Broadback wrote:
Harry Bloomfield wrote:
Broadback wrote :
Is it worthwhile installing a damp proof membrane when I build a
concrete base for a metal shed? The concrete base will be the actual
shed floor.

I would suggest yes, but you also need to consider how you intend
shedding the rain which might run down the outside walls and then
track into the shed along the concrete base.

Thanks for all the tips, a membrane it is then. The manufacturers
recommend sealing the base to shed with mastic to stop ingress of
water from the outside walls. Also the base will be about 10cm longer
and wider than the shed,

If rain is falling on the external concrete, it will still soak through the
concrete mass and dampen the whole slab. You might wish to either add a
waterproofing additive to the concrete mix, or else saturate the external
apron with Thompsons WaterSeal or similar.