EWI renders ? experiences & recommendations? suppliers?

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mas

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Hi Guys (and Ladies),

I'm after recommendations and feedback on render systems for EWI.

I've had many differing stories from builders so I thought I'd come and ask the people who actually do the thing.

I'm putting EWI on our house and will be using a combination of EPS and kingspan (for the bit adjacent to the boundary). So far as I can tell, the general recommendation is for a base layer with mesh, then a top coat. I've seen people recommend a one coat system but.....

What I'm particularly interested in is adhesion to EPS/PIR/PUR (esp foil faced like celotex/kingspan) and ease of use for a reasonable DIY'er.

Recommendations for suppliers (I'd prefer ready mixed, just for convenience) who will do small quantities?

Also comments on how robust the systems are. I've seen some EWI where the render coat is clearly not strong enough and the surface is easily damaged. Don't know if that is down to using a system designed for one of the rigid thermal boards (pavatex or similar) on the wrong insulation (eps).

And if anyone knows a supplier of mechanical fixings suitable for 200mm insulation...

If you've got to the end of this, then thanks for reading!

cheers

Mark
 
Hi Mas,

We supply JUB thin-coat Render, we would be happy to discuss the product with you if you want to give us a call. Numbers are below.

Ryan
 
Hi Guys (and Ladies),

I'm after recommendations and feedback on render systems for EWI.

I've had many differing stories from builders so I thought I'd come and ask the people who actually do the thing.

I'm putting EWI on our house and will be using a combination of EPS and kingspan (for the bit adjacent to the boundary). So far as I can tell, the general recommendation is for a base layer with mesh, then a top coat. I've seen people recommend a one coat system but.....

What I'm particularly interested in is adhesion to EPS/PIR/PUR (esp foil faced like celotex/kingspan) and ease of use for a reasonable DIY'er.

Recommendations for suppliers (I'd prefer ready mixed, just for convenience) who will do small quantities?

Also comments on how robust the systems are. I've seen some EWI where the render coat is clearly not strong enough and the surface is easily damaged. Don't know if that is down to using a system designed for one of the rigid thermal boards (pavatex or similar) on the wrong insulation (eps).

And if anyone knows a supplier of mechanical fixings suitable for 200mm insulation...

If you've got to the end of this, then thanks for reading!

cheers

Mark

diyer? dont say your going to tackle a job of this nature yourself?
 
Why not?

I've slaked my own lime, made my own lime putty, plaster and limewash. Replaced joists and floors, rewired houses, repaired roofs, fitted MHRV etc.

Done plenty of researchon the concepts, interstitial condensation, failure modes as reported in europe and north america.
 
Thanks Guys!

That's *really* helpful. :rolleyes:

I hoped to get comparative info on the products from weber/sto/jub/wetherby/marmorite/parex/etc.

Can anyone suggest a forum where I might get such info?
 
do a search on there web sites then.

I know renderers whove been in the game for years that cant complete ewi systems to a good standard, through lack of experience and knowlege so your stance that your going to 'tackle' it has creased me.
 
they all do theory and a bit of practical courses, but you need to be a compitant renderer before you start.
 
Go on said company's websites the info is there you can use an armour mesh doubled up to increase impact resistance and some of the basecoats are more robust than others don't know about adhesion onto a foil faced board though cannot see it working there is a system by structherm which has a metal mesh on the eps panels which is pugged out with sand and cement before applying the basecoat think its belgian
 
Hi Mas

I respect the fact that you want to have a go on your own house..... I sell a render board and am not a spread - I am more than capable of puting render onto a board for a demo or sample and make a resonable job of it..... but a large area takes a lot of skill to make it look "average" let alone in a state that I would want to live in the property.

There is a reason that most EWI render system suppliers only warrant projects done by approved contractors - these guys know what to do!

Fixing the insulation ready for renedring looks easy, but do it wrong and get a failure and the whole house needs putting right (patches are hard rework - if not impossible in some cases!).

Rendering a small flat area with no windows, corners, base or head details and all the other little details needed - could probably be done...... but you will have to live in it and maybe want to sell it later!

Do yourself a favour - get a pro in and offer to help - if that is what you want to do (agree it before you appoint them!)

