I had the cavity wall insulation extracted from my house at couple of years ago, as it was causing damp, probably a combination of being poorly installed and the volume of rain we get. Anyway, the damp has gone and the house is colder.

Does anyone know of any problems with external insulation? This would be the boards that they attach then render over.

Well its being done en-mass round here to housing stock with an over-render and they cant sell them fast enough.

Council are doing a lot around here as well, including some semis where the other house is privately owned and they don’t want to pay for the insulation! I’ve seen some dreadful detailing though. Its probably to early to know if there will be any long term problems as its a fairly new process.

As an aside – they’ve also done it to 11 tower blocks and been no issues I’m aware of – we work on two of them and haven’t had to do anything extra.

Its not particularly new method of insulation. On the continent they’ve used this system widely for 40 years +. Have a look at Solix or Sto for more info on available systems.

As the insulation is external, any damp will be external, so no problems. The biggest issue is fitting it to a house and making it look okay, although clearly there are different thicknesses of insulation, so thicker the better for insulation and worse for finish.

It always has on over board and a render so making it look ok is easy

Eon are going to be starting round here soon. The criteria is solid walls, but the bloke reckoned that we might still be able to get it as our cavity isn’t suitable for CWI. They’ve been doing some nearby and it looks ok from the road – my house needs painting anyway so it can only improve it 🙂

They have some excellent fake brick covering they use here to match Victorian houses, looks really good from a distance.

Not seen that, although nearly all render/roughcast up here anyway.

They have some excellent fake brick covering they use here to match Victorian houses

Sounds like “Slimbrick”.

It’s thin (10-15mm) actual brick on a backing sheet which is stuck onto the external boarding then ‘pointed’ like normal brickwork. Very hard to tell the difference between it & ‘proper’ brick walls.

You lose a bit of natural light and your view out is restricted a little – due to the wider/deeper reveals around windows. Details around the window and door openings can sometimes be clunky/awkward; also need to consider the junction between wall and roof (soffits, gutters, facia boards), the routing of external drainpipes, soil vents and suchlike, and how any vents (extract fans, boiler vents, airbricks) are dealt with.

We had our 3 bed detached ewi last year and so far so good,the house seems warmer and seems to keep the heat in longer.We had a grant for half the cost and because our house needed rendering anyway it was a bit of a no brainer.All the work is guaranteed for 25 years and the modern finishes are really good.As stated above some details around windows can be clunky but you are moving everything forward 4 to 5 inches from the existing walls.All soil pipes and water pipes are extended out where possible.

So far so good.

Thanks. I’ll have a close look at some of the others they’ve done first.

As mentioned the dew point is now on tbe outside so no interstitial condensation and eliminates cold bridging.
Unfortunately the advent of eco funding whilst commedable in reducing hesting bills has also bought a lot of installers into a competitive market and corners have been cut.
Make sure you use a reputable installer.
Whilst not as thermally efficient mineral wool is still the most stable insulation type for rendering, allows walls to breathe snd is non combustible. There have been issues with higher performance insulation boards based on phenolic or PIR due to shrinkage
Grey EPS is a good compromise between price and performance and is generally reliable.
Anything else hou need to know just ask.

If you have a cavity, external insulation is of less benefit, as you have a drafty, damp gap in the middle of your wall…..

matt_outandabout
If you have a cavity, external insulation is of less benefit, as you have a drafty, damp gap in the middle of your wall….

Surely the only issue is the gap at the top of the cavity? Good detailing will solve this and an externally insulated building lends itself to hot roof construction anyway, effectively wrapping the building?

The render is a better waterproofing material than brick so moisture control is only required from the inside rather than ingress through the external leaf. Again, good detailing at the eaves to ensure air flow.

I’d check on Navitron – they have a lot of info on there.

Just round the corner, a hybrid brick effect / render job:

[url=https://flic.kr/p/qEGZbj]External Insulation[/url] by Ben Freeman, on Flickr

[url=https://flic.kr/p/sW33zD]Untitled[/url] by Ben Freeman, on Flickr

[url=https://flic.kr/p/sDz9kk] [/url] by Ben Freeman, on Flickr