ProDave Posted February 9, 2021 Share Posted February 9, 2021 Early on in our build in summer 2016, the outside of the house was rendered using the Baumit.com render system consisting of a lime based base coat mixed from powder called MC55W, a fibreglass mesh was rolled into this while wet. Then it was painted with DG27 primer and a top coat of Silikon Top applied. This was all applied to Pavatex wood fibre board cladding a timber framed house. There was a BBA certificate for this render system that I have attached. The result was crisp and sharp looking. But that did not last long. First winter, 2017 the first problem appeared, the top coat started blistering along the bottom of the east facing garage wall. It occurred while we were away over a cold spell, so thought perhaps it was a build up of snow along the bottom of the garage wall? (we came back to very thick solid ice all over the driveway). The plasterer came and re worked that using materials we still had left over. But since then the problem has spread. Next year it showed itself as just a couple of blisters on the East wall. But it has continued to get worse. After another year or 2 the blisters started to spread and the early ones started to crack. It is now in places on 3 walls, (none yet on the south facing wall) and along the top of one door and one window it has come away from the drip bead and is cracking all along the top. I have been trying via the plasterer for some time to get a resolution. He kept saying he was trying to contact the rep for the area to get him to come and look but with no luck, and of course all last year Covid has been the excuse. So while I don't have much else to do just now I have picked this up and tried contacting the supplier myself. First thing I find is the company that supplied it merged with another so are now trading under a different name, and the rep we were trying to contact no longer works for them. I have been given the details of a person that will deal with this so I have sent an email to start the discussion and hope we can find a resolution. In the mean time here are some photographs. This is the East wall, the garage wall. All allong the bottom it has delaminated from the drip bead, and all the way up there are blisters though they can be hard to see. Note the corner joint by the door is delaminating. Above the garage door on the east wall, delaminatinf all around the door and some hard to see blisters further up. Some of the east wall blisters close up, one has started to crack. Corner of garage east wall and north wall delaminating at the corner West facing wall, hard to see blisters in the wall and corner delaminating West wall above kitchen window delaminating and cracking And saving the worst until last, north wall corner of garage. This winter a chunk of the base coat fell off. I don't believe the root of the problem is related to the base coat, rather this is what happens with the top coat failed allowing water to soak into the base coat then the action of frost has cracked it. While I await a response from the supplier, I wonder if anyone has seen anything similar with a thin coat render system, if so what was the reason for the problem and what was the resolution? bba-certificate-for-nbt-timber-frame-rendered.pdf 1 Link to comment Share on other sites More sharing options...
ToughButterCup Posted February 9, 2021 Share Posted February 9, 2021 @nod will be along in a minute..... Link to comment Share on other sites More sharing options...
Mr Punter Posted February 9, 2021 Share Posted February 9, 2021 2 minutes ago, ToughButterCup said: @nod will be along in a minute..... A bit cold for him to start today. 2 Link to comment Share on other sites More sharing options...
nod Posted February 9, 2021 Share Posted February 9, 2021 Whatever the reason for render delaminating It all needs to be replaced and it’s up to the render company to come up with a solution The render company should get a rep out ASAP Have walk through and go through what they used and how it was applied Dig out the invoice for the materials Then send samples of the base and top coat off to the lab The supplier May stand all of the work Or May just stump up for the material and Scaffolding These things do happen Which why through coloured render prices are high Looking at the pictures Dave It’s past the point of patching up Link to comment Share on other sites More sharing options...
Jason L Posted February 9, 2021 Share Posted February 9, 2021 Is the orange mesh in the top coat, that looks like it barely has any cover on it ? Link to comment Share on other sites More sharing options...
ProDave Posted February 9, 2021 Author Share Posted February 9, 2021 21 minutes ago, nod said: Whatever the reason for render delaminating It all needs to be replaced and it’s up to the render company to come up with a solution The render company should get a rep out ASAP Have walk through and go through what they used and how it was applied Except the designer of the house specified the system and provided the BBA certificate, I bought the materials, and a plasterer applied it. It was not a contract job to a "render company" The plasterer has offered to rework for free (though that will be tested if the whole lot has to come off) and I am awaiting a response from the supplier. Link to comment Share on other sites More sharing options...
ProDave Posted February 9, 2021 Author Share Posted February 9, 2021 5 minutes ago, Jason L said: Is the orange mesh in the top coat, that looks like it barely has any cover on it ? No that is the mesh embeded in the base coat. I don't think failure of the base coat is the root cause, rather because that section of top coat did not get repaired, water has soaked into the base coat in that region and frost has cracked it. I have not started to peel back any of the delaminated sections to look, I am awaiting communication from the supplier before I do that. Link to comment Share on other sites More sharing options...