Good Luck mate
 
if i was you i would go on a coarse ,i know weber do them ,best of luck
I went on a knauf course it was pointless I was the only plastrer there and I was promised I'd cards and all kinds of info they won't answer any of my emails now they had my money that's all they care about
 
Hi Mas

I respect the fact that you want to have a go on your own house..... I sell a render board and am not a spread - I am more than capable of puting render onto a board for a demo or sample and make a resonable job of it..... but a large area takes a lot of skill to make it look "average" let alone in a state that I would want to live in the property.

There is a reason that most EWI render system suppliers only warrant projects done by approved contractors - these guys know what to do!

Fixing the insulation ready for renedring looks easy, but do it wrong and get a failure and the whole house needs putting right (patches are hard rework - if not impossible in some cases!).

Rendering a small flat area with no windows, corners, base or head details and all the other little details needed - could probably be done...... but you will have to live in it and maybe want to sell it later!

Do yourself a favour - get a pro in and offer to help - if that is what you want to do (agree it before you appoint them!)

Good Luck mate

well explained.
 
Big Steve - That is not good!!

Call me and let me know the details! (I'll do some digging for you...)

Richard Lord - details on my profile...
 
I went on a knauf course it was pointless I was the only plastrer there and I was promised I'd cards and all kinds of info they won't answer any of my emails now they had my money that's all they care about


Hi Steve,

We have Knauf here today doing training. I spoke with Kevin about your card and he assures me it's on the way. It is quite a long process and waiting time. You are still approved so if you need to order any materials let me know, all I need are your details, i.e company name, your name, and I can pass it through that way.

Ryan
 
Appreciate the more helpful comments.

I can apply lime render and sand/cement render to a reasonable standard - better than whoever did the adjacent properties anyway. My internal plastering is also decent (except ceilings). Due to the shape of the property I have a flat wall 1.5mx5m to use as my testing ground.
I'm not averse to going on courses, but the course details I've seen look unimpressive.

The application details shown on youtube etc tend to be simplistic - I suppose that it is reasonable in a new build scenario to assume that walls will be straight and flat, but that doesn't apply to retrofit. I think the commonly used idea of expanding foam at the joints of the insulation panels seems sensible - butt jointing has significant limitations on non-planar substrates. Also I quite like the idea of multiple layers of insulation rather than single layers as reducing cold bridging at joints and being easier to get a smoother fit on irregular walls (try getting even 100mm thick insulation board to flex.)

As water penetration is cited as the main failure mode, overlapped layers should also help in that respect - although the key is obviously at the detailing in door/window reveals and at the roof/eaves junction. It would also mean that I could embed something within the wall to provide a fixing for downpipes etc. What do you usually do about external fixings on thick ewi?

I've not found any info from the suppliers about extending insulation below ground level. I know that this is beneficial from an insulation point of view (sap calcs) but have conflicting info on how to detail this and indeed what insulation is suitable. I've done a trial patch with a french drain and eps to see if that causes problems, but after a year there is no sign of damp.


Any helpful comments still welcome. TBH looking at this forum I would have thought that a thread going over practical experiences with the ewi systems would be useful to many people here.
 
MAS

Dont use foil backed phenolic. there are different grades for differnt things, same with eps - you cant use the 8x4 cheap stuff from travis perkins - its not for rendering onto.
 
I and some others on here suffer from verbal diarrhoea going into depth about processes of how to do things. For some reason i dont want to share anything with you mas.
I suppose this forum is like any other......if it was a car tuning forum and you asked 'I've changed the odd spark plug, topped up the coolants, fitted new alloys in my time but not so great at changing exhausts....I'd like some tips as I'm gonna drop a bigger engine in my car myself'. 'If you all could take the time to explain in detail how exactly to do it that'd be great'. Then when someone wisely says 'better off taking it to a garage mate' you get all defensive as if its everyone's job here to share they're knowledge, tricks & secrets gained through experience both up and down over time with you.

Can't you see that there's a big difference between watching something be done and practically doing it. This is a plastering forum where mostly plasterers talk to other plasterers about plastering stuff. Yes, there are lots of beginners and inexperienced people who come on asking how best to go about doing this and that. Most relish sharing some knowledge and guidance with keen folk who knock themselves back and are eager to learn.

Unfortunately, you do get jumped up m***** f****** with no experience armed with a load of reading & vids basically saying 'can someone nurse me through the whole process of how to do this & that but I'm so amazing that i don't care if it took you 5 yrs to master that, I'll do it overnight'. Arrogant, antagonistic and above all just plain disrespectful.
Good luck. Then again, I don't suppose you'll need any as it'll be a masterpiece. I mean how hard can it be......
 
