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Housing - Renovation: EWI vs IWI thoughts & supplier recommendations

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  1.  
    • CommentAuthornbishara
    • CommentTimeJul 3rd 2021
     
    Hi all,

    I've thought about the above for too many years and I'm now just wanting to abandon my perfectionism in favour of pragmatism and a warmer house.

    Does anyone have a recommendations for EWI installers because we were underwhelmed by most of their websites (more emphasis on colour than U value and no eaves detailing etc)? As implied, I think I'd be better off with reasonably installed standard EWI with cold bridging, than any amount of hypothetical woodfibre, fly past detailing, windows in the EWI that I probably couldn't afford and won't get round to doing (great though it might be). Basically I want to get someone to just do a reasonable job at a reasonable price. Its a small semi detached and would require front and side and I'm pretty sure that I was last quoted 30k which seems mad.

    I have gone back to considering IWI, despite it's evident drawbacks. I wasn't going to consider it because my house is small, but then my partner knows someone who's used aerogel and the price has apparently come down. He did it himself, but any thoughts or experiences of self install of aerogel or installers would again be really appreciated.

    Thanks for any help anyone can offer; I'm driving myself crazy with my own procrastination (& my partner;-)

    Tania
    • CommentAuthorSimonD
    • CommentTimeJul 3rd 2021
     
    I'm about to go out so just throwing this out there for now. Have you looked at INCA database for EWI installers? https://www.inca-ltd.org.uk/find-an-inca-member/

    Might be worth a try and at least you have a better chance of finding someone who knows the detailing requirements of good EWI, even with existing windows still in place :smile:
    • CommentAuthorRobL
    • CommentTimeJul 3rd 2021
     
    Ewi store have upfront materials price, and a list of approved installers. Install costs will usually dominate. They have eps, rockwool, wood fibre, with lots of thicknesses.
    •  
      CommentAuthordjh
    • CommentTimeJul 3rd 2021
     
    Posted By: RobLEwi store have upfront materials price

    On a quick look, the prices don't look very good though? One-off price is more expensive and no quantity discounts that I saw?
    • CommentAuthorrevor
    • CommentTimeJul 3rd 2021
     
    There is an excellent book By Christopher J Pearson " The complete guide to external Wall Insulation" I used it for getting ideas for my own build. Published by Wellgarth Publishing and available here.

    https://www.externalwallinsulation.com/ and for £10 it is an excellent buy.
    • CommentAuthorwookey
    • CommentTimeJul 3rd 2021
     
    <blockquote><cite>Posted By: djh</cite><blockquote><cite>Posted By: RobL</cite>Ewi store have upfront materials price</blockquote>
    On a quick look, the prices don't look very good though? One-off price is more expensive and no quantity discounts that I saw?</blockquote>

    I thought their prices were pretty reasonable. They are cheaper than Backtoearth :-) And provide quite a lot of good info. But with B2E you are paying for plenty of project-specific advice on detailing and materials.

    To answer nbishara, I am not aware of any EWI installlers that will actually do a decent job (i.e extend gables and eaves if needed, insulate past the DPC, move services to avoid thermal bridging etc. I have seen good work on some buildings, but that usually seems to be general builders/contractors. There must be some, and presumably if you are clear what you want plenty of installers will do it right, but you'll have to ask for good detailing not 'whatever is quickest and cheapest', which seems to be what you get unless you make a fuss.

    Youtube is actually quite a good way to check out installers if you have anyone who is posting video in your area. I've seen people doing excellent work there and truly terrible work. One, when I pointed out the things he was doing wrong, wasn't at all interested in advice and then deleted my comment, so you don't want him, but you can't easily tell fromthe comment history.

    Where are you? I can recommend a good renderer near Cambridge. He can almost certainly recommend good insulation installers, but you'll still have to ask for proper detailing, specifically, item by item.
    •  
      CommentAuthornigel
    • CommentTimeJul 3rd 2021
     
    Posted By: djh
    Posted By: RobLEwi store have upfront materials price

    On a quick look, the prices don't look very good though? One-off price is more expensive and no quantity discounts that I saw?


    I bought some from EWI store and got quite large discounts, ring them up and ask them to cost a project up.
    • CommentAuthorSimonD
    • CommentTimeJul 3rd 2021 edited
     
    Posted By: nigel
    Posted By: djh
    Posted By: RobLEwi store have upfront materials price

    On a quick look, the prices don't look very good though? One-off price is more expensive and no quantity discounts that I saw?


    I bought some from EWI store and got quite large discounts, ring them up and ask them to cost a project up.


