One issue I have with cost plus is the cost bit. On this basis, the builder has little incentive to find the best price for materials and (as I have discovered) this can vary tremendously. Instead they go to where they usually go as it is easier, but not necessarily cheapest. I'd add something to the contract so that any material purchased over a set amount requires 3 quotes to substantiate the invoice.

Posted By: borpinOne issue I have with cost plus is the cost bit. On this basis, the builder has little incentive to find the best price for materials and (as I have discovered) this can vary tremendously. Instead they go to where they usually go as it is easier, but not necessarily cheapest. I'd add something to the contract so that any material purchased over a set amount requires 3 quotes to substantiate the invoice.

I agree , this is likely , but if you're paying for thier time, what may seems a cheaper material may end up more expensive if to much time is spent tracking done the bargain .
I use a more expensive builders merchant over the local BQ trade as I can get in and out quick , load the van next to the material ( plus free bulk delivery organised over the phone etc) for other stuff it's hard to beat screwfix/toolstation for an efficient competive way to get your materials on site with little effort and time wasting.
On the small jobs I do , it's good to set the client some home work , tracking done the bargain after pointing them in the right direction , then it's thier time rather than them paying me.

I think it would be good if all installers of insulation where required to supply a thermal image of the property after the work was done. OK, it's a bit late to find out there are hidden gaps but it would make people more conscientious if they knew it was going to be measured and it couldn't just be covered up.

If an installer offered me that - perhaps a before and after photo - I'd be inclined to trust them.

So yesterday I got a call from British Gas, asking me whether I would be interested in loft insulation and/or cavity insulation.

I tell the lady, and then her manager, that I have solid walls, and therefore would be interested in EWI.

"We don't have nothin' to do with that. We only do cavity wall insulation."

So I asked, "Could you put me in touch with the department at BG that deals with EWI? I see that on your website BG does offer this as well."

"No, we only do cavity wall insulation."

...So I do some digging and find the number at BG for this myself. I speak with a very helpful lady in a very quiet office : the Solid Wall Insulation Team.

She informs me that my house would probably cost about £14k to insulate externally, and that through BG I could probably get about £1.8k toward that expenditure, but all the work would have to be completed this year.

Probably not a practical/real option then, given that I haven't initiated anything formally yet (and we're already half-way through September).

Having seen the video linked in a related thread, of 'professional' EWI installers, I'm somewhat concerned that EWI is likely to be both expensive *and* haphazardly fitted!

Posted By: ikimikiI speak with a very helpful lady in a very quiet office

Can I have number as I would like a job with little work

Posted By: Jontiwould have thought photos would be a very good idea as they could be downloaded and e.mailed to all concerned daily at low/no cost. Anything of concern could be dealt with straightaway. I would have thought that thermal imaging would be an extra cost, be after the horse has bolted and would show things up better in winter than summer.

and it's a lot of work to fix after you've rendered and taken the scaffold down. And phones with high res video are common - an alternative to lots of photos.