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Ill be the first to admit that ive never done EWI, but Im a compitent plasterer/renderer and theres not a cat in hells chance I would tackle this sort of work without hands on experience over a period of time.
 
ive rectified various ewi systems of late, that have been fit to a poor standard. As with any render application there is no black art to it,just know how and experience, that you will not learn on a course.
If your going to come on here ask for general information on systems and how they fitted from a customers view in order to choose the best system for your build for a contractor to undertake, then fair play, but if your fishing for advice to carry out the job yourself for what in essance is a skilled job then you are going to be met with negative comments, which is what youve generally got.
 
I and some others on here suffer from verbal diarrhoea going into depth about processes of how to do things. For some reason i dont want to share anything with you mas.
I suppose this forum is like any other......if it was a car tuning forum and you asked 'I've changed the odd spark plug, topped up the coolants, fitted new alloys in my time but not so great at changing exhausts....I'd like some tips as I'm gonna drop a bigger engine in my car myself'. 'If you all could take the time to explain in detail how exactly to do it that'd be great'. Then when someone wisely says 'better off taking it to a garage mate' you get all defensive as if its everyone's job here to share they're knowledge, tricks & secrets gained through experience both up and down over time with you.

Can't you see that there's a big difference between watching something be done and practically doing it. This is a plastering forum where mostly plasterers talk to other plasterers about plastering stuff. Yes, there are lots of beginners and inexperienced people who come on asking how best to go about doing this and that. Most relish sharing some knowledge and guidance with keen folk who knock themselves back and are eager to learn.

Unfortunately, you do get jumped up m***** f****** with no experience armed with a load of reading & vids basically saying 'can someone nurse me through the whole process of how to do this & that but I'm so amazing that i don't care if it took you 5 yrs to master that, I'll do it overnight'. Arrogant, antagonistic and above all just plain disrespectful.
Good luck. Then again, I don't suppose you'll need any as it'll be a masterpiece. I mean how hard can it be......
Very well put Goody ,we all try to help out as much as we can on here ,but sometimes, just have to be as honest, as you have just been
 
I and some others on here suffer from verbal diarrhoea going into depth about processes of how to do things. For some reason i dont want to share anything with you mas.
I suppose this forum is like any other......if it was a car tuning forum and you asked 'I've changed the odd spark plug, topped up the coolants, fitted new alloys in my time but not so great at changing exhausts....I'd like some tips as I'm gonna drop a bigger engine in my car myself'. 'If you all could take the time to explain in detail how exactly to do it that'd be great'. Then when someone wisely says 'better off taking it to a garage mate' you get all defensive as if its everyone's job here to share they're knowledge, tricks & secrets gained through experience both up and down over time with you.

I guess that in that scenario, rather than just suck my teeth and say 'Oh, you can't do that!', I'd give some sort of reasoning why.
Explain that it isn't just about the physical drop in of the engine and matching up the mounts, but that you'd also need to sort out the interaction with the ECU and sensors; ensure adequate fuel and air flow; possibly need a bespoke bellhousing; cooling; driveshaft/gearbox torque limits; the need for matching brake and suspension upgrades; the legal issues with DVLA and insurance; cost of necessary tools; etc, etc. and I'd suggest places that the OP could go to get more info.

In essence, show them why it might not be a good idea to pile in, because they probably don't appreciate the complexity of the task they are contemplating.

For what its worth, in my area of expertise I regularly give free detailed advice and point people to resources and competing suppliers. I take the approach I've detailed above - give an indication of what the issues are - rather than be dismissive or abusive.

Can't you see that there's a big difference between watching something be done and practically doing it. This is a plastering forum where mostly plasterers talk to other plasterers about plastering stuff. Yes, there are lots of beginners and inexperienced people who come on asking how best to go about doing this and that. Most relish sharing some knowledge and guidance with keen folk who knock themselves back and are eager to learn.

Of course. I fully appreciate that most trades depend on experience and most importantly skill. That applies for things from plastering to dentistry.


Unfortunately, you do get jumped up m***** f****** with no experience armed with a load of reading & vids basically saying 'can someone nurse me through the whole process of how to do this & that but I'm so amazing that i don't care if it took you 5 yrs to master that, I'll do it overnight'. Arrogant, antagonistic and above all just plain disrespectful.
Good luck. Then again, I don't suppose you'll need any as it'll be a masterpiece. I mean how hard can it be......

