Breather membrane below dpc - big no no?

endecotp · 24 Feb 2018

CB76 said:
I was thinking about using 30mm insulated plasterboard which runs all the way up to the ceiling. I'm not sure about the effectiveness of the 30mm insulated plasterboard compared to having a thicker insulation in the timber frame

30mm of polystyrene will be roughly half as insulating as 100mm of mineral wool in the studwork.

Mineral wool would also be a better acoustic insulator, if that matters to you.

I'd fit both. Or if you don't want to do that for some reason, fit polystyrene (or PIR etc) over the blockwork, then extend the studwork with battens of the same thickness (or maybe just use thicker studwork timber, overhanging the top of thr blockwork???), and board over all of it.

CB76 · 24 Feb 2018

Hi,

Thanks endecotp. I was thinking about putting insulation in the frame as well. That's an interesting idea extending frame to be flush with block wall foundation. I will look into which is the most cost effective.
Thinking about loft insulation in walls as much cheaper but not sure if it would work along side the plaster board insulation?

Cheers

endecotp · 24 Feb 2018

CB76 said:
Thinking about loft insulation in walls as much cheaper but not sure if it would work along side the plaster board insulation?

It would be fine. The one thing that doesn't like contact with polystyrene is electrical cables.

CB76 · 24 Feb 2018

Hi,

Would it be okay to fit the 100mm loft insulation into the 100mm frame or does there have to be a gap in there somewhere? Concerned about the insulation touching the osb boards

Cheers

^woody^ · 24 Feb 2018

no gaps no voids

CB76 · 12 Jun 2018

Hi,
About to put timber frame up on breeze blocks and thinking about not including the foam insulation to cover the two courses of breeze blocks and just having insulation in the timber frames. Would it be ok if plasterboard touches the dpm which goes up the wall to links in with the dpc? And if yes would I need to use moisture resistant plasterboard?
Forgot to mention I was going to put vapour barrier between wall and plasterboard

Nige F · 15 Jun 2018

^woody^ said:
Here is the principle.

BTW, building off hardcore will cause the building to settle and move. More so of that hardcore is soaked by a drain.

Woody, I recall "reject ballast" like cobbles ? being used instead of hardcore to avoid settlement. Is it still about ?

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Breather membrane below dpc - big no no?

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