Where To Tuck DPM From Under Concrete Slab?

I got a concrete slab raised above ground ready to build a summer house on with a DPM dangling out the side.

Want to put a perimeter of bricks/blocks around to further lift the timber walls above ground and allow something for me to drill the timber walls to in order to secure them to the base (don't wanna drill into the concrete slab).

I have been told I need to put the DPM UNDER the perimeter bricks/blocks, is this right?

Seems a bit weird putting plastic where mortar should stick the bricks to the concrete base? They will move about?

Or do I put mortar on both sides of the DPM as well effectively embedding it into the structure?

Here's what I got:



Also if I put damp proof course between the bricks and timber am I allowed to drill through it to secure timber to bricks?

Also is it OK to use air bricks around the perimeter as opposed to engineers etc... just cos they're easier to drill to and level? I will be cutting them in half with a grinder and laying them sideways (so around 107mm thickness).

Thanks.

ILikeDIYS said:

Seems a bit weird putting plastic where mortar should stick the bricks to the concrete base? They will move about

Click to expand...

You need dpc -it is ribbed. It needs mortar both sides to work, so put a bed of mortar down first, dpc, then another bed of mortar.

Notch7 said:

You need dpc -it is ribbed. It needs mortar both sides to work, so put a bed of mortar down first, dpc, then another bed of mortar.

Click to expand...

So a DPC under the perimeter blocks and the outside DPM will fold over the blocks (between the blocks and timber) like this?

Is there a dpm below the concrete and excess all round to fold up?

the "timber walls" are stud framings that are assembled flat on the slab and raised in one piece/wall sections.

the surface of the slab should be a min of 150mm above ground level.
you dont need blocks - roll out the DPC, and then just bolt the bottom plate to the slab - one 10mm bolt every 3 or 4 bays ( dont use a shot gun) You can even hand hammer conc nails through the sill plate.

fwiw: you should have set Simpson concrete anchors in the mix after the pour had settled - they eliminate all drilling and shooting for fixings.

ILikeDIYS said:

So a DPC under the perimeter blocks and the outside DPM will fold over the blocks (between the blocks and timber) like this?

Click to expand...

What's protecting the DPM?

^woody^ said:

What's protecting the DPM?

Click to expand...

I will admit I don't know what I'm doing but I'm rushing ahead and it's not like I'm building a real house.

So nothing is protecting the DPM. It was dumped into the hole and the concrete poured over it.

Notch7 said:

Is there a dpm below the concrete and excess all round to fold up?

Click to expand...

Not enough excess but I will add to it with double sided tape and duck tape.

bobasd said:

the "timber walls" are stud framings that are assembled flat on the slab and raised in one piece/wall sections.

fwiw: you should have set Simpson concrete anchors in the mix after the pour had settled - they eliminate all drilling and shooting for fixings.

Click to expand...

The slab is 150mm above ground at the front but below ground at the back because of garden slope.

I really don't wanna drill into the concrete as I'm worried it will crack. I was going to put the grey blocks around perimeter everywhere EXCEPT where the front door will be - because that would make the front door too high off the ground.

I was also gonna screed or self-level the floor before battening it around the perimeter and adding 50mm celotex... then chipboard floor, then laminate.



So I don't know what I'm doing with all these DPMs but the DPC under block doesn't make sense to me.