I do know that some EWI installs are terrible and fail quickly. As a non-expert, I don't (yet) have the knowledge to evaluate the systems and their drawbacks. Like going to a dentist, I have no idea how good they are or the benefits of say different crown systems.

I like to have an understanding of something rather then just buy on price. If it *is* so difficult then why is that? Europeans have been slapping EWI up for years, and I've spoken to a german installer who tells me that it isn't difficult or particularly complex beyond detailing.

So I asked what I thought would be a fairly uncontroversial question about the systems - I know that manufacturers will not go through the issues with their systems on their web sites, lots of skills come down to knowing where things don't work and how to get round that.

This is a plastering forum, but there seem to be few topics on EWI. EWI should be a growing sector for retrofit as well as new build and the experience of those who have used different systems is valuable to other experts as well as members of the general public.

I've been surprised that the initial responses were dismissive and unhelpful, so I went on to say that I can actually plaster and render to a reasonable standard and I do have some experience, allbeit that I'm no pro - thinking that we could move on from the teeth sucking and maybe get some useful info on the render systems.
There is a lack of info in the UK and much contradictory info. eg I've seen foil backed boards used as EWI and rendered onto - don't know the system used, but it is done, maybe it will all fall off next winter, maybe not. I've had one installer swear that EPS should never be used, while others recommend it. Frankly, I'm rapidly coming to the conclusion that a lot of installers don't actually understand what they're doing - they just do what they've been shown. I'm sure that there are many different ways to achieve the end result, and different people will have their own preferences wrt techniques and materials, but I would like to understand the reasoning behind those choices.

In general I've always found that the people who are most secretive & defensive of their 'knowledge, tricks & secrets' are those where things are not actually very difficult or where people don't actually have an understanding of why they do things the way that they do.




Thanks to those who were helpful. :RpS_thumbup:
 
I guess that in that scenario, rather than just suck my teeth and say 'Oh, you can't do that!', I'd give some sort of reasoning why.
Explain that it isn't just about the physical drop in of the engine and matching up the mounts, but that you'd also need to sort out the interaction with the ECU and sensors; ensure adequate fuel and air flow; possibly need a bespoke bellhousing; cooling; driveshaft/gearbox torque limits; the need for matching brake and suspension upgrades; the legal issues with DVLA and insurance; cost of necessary tools; etc, etc. and I'd suggest places that the OP could go to get more info.

In essence, show them why it might not be a good idea to pile in, because they probably don't appreciate the complexity of the task they are contemplating.

For what its worth, in my area of expertise I regularly give free detailed advice and point people to resources and competing suppliers. I take the approach I've detailed above - give an indication of what the issues are - rather than be dismissive or abusive.



Of course. I fully appreciate that most trades depend on experience and most importantly skill. That applies for things from plastering to dentistry.




I do know that some EWI installs are terrible and fail quickly. As a non-expert, I don't (yet) have the knowledge to evaluate the systems and their drawbacks. Like going to a dentist, I have no idea how good they are or the benefits of say different crown systems.

I like to have an understanding of something rather then just buy on price. If it *is* so difficult then why is that? Europeans have been slapping EWI up for years, and I've spoken to a german installer who tells me that it isn't difficult or particularly complex beyond detailing.

So I asked what I thought would be a fairly uncontroversial question about the systems - I know that manufacturers will not go through the issues with their systems on their web sites, lots of skills come down to knowing where things don't work and how to get round that.

This is a plastering forum, but there seem to be few topics on EWI. EWI should be a growing sector for retrofit as well as new build and the experience of those who have used different systems is valuable to other experts as well as members of the general public.

I've been surprised that the initial responses were dismissive and unhelpful, so I went on to say that I can actually plaster and render to a reasonable standard and I do have some experience, allbeit that I'm no pro - thinking that we could move on from the teeth sucking and maybe get some useful info on the render systems.
There is a lack of info in the UK and much contradictory info. eg I've seen foil backed boards used as EWI and rendered onto - don't know the system used, but it is done, maybe it will all fall off next winter, maybe not. I've had one installer swear that EPS should never be used, while others recommend it. Frankly, I'm rapidly coming to the conclusion that a lot of installers don't actually understand what they're doing - they just do what they've been shown. I'm sure that there are many different ways to achieve the end result, and different people will have their own preferences wrt techniques and materials, but I would like to understand the reasoning behind those choices.

