Dry-lining necessary?

heavydawson

A few weeks out from self-build commencement, and I'm just wondering whether internal dry-lining will be needed given the following external wall construction:

100mm block | 150mm cavity with 150mm Cavitytherm Insulation (0.12u) | 100mm block

I'd like to avoid dry-lining the inside walls, but if some of the wiser folks here would recommend it (or a suitable alternative like a Quinnlite inner leaf), then I'm all ears.

sinnerboy

No one can give a definitive answer without a DEAP analysis.

Personally I would not fill a cavity with board insulation. This is a new idea and , in my opinion , the risk of damp penetration across the cavity is too great.

heavydawson

sinnerboy wrote: »

No one can give a definitive answer without a DEAP analysis.

Personally I would not fill a cavity with board insulation. This is a new idea and , in my opinion , the risk of damp penetration across the cavity is too great.

Thanks Sinnerboy.
Do you think widening the cavity to say 200mm and retaining the 150mm board would negate some of your concerns? (assuming correctly installed insulation, good blockwork, and appropriate wall ties with installation)

sinnerboy

I would opt for 200 cavity bead filled. I would run a mile from board fill. Let others be the guinea pigs.

heavydawson

sinnerboy wrote: »

I would opt for 200 cavity bead filled. I would run a mile from board fill. Let others be the guinea pigs.

If possible Sinnerboy, can you PM details of the bead you'd use (assume I'm not skimping on costs here) and any companies you may have dealt with who you'd recommend

Also, what uvalue would you expect for a 200mm pumped cavity?

sinnerboy

No. Hire a profesional to do your bidding

heavydawson

Fair enough. Thanks for the pointers

BryanF

Heavydawson, you got planning in the end? how'd it go for you? did you get the build orientated south?

heavydawson

BryanF wrote: »

Heavydawson, you got planning in the end? how'd it go for you? did you get the build orientated south?

Hey Bryan,
Yup, planning was obtained in June. Right now, I'm up to my eyes in pricing.
We've obtained a good block-layer whose work we've seen and who has experience installing the cavitytherm board we're putting in.
Right now I'm up to my eyeballs with pricing the substructure and blockwork.
I've also decided on a GSHP+UFH supplier, who has a pretty good reputation here on boards. Aiming for an A2 rating. House ended up at 287m2, sitting on a 1.25 acre site. I'll be contributing the live self-build thread once the siteworks commence in the next few weeks.

BryanF

heavydawson wrote: »

I've also decided on a GSHP+UFH supplier, who has a pretty good reputation here on boards. Aiming for an A2 rating. House ended up at 287m2, sitting on a 1.25 acre site.

jeasus 287 some manson:D best of luck with it

heavydawson

BryanF wrote: »

jeasus 287 some manson:D best of luck with it

Thanks! I'll need it :-)

fclauson

My thoughts on your process - you should

a) design
b) do DEAP or PHPP to verify your Part L and other engery demands
c) work with a QS to prep BoQ
d) IF PRICE > THAN I CAN AFFORD price go back to (a)


hope that helps

heavydawson

fclauson wrote: »

My thoughts on your process - you should

a) design
b) do DEAP or PHPP to verify your Part L and other engery demands
c) work with a QS to prep BoQ
d) IF PRICE > THAN I CAN AFFORD price go back to (a)


hope that helps

Thanks fclauson. I did follow the steps above (DEAP but not PHPP), based on plenty of good advice from the likes of yourselves here on boards.