Browse Forums Owner Builder Forum 1 Aug 14, 2019 9:56 pm Hi all, Trying to build a high performance house where product of choice for wall construction lists "breathability" as one of the major advantages. So, to keep the entire wall system "breathing active" have been told to steer away from standard acrylic paints, as they're "film forming" and not breathable. Just wondering if anyone here has encountered mineral (silicate/limewash), or clay, or silicone resin emulsion paints? These other paints are so rarely used, it's really hard to get any direct comparison between them... Appreciate any input into this. Kevin Re: Non-standard (acrylic) "breathable" paints 2Aug 21, 2019 11:11 am Hi, I had some dealings with the Victorian Keim Agent many years ago. A sample was given to me and applied on a house I was working on. Don't know the outcome from there. After examining a variety of the products Porters, Keim etc it was my conclusion that they still have acrylic in them. A recent project used a Porters product and to me it was just an acrylic paint probably at a low % in can. Porter's owned by Dulux since 2015. Is your building a non cavity construction? thanks Re: Non-standard (acrylic) "breathable" paints 3Aug 22, 2019 9:49 pm Hi there, Thanks for the reply. Anyway, yes the build is non-cavity construction using Durisol blocks. It claims to be "vapour active" (allows adsorption / release of moisture), therefore I'm after a finishing product that does not impede the movement of moisture into/out of the walls. Hopefully, someone else with more experience can chime in too. Kevin Re: Non-standard (acrylic) "breathable" paints 4Aug 23, 2019 12:18 am One way is to consider silicon render which already has paint in it. For internal, you can go with clay paints or Keim breathable paint, but a lot will depend on the breathability of your internal render though. Remember, that paint is relatively very thin layer (few microns), so doesn't really have much impact on "breathability". From the scientific article I was e-mailing to you the other day: "As regards hygroscopic qualities, these are not really relevant as regards the paints themselves as they are so thin. However it is assumed by many people that a paint’s vapour permeability seriously affects the hygroscopic performance of the rest of the wall. In practice this may not actually the case. This was the surprising result that Minke obtained, when he was looking at how finishes affected the hygroscopicity of an unfired clay wall. He tested a number of finishes including standard emulsions and distempers. The only products that significantly reduced the hygroscopic performance were double boiled linseed oil and pure latex. These both have an extremely high vapour resistance. Most standard wall paints, according to this research will, therefore, have relatively little effect on substrate hygroscopic performance. However these results are countered elsewhere, and this is one area that certainly requires further research." Re: Non-standard (acrylic) "breathable" paints 6Oct 27, 2020 5:42 pm hi I realise this post is over a year old now and you've probablhy already painted your walls. However for future reference... Im looking into this very question atm. From extensive research, Murabond has some excellent-value fully vapour permeable Mineral Silicate Paint - cost is around $28/L but mineral silicates are the bees knees in permeability if youre looking for a high-performance and high wear permeable paint with solid colour that will last for years. It chemically bonds with the substrate Murabond also do a limewash paint. They're a fully australian-owned and operated paint company, family owned. Porters now owned by Nippon Points i believe. May as well forget about Porters now they've sold out to fashion and have no information available on original performance of their paints. The interno lime paint appears to now be acrylic based, they cannot provide information that states otherwise Re: Non-standard (acrylic) "breathable" paints 8Oct 28, 2020 10:00 pm Debunk hi I realise this post is over a year old now and you've probablhy already painted your walls. However for future reference... Im looking into this very question atm. From extensive research, Murabond has some excellent-value fully vapour permeable Mineral Silicate Paint - cost is around $28/L but mineral silicates are the bees knees in permeability if youre looking for a high-performance and high wear permeable paint with solid colour that will last for years. It chemically bonds with the substrate Murabond also do a limewash paint. They're a fully australian-owned and operated paint company, family owned. Porters now owned by Nippon Points i believe. May as well forget about Porters now they've sold out to fashion and have no information