed.

I've now completed the shuttering, in place of a sub layer i've used old breeze blocks and various bits of broken blocks and general rubble.

Google "yfrog.com/2sdscf1245j

My query is should I now get the concrete down or continue to try to fill the gaps between the blocks with smaller and smaller rubble?

Or should I brush some sand down the gaps, if so which type?

"i've used old breeze blocks and various bits of broken blocks and general rubble."

If you've broken up the blocks then it should be OK but should be well compacted. How deep is this layer? The whole sub-base should be around 5 inches deep. A layer of scalpings over the top (well compacted once again) wouldn't hurt and once you've done that a blinding layer of sharp sand isn't a bad idea. You should also lay a 1200 guage polythene DPM on top. This will stop the sub-base drawing the water out of the concrete too soon and prevent moisture rising up into the fabric of the shed and its contents later on.

Cheers

Hi,

The sub-layer is about 4" - the tickness of the breeze blocks, leaving about 4" for concrete.

Not sure why link didn't work last time, here's a picture:

Google "yfrog.com/2sdscf1245j"

I wasn't going to put a dpm, but that maybe a good suggestion.

g30rge,
Concrete straight on your prepared base adding any additional layers will only give something for ants to live in ( and rats if you make it deep enough). DPM will have little effect on the dampness in a shed - I wouldn't bother unless you are going to seal the inside and live in it.
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