External wall Insulation

The green grant scheme are now offering us external wall insulation. We are small victorian semi and we don’t want the whole house wrapped in EWI.
Not only would it spoil the features on our home - we have a lean to kitchen extension with cavity wall and wonder if it is okay to mix cavity with EWI
Also, we wondered if it is beneficial to get just the gable end - side - of the house completed in EWI .

Any thoughts or knowledge to share ?

Many Thanks

You raise 3 points, which I will try to address.
a) Appearance. EWI can be covered in brick slips to simulate the original building. The grant may not cover that.
b) Cavity walls. If the cavity is already fully filled then that isn’t a problem.
c) Partial EWI. It can be done but has little benefit. The junction between EWI and IWI needs to overlap by about a metre to avoid thermal bridging. I would only suggest it if the majority of the house is getting EWI and the IWI it to preserve a particularly important architectural feature.

I agree that there could be particular circumstances where EWI can be applied selectively. As Eon have now completed the technical survey for my house, I expect them (or rather, live in hope!) to confirm a start date shortly. However, like you, I am wary of agreeing to having all of the external walls clad.

The problem that I found is that it is not easy to reach a human being, as (surprise, surprise!) they appear to be taking a tickbox approach to the process.
I also do not understand why, unlike the earlier (failed) central govt scheme, internal wall insulation is not an available option - For a mid-terrace house like mine (south facing and almost opening on to the street), IWI in the master bedroom and in the front room would arguably be 80%+ as effective and, the house already in a state of renovation, would cost them less to install.

Anyway, I don’t know if any of this experience will be useful to you, but it at least cathartic for me get it down!

Hi Tom :smiley:
your experience is very much useful for me to hear. We share very similar thoughts.
I had two examples of properties sent to me that are gable end houses. They each have EWI on the gable end and then IWI at the front and back leaving the Victorian facades looking as lovely as ever. The two insulations overlap inside to outside. The houses have biomass boilers, solar panels and double / triple glazed windows. Each home had significantly reduced their energy and carbon consumption. One is Chorlton and another in Nottingham @lloydham shared them to me to take a look.
They are on SuperHomes here - https://superhomes.org.uk/meet-the-superhomers/
Take a look.
Also, I had progress via Eon today as well - a man who looked like a robot came to our house :sweat_smile: - to scan it !!!