Raft Foundation Detail

Hurler85

Hi,

Just got raft foundation details back off my engineer for new house build. I see the radon barrier is called up over the concrete slab of the raft. While I see it’s a common detail, doesn’t l this mean that the membrane is exposed until floor insulation is put down which would mean risk of puncturing from construction works? Would it not be better to place under concrete and eliminate this risk? TIA

Biker1

Hurler85 wrote: »

Hi,

Just got raft foundation details back off my engineer for new house build. I see the radon barrier is called up over the concrete slab of the raft. While I see it’s a common detail, doesn’t l this mean that the membrane is exposed until floor insulation is put down which would mean risk of puncturing from construction works? Would it not be better to place under concrete and eliminate this risk? TIA

It would be rare to not have it below the concrete for the reason you stated.

rayjdav

http://www.necoflex.ie/support/radon-barrier-solution-finder/ram-system/design/construction-detailing/construction-detailing-05.aspx

Exactly the same issue with any build type, membrane exposed until last minute.

Bullocks

The last time we didn't put the radon barrier under the concrete we put strips of radon under the blocks when building then when we were ready to put down the screed we cleaned out everything off the strips, put on the mono bond radon tape allowing for a good lap and put down the floor/room sized pieces over the strips

P2C

My builder built a block on the inner leaf, added the floor insulation directly on top of the radon barrier (150mm) on the slab. Put a trim of insulation 1inch x 100mm around the perimeter and then poured the finishing slab 100 mm of concrete to the top of the insulation trim. Very easy to power float and nice smooth/ slab finish. I don’t have underfloor and it’s a domestic garage.