paper igloo architecture and design

Airtightness at the ground floor perimeter

February 22, 2015

This weekend we completed the airtightness at the ground floor perimeter and the ground floor slab service penetrations.

The ground floor junction is made airtight using DA-S roll, which is a membrane that is suitable for connecting structural components which experience short term exposure to humidity. Here are some photos of the process...

Firstly I had to clean the concrete floor to eliminate any dust; I then primed a band of the concrete using Tescon Primer RP (another Pro Clima product) to make sure that the Orcon F airtight glue will stick properly (which you can just see as a darker band next to the wall). Once the primer was dry I laid out the DA-S roll and stapled it to the Spano Durelis boards with two rows of staples, one at the top and one at the bottom, to make sure that no part of the membrane was fixed further apart than 100mm.

I folded the membrane as I went to make sure it didn't stick out into the room further than 45mm so that it wouldn't stick out beyond our service cavity batten, as the concrete is our finished floor surface, and we are going to have a 10mm shadow gap at the base of the wall instead of a skirting board.

   

I then applied a decent sized bead of Orcon F to the concrete floor and lightly pressed the membrane down onto it, taking care not to squash it flat.

A movement joint was created by pushing the membrane back into the corner junction between the slab and the wall, to allow for any future movement of the frame. The top of the membrane was then taped to the wall board, and I taped over the staples as well, as we did everywhere else. 


At the reveals of the doors we had to work around the tie-down straps which will be in the service cavity zone as it turns round in to the door itself.

The membrane was turned around the corner into the door reveals...


A good bead of Orcon F went down first...


I had to make sure that this connected fully to the airtight membrane and tape coming down from the door frame itself to make sure there is complete continuity of the airtight 'line' around the building perimeter...


As the membrane turns the corner I made a relief cut which consequently leads to a small section of membrane missing...


Which was covered by some Tescon Vana...


Finally, the DA-S membrane was taped to the tape on the door frame and the Intello membrane in the reveal.


We also have one point where the main BT cable comes through the slab right at the wall edge (a little more tolerance on the setting out here would have helped!) so I used another Kaflex cable grommet here for simplicity and certainty of achieving airtightness instead of using more tape and glue! (Although the grommet protrudes beyond the service cavity zone we have a bench seat here that will conceal this.)


After the perimeter was done, I tackled the slab service penetrations, which consisted of 2 cables (coming up through the slab in 50mm diameter ducts), our mains water pipe (again in a duct), and 2 soil pipes.

Firstly I cleaned the soil pipe with some sandpaper as it had quite a lot of cement on it from the slab pour....


Once the grommet was in place I could mark out on the floor the outer edge...


I then added 30mm so that the 60mm wide tape could be half on the grommet, half on the floor...


I then primed the concrete...


Once the primer was dry a bead of Orcon F went down...


The grommet was then stuck down to the slab...


Then the edge of the grommet was taped to the slab for good measure!


The other soil pipe...


 

Finally, the mains electricity cable and the pumping station cable (with the earth cable from the slab reinforcement also coming through the edge of the grommet, hence the Orcon F here!).