EWI trims - opinions wanted

Hi all,

Once again I'm looking for some informed opinions from you knowledgable folks. I'm currently having EWI fitted and this is what's been done with the trims under the dry verges on the gable ends.



I'm concerned but keep being given assurances that this is all totally acceptable - I've got some ideas as a layman as why it isn't right, but wanted people to take a look and form their own opinions.

'acceptable' or not, that's awful, the only way to sort would be to extend the roof out over the EWI

These company's fitting this stuff seem to think anything is ok and that nobody is supervising there work.

They're trying to say that it'll be water tight by the end but I can't see how - there's gaps to the joints in the trim, the trim isn't straight and is bent down exposing the EWI behind (apparently done to defy the laws of physics so the water runs of the edge and not down the slope?)

Both those are surely going to lead to water getting behind it and, if it doesn't cause damp, is likely to freeze and cause the render to pop off?

Then there's the issue of the trims not running into the gutters. I don't fancy a waterfall feature to the sides of the property every time it rains.

I had EWI done last year. They did it the same, but they slotted in additional bits of trim under the two longer pieces to join them up. Building control made them fill the gap behind with mortar (on my house it meets the roof tiles).

It's not ideal, they certainly do whatever they like as long as they're not being watched. There were some bits I had them redo as they had angled the verge trim back toward the wall so it would have actively directed rain behind the insulation. Completely awful.

The company that's doing it? Don't begin with 'M' do they?

I know who you're thinking of (it rhymes with Bark Coop) but it isn't them. This is a local firm that does masses of work in the area and have been around a while.

I chose them because I'd seen a lot of their work and it looked pretty tidy, so I thought I'd be well clear of straying in to Cowboy County. However for some reason they're making a pigs ear of this one IMO.

Yeah.. or 'Shark soup'.

In any case my advice would be to press hard now to get it to a standard that you're happy with and have them explain exactly how they plan to make it watertight. It is much easier to fix it now than when it's rendered. I'll bet their plan is to fill it with Silicon, which will be fine for a year or two but is probably very awkward to renew in future due to difficulty of access.

On my place they made a pigs ear of the window sills. Blocked all the drainage channels, which I foresaw.. they kept saying 'it's fine, don't worry, we'll put face drains in'. Of course that didn't work since my windows had concealed drainage and any water poured into the frame ran straight past the face drains and into the insulation.

Cost me an additional £1500 to put it right after the initial installation with an independent window contractor.

The correct original solution would have been to use under sills, not over sills.

Based on my experience, places to watch our for are:

+ Detailing around windows, doors, flat roofs or any other interruptions to an elevation
+ Verge trims as you have already spotted
+ Window drainage channels - make sure they won't be blocked
+ Reinstatement of rainwater goods, mine went back on all wonky
+ Ensuring any screws they put in the insulation have appropriate fixings into the substrate if necessary. Ensuring seal around screw with blob of silicon to prevent water ingress behind
+ Decent sealing around wastepipes, etc where they exit through the render
+ Making sure that any extensions necessary to wastepipes are done internally if possible. On mine their original plan was to use a worm-thread rubber coupling to extend waste pipes and bury it in the insulation. I convinced the plumber to extend the pipes internally, but I had to lift a few floorboards for him to do that.

One other thing which has changed since mine was done is the insulation below DPC. When mine was done this was not standard practice for fear of bridging the DPC. However I think that has changed now and best practice is to install polystyrene to some depth below ground. This'll keep your skirting boards inside nice and warm and prevent any cold spots.

There is a good guide to best practice and common shortfalls in this doc:

http://domestic.sersltd.co.uk/wp-content/uploads/BRE-White-Paper.pdf

Pretty much all of the 'mistakes' in this doc were made on my place.

Thanks, that's all useful stuff.

I'm going around in circles with them at the moment as they refuse to alter the work (you'd swear they were the ones paying for the job). I'm sort of resigned to just letting them do it and if / when it fails falling back on the insurance backed guarantee I'll be getting to have someone put it right.

Not really happy with that, but seems the best way to stop them dithering and get things moving again.

You have bigger problems than the trims at the moment. Why are there no hammer fixings in the GEPS boards? I know of no BBA certified system that is simply glue fixed and structural adequacy is determined by the hammer fixings, the adhesive does not form part of those calculations.
Ask what system they are using and further ask who has designed the system? Is it covered by a SWIGA guarantee? (Not if it isn't a BBA certified system!)

The pictures don't show it but the fixings have been put in.