    I also found them good for relatively small amounts for perimeter and plinth requirements. Once shipping was factored in they beat a local EWI supplier handsdown. They'll also provide non standard thicknesses of EPS with a slightly longer lead time, which was very handy for me.

    Posted By: wookeyThey are cheaper than Backtoearth :-) And provide quite a lot of good info. But with B2E you are paying for plenty of project-specific advice on detailing and materials.


    If you get a response. I contacted B2E several times about my project - never got back to me (and yes, I even spoke to a human being twice who said they'd get another person to call me). :sad:

    From my experience, detailing is absolutely key and I found it challenging to get all the information I needed. I was also misled by one fairly well known supplier in this area.

    I can give a couple of names of people who do know what they're doing and who may also be able to provide names in other regions due to their experience in the field. One of these is based in Oxfordshire, the other in Devon.

    Posted By: revorThere is an excellent book By Christopher J Pearson " The complete guide to external Wall Insulation" I used it for getting ideas for my own build. Published by Wellgarth Publishing and available here.

    https://www.externalwallinsulation.com/" rel="nofollow" >https://www.externalwallinsulation.com/and for £10 it is an excellent buy.


    Thanks for this, looks very interesting and comprehensive. Wish I'd known about this book 6 months ago. I'm still going to get a copy, mind you.
    • CommentAuthorrevor
    • CommentTimeJul 4th 2021
     
    Another idea is if you contact a quality render manufacturing company such as Sto or Alumasc to get a list of their approved contractors around you. A general builder cannot go into a merchant and buy the stuff. They will only sell as I understand to those trained / approved contractors who will also do the EWI. Both these renders highly regarded and certainly I am pleased with the Alumasc on my house.
    • CommentAuthorbhommels
    • CommentTimeJul 4th 2021
     
    For last 25m2 of my EWI project (200mm EPS with brick slip finish), which is on show from the street in front I decided to make my life easy and go for the complete package from Wetherby. So far I have no regrets: it might not be the cheapest option but everything is included and it is quality stuff. Their customer support has been very good too, they supplied a project specification, and answered all my silly questions and provided lots of standard details drawings. They can supply a list of local installers on request - but there are no specific recommendations given, that is up to the customer to sort out apparently.
    • CommentAuthorlineweight
    • CommentTimeJul 8th 2021 edited
     
    Posted By: revorThere is an excellent book By Christopher J Pearson " The complete guide to external Wall Insulation" I used it for getting ideas for my own build. Published by Wellgarth Publishing and available here.

    https://www.externalwallinsulation.com/" rel="nofollow" >https://www.externalwallinsulation.com/and for £10 it is an excellent buy.


    A quick look at the drawings visible on the website suggests it's advocating various things that I thought were considered bad practice - stopping insulation each side of services instead of moving them, window details with cold bridges, etc.
      Screenshot 2021-07-08 at 11.31.40.jpg
    • CommentAuthorrevor
    • CommentTimeJul 8th 2021
     
    I have not seen a better treatise on the subject of EWI. You should not judge a book on its cover in this case an extract on the website. Section 4.2 covers cold bridges with an acceptance of cold bridging as an acceptable risk in some instances, particularly where costly detailing becomes prohibitive. These cold bridging examples are illustrated in the book. As with most things the meaning of anything is in the context.
    • CommentAuthorjms452
    • CommentTimeJul 9th 2021
     
    Posted By: nbisharaI think I'd be better off with reasonably installed standard EWI with cold bridging, than any amount of hypothetical woodfibre, fly past detailing, windows in the EWI


    The best is definitely the energy of the good at times!

    To avoid moving the windows out we moved the insulation in by cutting some of the brickwork around the windows away and filling with foam. This is the triangle in the attached sketch...
      Screenshot 2021-07-09 at 08.56.37.png
    • CommentAuthornbishara
    • CommentTimeJul 10th 2021
     
    <blockquote><cite>Posted By: SimonD</cite>I'm about to go out so just throwing this out there for now. Have you looked at INCA database for EWI installers?<a href="https://www.inca-ltd.org.uk/find-an-inca-member/" rel="nofollow">https://www.inca-ltd.org.uk/find-an-inca-member/</a>

    Might be worth a try and at least you have a better chance of finding someone who knows the detailing requirements of good EWI, even with existing windows still in place<img src="/newforum/extensions/Vanillacons/smilies/standard/smile.gif" alt=":smile:" title=":smile:"></img></blockquote> Thanks! I've been looking on there...still tricky to find domestic scale suppliers from what I can discern.
    • CommentAuthornbishara
    • CommentTimeJul 10th 2021
     
    <blockquote><cite>Posted By: revor</cite>There is an excellent book By Christopher J Pearson " The complete guide to external Wall Insulation" I used it for getting ideas for my own build. Published by Wellgarth Publishing and available here.