In general I've always found that the people who are most secretive & defensive of their 'knowledge, tricks & secrets' are those where things are not actually very difficult or where people don't actually have an understanding of why they do things the way that they do.




Thanks to those who were helpful. :RpS_thumbup:
hed give you a run for your money any day goody it would be amazing to see mad and goody having a chat over a beer it would a proper i will get me coat scenario
 
I guess that in that scenario, rather than just suck my teeth and say 'Oh, you can't do that!', I'd give some sort of reasoning why.
Explain that it isn't just about the physical drop in of the engine and matching up the mounts, but that you'd also need to sort out the interaction with the ECU and sensors; ensure adequate fuel and air flow; possibly need a bespoke bellhousing; cooling; driveshaft/gearbox torque limits; the need for matching brake and suspension upgrades; the legal issues with DVLA and insurance; cost of necessary tools; etc, etc. and I'd suggest places that the OP could go to get more info.

In essence, show them why it might not be a good idea to pile in, because they probably don't appreciate the complexity of the task they are contemplating.

For what its worth, in my area of expertise I regularly give free detailed advice and point people to resources and competing suppliers. I take the approach I've detailed above - give an indication of what the issues are - rather than be dismissive or abusive.



Of course. I fully appreciate that most trades depend on experience and most importantly skill. That applies for things from plastering to dentistry.




I do know that some EWI installs are terrible and fail quickly. As a non-expert, I don't (yet) have the knowledge to evaluate the systems and their drawbacks. Like going to a dentist, I have no idea how good they are or the benefits of say different crown systems.

I like to have an understanding of something rather then just buy on price. If it *is* so difficult then why is that? Europeans have been slapping EWI up for years, and I've spoken to a german installer who tells me that it isn't difficult or particularly complex beyond detailing.

So I asked what I thought would be a fairly uncontroversial question about the systems - I know that manufacturers will not go through the issues with their systems on their web sites, lots of skills come down to knowing where things don't work and how to get round that.

This is a plastering forum, but there seem to be few topics on EWI. EWI should be a growing sector for retrofit as well as new build and the experience of those who have used different systems is valuable to other experts as well as members of the general public.

I've been surprised that the initial responses were dismissive and unhelpful, so I went on to say that I can actually plaster and render to a reasonable standard and I do have some experience, allbeit that I'm no pro - thinking that we could move on from the teeth sucking and maybe get some useful info on the render systems.
There is a lack of info in the UK and much contradictory info. eg I've seen foil backed boards used as EWI and rendered onto - don't know the system used, but it is done, maybe it will all fall off next winter, maybe not. I've had one installer swear that EPS should never be used, while others recommend it. Frankly, I'm rapidly coming to the conclusion that a lot of installers don't actually understand what they're doing - they just do what they've been shown. I'm sure that there are many different ways to achieve the end result, and different people will have their own preferences wrt techniques and materials, but I would like to understand the reasoning behind those choices.

In general I've always found that the people who are most secretive & defensive of their 'knowledge, tricks & secrets' are those where things are not actually very difficult or where people don't actually have an understanding of why they do things the way that they do.




Thanks to those who were helpful. :RpS_thumbup:

yep I know nowt and have no understanding of the subject.
 
ive rectified various ewi systems of late, that have been fit to a poor standard. As with any render application there is no black art to it,just know how and experience, that you will not learn on a course.
If your going to come on here ask for general information on systems and how they fitted from a customers view in order to choose the best system for your build for a contractor to undertake, then fair play, but if your fishing for advice to carry out the job yourself for what in essance is a skilled job then you are going to be met with negative comments, which is what youve generally got.

We do a fair bit of EWI refurb and remedial work due to poorly installed and failing systems. plent of it to come too with all the new to the industry companies just set up for GreenD

Was parked next to St Helens college today that must be all of 2 years old at the most - horizontal cracking appearing now. and a Mono house round the corner from me looks a mess - gable split with a bead and done on two different days with different backings and it looks two totally different colours. its a right mess. people pay for firms to install who dont really know fuilly how to do it but thats the uk over i suppose

Best advise i can give mas is get a good lad on board for a few days if he is hell bent on doing it himself, then he can ask all the questions he likes in person
 
its all very technical isnt it. slap it up mas and get someone with experience to help finish it. 200mm with foil though? might aswell block up the windows and go the whole hog. oh and get a gun.....

ps candles!!! i forgot the candles!
 
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