How do I construct a slabbed base for a metal shed that includes a damp-proof membrane ?

Question

Hi,

I was wondering if any one could help me, I've recently ordered an 8x6 metal shed. I need to make a base for it that includes a damp-proof membrane to avoid the well known "metal shed condenation issue". I don't want a concrete base, so I'm going with a slab base instead.

Now theres plenty of info on the web over how to lay a standard slab base for a wooden shed. And theres plenty of info on how to lay a concrete base which incudes a damp-proof membrane for a metal shed.

But I'm struggling to find info on how to lay a slab base that incorporates a damp-proof membrane so I'm looking for some info on that.

Does the membrane go between the sand/cement dry mix and the slabs ?

Won't this cause a problem as the top of the dry-mix is normally below the height of the surrounding soil (the slabs are normally slightly inset into the ground aren't they ???)

Any info or links to sites with this would be a great help.

Thanks in advance.

Answer 1

I'm a bit confused by your terminology. In my frame of reference a slab is poured/ finished concrete. By "Slabs" do you mean "Pavers"??? In either case there is always the probability that absorption will happen, leaching up from ground level. I suppose you could create a vapor barrier on top of the base, no matter that you add one to the point at which any base material also comes in contact with the soil.

  For one thing, after grading the soil/sand level you'd frame the area, lay the membrane, lay in mesh or re bar, then pour the substance.

  The depth 4 to 6 inches, need not be flush with ground level at all, and you probably should know your soil composition and frost lines. To assume that flush with ground level is "Normal" might be a stretch.

   I've never installed a shed over "pavers" using dry premix concrete to fill spaces, but I'm sure others do. Part of the issue still remains soil composition and possible settling/shifting of any type of "SLAB PAVER"

Just my two "sense"