    <a href="https://www.externalwallinsulation.com/" rel="nofollow">https://www.externalwallinsulation.com/</a>and for £10 it is an excellent buy.</blockquote>

    Thanks!
    • CommentAuthornbishara
    • CommentTimeJul 10th 2021
     
    <blockquote><cite>Posted By: wookey</cite><blockquote><cite>Posted By: djh</cite><blockquote><cite>Posted By: RobL</cite>Ewi store have upfront materials price</blockquote>
    On a quick look, the prices don't look very good though? One-off price is more expensive and no quantity discounts that I saw?</blockquote>

    I thought their prices were pretty reasonable. They are cheaper than Backtoearth :-) And provide quite a lot of good info. But with B2E you are paying for plenty of project-specific advice on detailing and materials.

    To answer nbishara, I am not aware of any EWI installlers that will actually do a decent job (i.e extend gables and eaves if needed, insulate past the DPC, move services to avoid thermal bridging etc. I have seen good work on some buildings, but that usually seems to be general builders/contractors. There must be some, and presumably if you are clear what you want plenty of installers will do it right, but you'll have to ask for good detailing not 'whatever is quickest and cheapest', which seems to be what you get unless you make a fuss.

    Youtube is actually quite a good way to check out installers if you have anyone who is posting video in your area. I've seen people doing excellent work there and truly terrible work. One, when I pointed out the things he was doing wrong, wasn't at all interested in advice and then deleted my comment, so you don't want him, but you can't easily tell fromthe comment history.

    Where are you? I can recommend a good renderer near Cambridge. He can almost certainly recommend good insulation installers, but you'll still have to ask for proper detailing, specifically, item by item.</blockquote>

    Thanks - I hadn't thought of youtube actually. I'm not a million miles from Cambridge - Buckinghamshire so yes please, recommendation would be very helpful - and thanks for the rest of the advice :-)
    • CommentAuthornbishara
    • CommentTimeJul 10th 2021
     
    <blockquote><cite>Posted By: SimonD</cite><blockquote><cite>Posted By: nigel</cite><blockquote><cite>Posted By: djh</cite><blockquote><cite>Posted By: RobL</cite>Ewi store have upfront materials price</blockquote>
    On a quick look, the prices don't look very good though? One-off price is more expensive and no quantity discounts that I saw?</blockquote>

    I bought some from EWI store and got quite large discounts, ring them up and ask them to cost a project up.</blockquote>

    I also found them good for relatively small amounts for perimeter and plinth requirements. Once shipping was factored in they beat a local EWI supplier handsdown. They'll also provide non standard thicknesses of EPS with a slightly longer lead time, which was very handy for me.

    <blockquote><cite>Posted By: wookey</cite>They are cheaper than Backtoearth :-) And provide quite a lot of good info. But with B2E you are paying for plenty of project-specific advice on detailing and materials.
    </blockquote>

    If you get a response. I contacted B2E several times about my project - never got back to me (and yes, I even spoke to a human being twice who said they'd get another person to call me).<img src="/newforum/extensions/Vanillacons/smilies/standard/sad.gif" alt=":sad:" title=":sad:"></img>

    From my experience, detailing is absolutely key and I found it challenging to get all the information I needed. I was also misled by one fairly well known supplier in this area.

    I can give a couple of names of people who do know what they're doing and who may also be able to provide names in other regions due to their experience in the field. One of these is based in Oxfordshire, the other in Devon.

    <blockquote><cite>Posted By: revor</cite>There is an excellent book By Christopher J Pearson " The complete guide to external Wall Insulation" I used it for getting ideas for my own build. Published by Wellgarth Publishing and available here.

    <a href="<a href=" rel="nofollow">https://www.externalwallinsulation.com/</a>" rel="nofollow" >https://www.externalwallinsulation.com/and for £10 it is an excellent buy.</blockquote>

    Thanks for this, looks very interesting and comprehensive. Wish I'd known about this book 6 months ago. I'm still going to get a copy, mind you.</blockquote>

    Thanks very much - I'd love a recommendation for someone Oxford way because that's not that far from me :-)

    Tania
    • CommentAuthornbishara
    • CommentTimeJul 10th 2021
     
    <blockquote><cite>Posted By: jms452</cite><blockquote><cite>Posted By: nbishara</cite>I think I'd be better off with reasonably installed standard EWI with cold bridging, than any amount of hypothetical woodfibre, fly past detailing, windows in the EWI</blockquote>

    The best is definitely the energy of the good at times!

