Shed base - Should i use a damp proof membrane?

[GoffH]

I plan to build a 10 ft x 8 ft shed/workshop and have seen several possible ways to prepare the base. At present I favour using slabs on a dry mix and then placing 3 in. x 3 in. pressure treated bearers on this. Should I use a damp-proof membrane to keep the timbers as dry as possible?

[DNgroundworks]

As in under the slabs or under the bearers?

we usualy lay a couple of courses of brick with dpc and set the shed on them.

hope this helps, some one else will probably along soon to offer there advice aswell:D

[GoffH]

Thanks, I'd assumed under the bearers.

Two brick courses is another interesting method. Just to be clear, you presumably lay a cement base, then two courses of bricks, then the damp proof membrane, then the bearers. Is that correct? In that case, would 3 x 3 inch bearers be sufficiently strong for an 8 ft wide shed if just supported at the ends?

[DNgroundworks]

I dont think it makes a difference where it is to be honest as the brick and timber is going to get wet anyway from the out side.

Heres how we do it.

Pour concrete for base, build around edge of concrete with brick, then set the shed on that ( the concrete base is the same size as the shed)

If laying slabs, i would construct a foundation for the laying the brick onto, lay 2-3 courses of brick, flag the inside on to MOT, and then set the shed on the bricks.

But i think laying some dpm under the bearers if the shed is set straight on the flags will help the against underside of the timber rotting as you cant get to it in the future to repaint:D

Hope this helps

[GB_Groundworks]

sorry only just spotted this, when we build bases for timber framed stables we concrete then single corse of concrete commons. then the dpc membrane starts inside the prefabbeb panel and is lapped over the brick so any water running the wall runs off over the single brick corse.

have a look at

http://www.the-shed-centre.co.uk/buying_a_shed.html