SimonD Posted February 9, 2021 Share Posted February 9, 2021 Here is a link to a paper that looks at ETICS failure and common reasons. Has some good photos similar to your situation. https://www.apfac.pt/congresso2012/comunicacoes/Paper 104_2012.pdf Good luck dealing with NBT or Soprema as they are now. I had a nightmare even dealing with their sales people so completely change materials and suppliers for my house. However, on a hopefully positive note, my experience with their technical people was very good. Have you contacted Baumit directly as this may be more in their domain than NBT? The EWI looks very low to the ground. Maybe it's the photos but was it installed > 30cm above ground level? Link to comment Share on other sites More sharing options...
nod Posted February 9, 2021 Share Posted February 9, 2021 1 hour ago, ProDave said: Except the designer of the house specified the system and provided the BBA certificate, I bought the materials, and a plasterer applied it. It was not a contract job to a "render company" The plasterer has offered to rework for free (though that will be tested if the whole lot has to come off) and I am awaiting a response from the supplier. As I’ve said These things do happen It won’t be the first one the rep has been out to Or the last The rep should be pretty keen to sort it out I did four pairs of large house (200m2 each) Like a grey bloom appeared we washed off and it came back Supplier just said it’s a natural product Supplied a mild acid and The pay for two men for a week and I hired a skyjack and jet washer All sorted The builder decided to hold payment for six months just in case Still haven’t a clue what caused this The rep was only there 30 minutes Link to comment Share on other sites More sharing options...
Big Jimbo Posted February 9, 2021 Share Posted February 9, 2021 Bloody hell Pro Dave. Gutted for you. That looks like one large problem that you just don't need. Somebody else had a problem with the render boards pillowing. Hope you get it sorted without it costing you. Link to comment Share on other sites More sharing options...
ProDave Posted February 9, 2021 Author Share Posted February 9, 2021 24 minutes ago, SimonD said: Here is a link to a paper that looks at ETICS failure and common reasons. Has some good photos similar to your situation. https://www.apfac.pt/congresso2012/comunicacoes/Paper 104_2012.pdf Good luck dealing with NBT or Soprema as they are now. I had a nightmare even dealing with their sales people so completely change materials and suppliers for my house. However, on a hopefully positive note, my experience with their technical people was very good. Have you contacted Baumit directly as this may be more in their domain than NBT? The EWI looks very low to the ground. Maybe it's the photos but was it installed > 30cm above ground level? Thanks, excellent link. A snippet from that Exfoliationis apartial detachmentof thethinsurface layersthatdeformwithout detaching completelyfromthesubstrate. Exfoliation can occur in limited areas, such as along insulation board joint (Figure 3b),or be more extensive and involve the entire surface. The main cause is the façade exposure to dimensional changes due to external stress. These result in dilatationand contraction, determining tangential stresses, because of different coefficients of thermal expansion of materials and also by the water absorption of the coveringthat decreases the adhesion of the mortar to the insulation board. This failure may be caused by incompatibilities or errors in installation, probably because of a low dose of binder, a wrong water-cement ratio, or bad weather conditions during application.This mechanismallowsfurtherwater infiltration into thesubstrate, up to thetotal detachmentof the coating. That fits what I am experienceing but there is no way I can see there is any case of "dimensional changes" and no issue with incompatibility or poor weather during application. Yes the EWI is low to the ground just on that garage wall. If that was the only area of concern then I could believe that was the caiuse, but that would not explain why it is occuring above doors and windows and in other places where the EWI finishes much higher above the ground. Link to comment Share on other sites More sharing options...
ADLIan Posted February 9, 2021 Share Posted February 9, 2021 The BBA certificate referenced above is no longer valid. Looks to have been withdrawn in Feb 2016. Link to comment Share on other sites More sharing options...
ProDave Posted February 9, 2021 Author Share Posted February 9, 2021 5 minutes ago, Big Jimbo said: Bloody hell Pro Dave. Gutted for you. That looks like one large problem that you just don't need. Somebody else had a problem with the render boards pillowing. Hope you get it sorted without it costing you. The issue is one of trust. Even when "fixed" will i trust it not to happen again in 5 or 10 years? Yes gutted does not come close. this has been brewing up for a while and I have pushed it back relying on the plasterer saying he will sort it for a while as I could not do with the distraction while still busy building, but now is the time to face it and shout until I get a resolution. Link to comment Share on other sites More sharing options...
ProDave Posted February 9, 2021 Author Share Posted February 9, 2021 1 minute ago, ADLIan said: The BBA certificate referenced above is no longer valid. Looks to have been withdrawn in Feb 2016. Yes I believe that is so. That does not bode well. What is one supposed to do when you chose and installed a system in good faith knowing it had a BBA certificate only to find it no longer has. It is worryingly beginning to sound like "not fit for purpose" which opens a whole new can of worms. Link to comment Share on other sites More sharing options...
Thedreamer Posted February 9, 2021 Share Posted February 9, 2021 Gutted for you. I hope you get this resolved. Can you claim on a self build insurance policy for this type of problem? Link to comment Share on other sites More sharing options...
