insulation between brickwork and timber frame.

[ALAN/ALAN D]

Hello Ladies / Gents.
My timber framed house with external brickwork can not have any insulation in the cavity between the the brickwork and the timber building. ?
Why is there no insulation available for this type of building. ??
Yes I have got lots of foil backed insulation in the internal void between the wood and the plasterboard.
If the cavity was filled you would not hear this wind blowing about outside.

[Joeboy]

Moisture and airflow agree that there should be something but I think it is externally cladding the home in insulation then render.

[Mr Gus]

So are you saying no tyvek (type) breather membrane was ever fitted? which should be standard & allow you to stick PIR foil faced slab underneath?(then I looked again & saw the word "brick" ..so now i'm confused)
Is it all single skin top to bottom or dwarf walls?

[ALAN/ALAN D]

By the wording you can tell I know nothing about building.
The timber framed house was built 20 years ago. It had an external grey felt material on all the outside wooden panels. Then the external brickwork was built with a cavity between the brick and the timber frame. I put two lots of 50mm foil backed insulation between the internal wood frame and the plasterboard. I was told that no insulation can be fitted between the outside timber frame and the brickwork in the cavity.

The picture is of the rear of the house.
I did ask a company that was drilling holes in the brick built bungalow next door and pumping insulation into his cavity if it could be done on mine. He said there is no suitable insulation for filling a cavity between brick work and timber frame. ?

[Moxi]

From everything I’ve ever heard regards timber framed and brick dressed facia walls and a from living in one with my parents through the 80s into the 00’s I know that the normal remedial insulation options are internal and external wall insulation systems.

Mortgage companies are acutely aware of timber framed properties and the damage that can be caused by cavity wall insulation being installed later in the life of the building and they will generally not offer a mortgage on a timber framed building that’s has got cavity insulation as far as I’m aware.

Having got EWI I can thoroughly recommend it but again after recent reporting on external cladding systems even this can hamper future consideration for selling etc so you need to be ultra careful with your options and final selection.

Moxi

[Mr Gus]

By the wording you can tell I know nothing about building.
The timber framed house was built 20 years ago. It had an external grey felt material on all the outside wooden panels.

Look up "tyvek house wrap" to get an idea of what you have (insight) & its uses / limitations.

https://www.dupont.co.uk/products/tyvek-housewrap.html it has gone through various changes over time.

Question to ask is how does all that change if you have a multi room ASHP keeping moisture down, a modern twist on wet rads & the atypical permanently shut windows of modern homes where plasterboard go's black through lack of ventilation from breathing cooking, gas flame / gas heating etc..

ASHP (& the moisture control it enables) may put a spin on construction types that need to be reconsidered, not my area of knowledge though, others will be able to comment I'm sure.

Maybe have a chat to the developers / owners of "Wyboston lakes" (St neots / eaton socon Cambs / Bedford border area) who have had this since the mid 1980's as to what their maintenance team have done over time to improve the timber frame & brick clad complex. (ie what works & what not to do)

The area is owned / developed by "potton homes" https://www.potton.co.uk/ ..an early days "drop in" pre-made sips firm across the road, still going, possibly your home too? Head office: 01767 676400

[Countrypaul]

When we renovated our current house, we opted to use SIPS based on the architects reccomendation. The SIPS were used for almost all the roofs (175mm with 150mm PUR core) and new walls abour 50% of external ground floor along with both gable ends of a dormer bungalow walls 125mm witha 100mm pur core. The outside was then given a brick skin and cavity wall insulation injected into all the cavity walls (cavity about 70mm) both brick/brick and SIP/Brick. The full brick walls were also internally insulation with 50mm of rockwool. On extension at the rear of the house (single story) has 125mm sips with 50mm EPS and a trough colour render externally. All walls are battened 25mm for SIPS and 50 with rockwool for brick inner leaf (to allow services) then covered with plasterboard and skim. The first floor has open webbed joists which allows for easier installation of services, all first floor walls are Wooden stud, nearly all ground floor walls are brick other than one with pocket doors, one for a cupboard and one between lounge and study.

The CWI was inject from the inside before PB was installed to hide all evidence of installation.

Heating is by UFH driven by an ASHP and the house also benefits from an MVHR system - we have never seen any black mould on the walls anywhere.

Most North facing windows are tripple glazed and the rest double glazed, we tend to open windows very little as not needed for ventilation.

[Mr Gus]

OP.
MVHR = Mechanical Ventilation heating recovery. (to fill in any gaps you may have)
https://www.paulheatrecovery.co.uk/mvhr-guide/

[spread-tee]

Brick clad timber frames do need the cavity ventilated because a single skin brick wall is not water-proof by a long way, and whatever does penetrate would have very difficult time to disperse away from the building if the cavity were filled. You will have a breathable membrane (Tyvek) on the cold side of the timber that is designed to let vapour from within the timber wall disperse through the cavity also. If you want to increase the insulation you are best off installing on the inside.

Desp

[Stig]

Brick clad timber frames do need the cavity ventilated because a single skin brick wall is not water-proof by a long way, and whatever does penetrate would have very difficult time to disperse away from the building if the cavity were filled. You will have a breathable membrane (Tyvek) on the cold side of the timber that is designed to let vapour from within the timber wall disperse through the cavity also. If you want to increase the insulation you are best off installing on the inside.

Desp

That was my understanding too, living in a 1980's timber frame brick 'clad' house.
@Alan, if you've replaced the mineral wool with PIR then I think you've done all you can for the walls without adding IWI. All I've done is increased the loft insulation from the original 100mm to 100+180mm, I find the uninsulated concrete floor and drafts to be the biggest issues comfort-wise. Difficult to do much about either of those without major disruption (gas-fired heating fed by internal air roughly in the centre of the house).