You would expect a good contractor to understand the processes involved and inform the customer of many of these points at the planning stage.

1. Read reports on EWI failures first. (Google ‘ewi failure’ and be prepared to trawl several pages).
2. Go to British Board of Agrément (BBA) website, put in name of manufacturer of the system you intend to use and find the relevant BBA Certificate. Read what preparation may be required to make a building ready for the installation, comparing this with your property, and read how the installation should be done.
3. Involve a manufacturer from the beginning (at the planning stage), don’t rely on a contractor alone –the manufacturer will then (hopefully) be jointly liable.
4. Don’t assume that because you are employing a manufacturer “Trained” or “Recognised” contractor they will know how to do the installation properly.
5. Check if the manufacturer needs to see or draw up design plans first before your installation can be considered a ‘manufacturer’s EWI system’. In our case, we do not have the manufacturer’s sealed EWI system which we were expecting as per our Customer Agreement Form. The manufacturer said this is because ourcontractor (who actually had manufacturer trained & ‘recognised’ status) had never requested a specification or guarantee for our project and had simply chosen to purchase their materials. Our contractor eventually said that the manufacturer would guarantee their products & they (contractor) would guarantee their workmanship (!!).
BUT –we have nothing in writing which also means that our 25 year ECO guarantee is not valid.
6. Don’t assume that, even if the manufacturer says everything taken off your house is put back after, that it will be. Take photographs to ensure they put things back in the right place. Write everything down individually and get them listed in the contract–gates, satellite dish, hanging baskets, fences, outside lights, electric wiring brackets etc.
7. Check your roof overhang. EWI boards may jut out beyond the roof edge relying on silicone to seal the top of the system but reports now say it’s preferable for a roof to cover the top of the EWI.
8. EWI seems to block the natural air flow to your loft at the soffit, make sure they install soffit vents or you will risk excessive condensation in your loft. (Lack of soffit vents caused extreme condensation in our loft).
9. Make sure your house is in tip-top condition before the installation, you may not be able to access parts of your house for maintenance afterwards. Check all flashings, adjoining flat roofs, windows, doors etc.
10. Ask for a specimen of the warranty/guarantee to check the terms and limitations, otherwise you probably won’t get to see this until the job is finished. It may limit your cover to the original cost of the installation and you may have to have the same contractor back (which is no use in a case like ours).
11. Make sure your household insurance covers you for such work –especially cover for legal costs if things go wrong (otherwise you’ll need a spare £50-60,000 to have the job put right or cover the cost of taking the contractor to court).
12. Be aware that once EWI is on your house you may not be able to lean ladders on your walls to do any maintenance work (e.g. gutter clearing, window cleaning). BT will have to come with a cherry-picker to do any work. (We were told by a Power company workman that, in the Welsh Valleys, kids have punched holes into the EWI and used them as climbing walls).
13. If things go wrong NO OTHER EWI COMPANY will touch it –we know of others who also found that this applies.
14. In our experience the trade associations offer no protection to the consumer and appear biased towards the contractor and manufacturer.

This list is not exhaustive.