    To avoid moving the windows out we moved the insulation in by cutting some of the brickwork around the windows away and filling with foam. This is the triangle in the attached sketch...<div class="Attachments" id="Attachments_290481"><ul><div><img src="/newforum/extensions/InlineImages/image.php?AttachmentID=7962" alt="Screenshot 2021-07-09 at 08.56.37.png"></img></div></ul></div></blockquote>

    thanks - that's really interesting re your windows..and you are spot on about the best being the enemy of the good...i just need to do *something*...but obviously not something like the nightmare EWI fails I've seen in some presentations...but maybe not my ideal something either !
    • CommentAuthorjms452
    • CommentTimeJul 11th 2021
     
    Posted By: nbisharaI am not aware of any EWI installlers that will actually do a decent job (i.e extend gables and eaves if needed, insulate past the DPC, move services to avoid thermal bridging etc


    The only way we got a half decent job was by:
    Reading the EWI handbook & lurking on GBF
    Drawing out what we wanted
    Getting input from EWI installer on what they would/wouldn't do (and a detailed quote).
    Getting a decent builder to do all the prep (gable extension, services, above picture etc)
    Making sure the EWI installer did what they said they'd do (which was actually a bit painful as the sales guy had disappeared by then so the detailed quote was invaluable).
    Going round at the end with silicone joining the render to everything else

    Basically moderate your expectations here - Most EWI installers seem to be plasters who did an extra course. They'll do a nice job of the rendering and everything else is secondary.

    this was ten years ago - maybe things are a bit more joined up now...
  20.  
    jms452 wrote:

    ''this was ten years ago - maybe things are a bit more joined up now...''

    I think you will find they are not. I have *never* found an EWI installer who will take on the 'enabling works' too (which is really what a householder client wants, IMO). I have also never found one whose views on gaps (**There should not be any***) between insulation sheets and on thermal bridges are exactly the same as mine.
  21.  
    Posted By: jms452Basically moderate your expectations here - Most EWI installers seem to be plasters who did an extra course. They'll do a nice job of the rendering and everything else is secondary.

    That is the problem I have found with all builders both here and in the UK - make sure the top coat that shows looks good and never mind what is underneath seems to be the way they all work.
    • CommentAuthorrevor
    • CommentTimeJul 11th 2021
     
    When I was considering EWI for the stone part of our house I had a look at the work of a potential installer. It was a damp day and I could see the joints between the insulation boards as dark lines. In the end I decided to do the EWI myself and rather than have it rendered decided to create a cavity between it and the cedar cladding that I covered it with. On the block built extension that was rendered with Alumasc system and the contractor brought in for the main part of the work Romanian and Hungarian renderers. They were very skilled I was most impressed with how they worked. I wonder following Brexit if they are around anymore, shame if they are not.
  23.  
    <blockquote><cite>Posted By: revor</cite>decided to create a cavity between it and the cedar cladding</blockquote>

    Do you have any diagrams or pictures of this ? I'd be interested to see if so please.
    • CommentAuthorrevor
    • CommentTimeJul 13th 2021
     
    Here is a link to the approach I used. It shows the various options with this board I had to do some prework to the wall as it is stone.

    https://www.barbourproductsearch.info/Kingspan%20Kooltherm%20K5%20External%20Wall%20Board%208th%20Issue%20b%20March%202011-file056213.pdf

    I used K5 boards 50 mm in 2 staggered layers. I had a very uneven stone wall so battened it out with approx. 70 mm thick treated timbers with packers vertical to start, fixing with stainless screws to the stone, As I could see the stone I could aim for a good fix point I had previously hacked off the old cement based pebble dash.
    Between the battens I lime rendered screeding down to a level between the battens so left with 50 mm depth to take the first layer of boards. I then cross battened with 50 mm thick timbers at the board width and inserted the next layer. Covered it with breathable membrane and fastened 35x 45mm battens vertical from top to bottom at 600 mm centres through the insulation into the first layer timber, and fastened the cladding to it.
    I do have photos but can't access them as computer crashed some 3 years ago and whilst they are there I cannot access them.
    It was a lengthy process made difficult because the stone wall was so uneven and had a twist in it. I prepared the timbers from bigger stock to get the thicknesses I needed all fixings were stainless 6mm in a range of sizes. The cladding nails were A4 grade. Job was also complicated by accommodating a veranda on the front and lean to conservatory roof on the side but they served as convenient mid base rails. Used 10 x 2 treated timber wall plates fastened to the stone using s/s thread rod in epoxy resin.

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