Russdl Posted February 9, 2021 Share Posted February 9, 2021 @ProDave God what a nightmare. We have thin coat render in places but used a different system so I can't offer any insight to what may have happened to yours. I hope you get a speedy and satisfactory resolution. Link to comment Share on other sites More sharing options...
joe90 Posted February 9, 2021 Share Posted February 9, 2021 Sorry to hear of your grief, let’s hope you get a good resolution (like you did with the ASHP ?). Link to comment Share on other sites More sharing options...
Pete Posted February 10, 2021 Share Posted February 10, 2021 13 hours ago, ProDave said: The issue is one of trust. Even when "fixed" will i trust it not to happen again in 5 or 10 years? Yes gutted does not come close. this has been brewing up for a while and I have pushed it back relying on the plasterer saying he will sort it for a while as I could not do with the distraction while still busy building, but now is the time to face it and shout until I get a resolution. Hope you can get it sorted @ProDave. Just when you are nearly finished as well, fingers crossed for you Link to comment Share on other sites More sharing options...
ProDave Posted April 6, 2021 Author Share Posted April 6, 2021 I have appeared to hit a brick wall here. After lots of discussion and sending lots of photos the render supplier has come back and blamed it all entirely on poor workmanship, wrong beads used or too close to the ground. No offer of any help, no offer of materials to rework anything nothing at all. And they have done this entirely from photographs and not from a site visit to actually look at the problem for real. So where do i go from here? Just what am I supposed to do? How do i take this to the next level, legal if necessary? To say I am disappointed would be the understatement of the year. We presently have spent a lot of money on an external wall insulation and render system that has failed. No guarantee that if we rework it it will not fail again. No PROPER explanation of why it has failed. No suggestion what we should do to rework it in such a way that it does not fail again. I need the help of the forums collective wisdom to solve this. In the mean time until this is resolved I have a simple and clear message to any readers. DO NOT UNDER ANY CIRCUMSTANCES CONSIDER A BUILDING USING WOOD FIBRE EXTERNAL WALL INSULATION AND RENDERED WITH THE BAUMIT.COM THIN COAT SILIKON TOP RENDER SYSTEM. YOU PROBABLY WILL BE DISAPPOINTED AS WE ARE AT THE MOMENT. If / when we get a satisfactory resolution to this, I may amend that statement. I hope one day to be able to report how the company has been helpful, caring and we have achieved a satisfactory resolution. That day is not here yet. Link to comment Share on other sites More sharing options...
Declan52 Posted April 6, 2021 Share Posted April 6, 2021 Did they expand their reasons with a bit more information as in see picture abc that is bad workmanship because xyz etc. When they say wrong beads what is the difference between what you used and what they recommend and if you bought the system as a package they surely the correct beads would have been included. And what is too close to the ground and how could they come to that conclusion without an actual site visit and measurements taken. Link to comment Share on other sites More sharing options...
joe90 Posted April 6, 2021 Share Posted April 6, 2021 My heart goes out to you, I know ziltch about render unfortunately, I hope others that know more can help ?. (Is there a renderers forum???) @nod may know ! Link to comment Share on other sites More sharing options...
ProDave Posted April 6, 2021 Author Share Posted April 6, 2021 They blamed being too close to the ground and water wicking up the wall, yes all the way almost to the top of the garage wall. I find that hard to believe. Too close to the ground they quoted 300mm!!!! And they have blamed delamination above a door frame on the wrong type of drip bead. I have replied so I will see what they say. All the render material and beads were supplied in one order from the supplier I am discussing with. Link to comment Share on other sites More sharing options...
nod Posted April 6, 2021 Share Posted April 6, 2021 Not the best excuses I’ve heard Wrong bead We use all kinds of beads Even bellcast From the photo it doesn’t look to close to the ground I normally advise 150 minimum At the very least the supplier should stand the cost of the materials and scaffolding Theres no point in having a product guarantee if they are going to try and wiggle out of there responsibility Keep at them Dave My guess is they will probably back down when they realize that you won’t accept there explanation Link to comment Share on other sites More sharing options...
PeterW Posted April 6, 2021 Share Posted April 6, 2021 51 minutes ago, ProDave said: How do i take this to the next level, legal if necessary? If you do so, this thread will be hidden / removed under the forum T&Cs Link to comment Share on other sites More sharing options...
ProDave Posted April 6, 2021 Author Share Posted April 6, 2021 I have replied making it clear to the supplier (and hopefully more likely to get a resolution) that we have scaffolding and the plasterer is offering to rework for free, so it is only materials we need, and importantly technical input to ensure we have not genuinely done anything wrong. The base rail system is a 2 part PVC system by the same supplier that both supports and covers the bottom edge of the wood fibre board and provides a bottom bell cast drip bead. It also incorporates a section of mesh that gets pushed into the base coat. You would have thought that would stop any rain bounce getting in and wicking up. I have not peeled off any affected areas to look, I wanted to leave that until the company rep was here to see for himself. Link to comment Share on other sites More sharing options...
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