Views or advice on proposed cavity wall insulation

Mrs. Doyle

Hi All,

Just looking for some views or advice on proposed cavity wall insulation which will be

Cavity walls constructed of 100 mm block outer leaf

20 mm cavity

100 mm insulation (pumped)

and

100 mm inner leaf


Thanks.

Gumbo

Extension or new build?

Mrs. Doyle

New build

Calahonda52

Mrs. Doyle wrote: »

Hi All,

Just looking for some views or advice on proposed cavity wall insulation which will be

Cavity walls constructed of 100 mm block outer leaf

20 mm cavity

100 mm insulation (pumped)

and

100 mm inner leaf


Thanks.

How do they propose to pump 100mm and leave 20mm cavity?

What stage is this project at?

BryanF

Mrs. Doyle wrote: »

Hi All,

Just looking for some views or advice on proposed cavity wall insulation which will be

Cavity walls constructed of 100 mm block outer leaf

20 mm cavity

100 mm insulation (pumped)

and

100 mm inner leaf


Thanks.

Hi this proposal doesn’t comply with building regulation (TGD L 2017)

It’s not possible to have ‘blown’ insulation into a 120 cavity and leave a 20mm cavity. Unfortunately the post screams that professional arch involvement hasn’t happened yet.

sydthebeat

Mrs. Doyle wrote: »

Hi All,

Just looking for some views or advice on proposed cavity wall insulation which will be

Cavity walls constructed of 100 mm block outer leaf

20 mm cavity

100 mm insulation (pumped)

and

100 mm inner leaf


Thanks.

Not possible to do, also doesn't comply with regulations.

Water John

Presume the OP meant cavity board, which would be better than blown.

sydthebeat

Water John wrote: »

Presume the OP meant cavity board, which would be better than blown.

Presuming board....

A minimum residual cavity of 40mm is required for board insulation.

Its very borderline whether 100 board insulation would comply with regs.... Impossible to tell without a preliminary DEAP assessment

Water John

What is this then, with a 10mm cavity?

https://www.kingspan.com/irl/en-ie/products/insulation/insulation-boards/kooltherm/kooltherm-k106-cavity-board

sydthebeat

Water John wrote: »

What is this then, with a 10mm cavity?

https://www.kingspan.com/irl/en-ie/products/insulation/insulation-boards/kooltherm/kooltherm-k106-cavity-board

First off, we're presuming cavity board.... Now you're presuming a very specific full full board??

The OP hasn't indicated in anyway way that they are using a proprietary full full cavity board.
Of course that product can be used, as can xtratherms full fill board.

However, it would be very disingenuous to say, yeah a 20mm cavity is fine.... When, unless you use a specific product designed for full full, its not.

Anyway OP, you MUST get a preliminary DEAP assessment carried out.... It's impossible to know whether your build will comply or not.

Mrs. Doyle

BryanF wrote: »

Hi this proposal doesn’t comply with building regulation (TGD L 2017)

It’s not possible to have ‘blown’ insulation into a 120 cavity and leave a 20mm cavity. Unfortunately the post screams that professional arch involvement hasn’t happened yet.

I'm copying exact description from plans given by architect.

The exacting wording is:

Cavity walls constructed of 100 mm block outer leaf

20 mm cavity

100 mm insulation (pumped)

and

100 mm inner leaf unless where otherwise indicated

text in bold and underscore is only extra not in original description.

Water John

I presume like most, those are just, cut and paste, specs, he stuck onto the drawings. He hasn't updated them in years, or pasted an old spec.
Not unusual, have seen that before. Except, you could never pump a wall and keep a cavity. Go back to him and ask him, what spec do you need for current Regs as posters above.
Would be interested in his/her answer.

BryanF

Mrs. Doyle wrote: »

I'm copying exact description from plans given by architect.

The exacting wording is:

Cavity walls constructed of 100 mm block outer leaf

20 mm cavity

100 mm insulation (pumped)

and

100 mm inner leaf unless where otherwise indicated

text in bold and underscore is only extra not in original description.

Ok, this spec doesn’t comply

Mrs. Doyle

Thanks for those informative replies.

These are our initial plans that we are to go over and give whatever changes that we want.

Would the County Council have automatically rejected the application if it was submitted with this non-conforming insulation?

Thanks.

BryanF

Mrs. Doyle wrote: »

Thanks for those informative replies.

These are our initial plans that we are to go over and give whatever changes that we want.

Would the County Council have automatically rejected the application if it was submitted with this non-conforming insulation?

Thanks.

The CoCo won’t comment on any of this. Our building control system places all maters in the shoulders on YOU or your designers. Be careful what you accept. This is about occupant comfort as much as building regulations.

The builder in this country builds.