Wall Insulation Calcs

bauderline

This is my effort using BuildDesk to spec out my insulation requirements. I would appreciate comments regarding my specifications or any errors I might have made...

It's a first attempt so go easy on me !!

Baud.

bauderline

Any comment from syd, sinner et al on the above ?

Am I using this tool correctly is what I am asking...

rgs. b.

sydthebeat

i just had a quick look at the ext wall pdf.

are you cladding with 100mm of granite???
you might have shown the 25mm unvented air space as being bridged with timber battens.
any mechanical fixings for the internal PU board will not be twisted steel ties.

everything else seems fine.

sinnerboy

not bad at all B -

because K8 is foil faced you can select low emissivity settings for cavities . will give small improvement

do condensation check - I think you will see risk during summer months - insert polythene layer behind plasterboard layer - see what happens !

Are you building a basement ? - you need to watch your detailing so the insulation layers run continous from basement walls to upper level walls

Ensure your floor screed is insulated at the edges

( As always - use Homebond manual )

and - I agree with Syd's points

bauderline

Thanks lads, appreciate the comments !

Regarding detailing, it has been commented that the K8 boards don't have corner "wrap arounds" that some of the Xtratherm insulation does. Is there a method to address this ? Can the joins be foil taped again ? Is it worth foil taping all the joins in the cavity...

rgs. b.

sinnerboy

bauderline wrote: »

Is it worth foil taping all the joins in the cavity...

rgs. b.

blockies , blockies , blockies ( do i need to say more )

bauderline

lol !

sb,

Lets say that I have blockies that do as they are told... believe me you have to meet my builder to understand why I am quietly confident, taylorism is alive and well in Cavan !

It is a serious question, how do I address the issue of insulation joins at the corners if there is not a specific product for the job ?

b.

ardara1

Hi Bauder -
Just a few comments.

Wall ties I presume will not be Vetical Twist? If so 20mm x 4mm area @ 80mmsq

Cavity - foil facing on board creates a low E cavity - defaulted at 0.44R

Delta included for air gaps in board - K8 squarte edge only - gpas possible - doesn;t come with T&G jointing - which is recommended in Accredited details

Why are you going phenolic - post earlier said it was 30% more expensive?

You've a 25mm airspace between lining and insulation - is it between battens or dabs? - if so thermal bridge caused by either thru' the air gaps needs to be included. (AIrspace assume 20mm at 0.17 conductivity for dabs at 20% area)

YOu've assumend more air gaps on lining insulation - don't allow them to occur.

More vertical twist fixings - normally screws.

Remember of all you're delta factors are less than 3% of total U - they can be discounted.

bauderline

ardara,

thanks for your comments, I think I have revised the builddesk config for my walls to take account of most points raised in the posts above...

I am still curious about gaps in the cavity wall insulation and the corner detailing. Can foil taping the joints between the boards in the wall and at the corners help minimise this problem.... or is that just plain bonkers....

I am no expert on this stuff and after searching through old threads on this forum I am none the wiser....

b.