available on original performance of their paints. The interno lime paint appears to now be acrylic based, they cannot provide information that states otherwise Hi, thanks for chiming in. Not late at all, walls aren't up yet... But I still haven't found my answer, despite having spoken to + email correspondence with Adrian Thomas who is currently the raw materials supplier to Murobond for their mineral silicate paint, who also used to manage Wacker (produces silicone resin emulsion paints)... Anyway, I know it's a toss up between Murobond (silicate), or getting Edgar from SupaCoat to formulate a silicone resin paint for me. Kevin Re: Non-standard (acrylic) "breathable" paints 9Oct 28, 2020 10:15 pm supa007 Debunk hi I realise this post is over a year old now and you've probablhy already painted your walls. However for future reference... Im looking into this very question atm. From extensive research, Murabond has some excellent-value fully vapour permeable Mineral Silicate Paint - cost is around $28/L but mineral silicates are the bees knees in permeability if youre looking for a high-performance and high wear permeable paint with solid colour that will last for years. It chemically bonds with the substrate Murabond also do a limewash paint. They're a fully australian-owned and operated paint company, family owned. Porters now owned by Nippon Points i believe. May as well forget about Porters now they've sold out to fashion and have no information available on original performance of their paints. The interno lime paint appears to now be acrylic based, they cannot provide information that states otherwise Hi, thanks for chiming in. Not late at all, walls aren't up yet... But I still haven't found my answer, despite having spoken to + email correspondence with Adrian Thomas who is currently the raw materials supplier to Murobond for their mineral silicate paint, who also used to manage Wacker (produces silicone resin emulsion paints)... Anyway, I know it's a toss up between Murobond (silicate), or getting Edgar from SupaCoat to formulate a silicone resin paint for me. Kevin Would love to learn from your experience. I think you are talking about topcoat render though (for outside), not paint? Silicon silicate renders are the best. Re: Non-standard (acrylic) "breathable" paints 11Oct 29, 2020 4:56 am PS if you're looking for a render (interior of exterior) why not go for lime and sand? Use NHL2 or NHL3 Hydraulic lime (eg Tower lime imported from UK) an entirely different beast to hydrated brickies lime. NHL2 or 3 gets you a tough, economical and very easy to apply diy material Re: Non-standard (acrylic) "breathable" paints 12Oct 30, 2020 8:50 pm Debunk PS if you're looking for a render (interior of exterior) why not go for lime and sand? Use NHL2 or NHL3 Hydraulic lime (eg Tower lime imported from UK) an entirely different beast to hydrated brickies lime. NHL2 or 3 gets you a tough, economical and very easy to apply diy material Hi Debunk, do you have any rough cost / m2 for NHL? Re: Non-standard (acrylic) "breathable" paints 13Oct 31, 2020 11:45 am I bought 20kg NHL2 for around $50 from Thorhelical in Sydney. Remember this is mixed with sand (ratio approx 2:3 from memory) so it goes a long way. Beats Rockote lime render hands down for value, and easier to use, more buttery Re: Non-standard (acrylic) "breathable" paints 14Oct 31, 2020 11:47 am You can look up the specifications for rockcote lime render, to get an idea of how far the material goes. But remember that rockcote is already mixed with sand so you're paying top dollar for sand as well. Can't give you square metre rate per sae without looking up my notes, from memory the ratio is per volume not by weight, would have to confirm this Re: Non-standard (acrylic) "breathable" paints 16Nov 01, 2020 10:55 am Mirrmu83 Murobond has <10% acrylic polymer. See safety sheet. Film forming. Are you suggesting the lime mix as a basecoat or finish coat? Rockcote Lime Plaster is a finishing coat. So, are there any non-film-forming paints then? Would Keim as the original mineral silicate paint be non film forming? Re: Non-standard (acrylic) "breathable" paints 17Nov 01, 2020 8:30 pm I don't believe so. The problem is customers want to be able to choose from 3000+ colours like if selecting a Dulux or Taubmans colour. It just doesn't happen with "mineral" based products. So they introduce an acrylic system which can utilise typical paint tints. To achieve a breathable wall is very easy. Use sand, cement and lime renders. An admixture of boncrete at 1:10 can be used for water. Oxide is added for colour. If polystyrene blocks/cladding is used then breathability will reduce as more polymers are added to render to make it stick to polystyrene. Straw bale industry would be a good place to investigate. Re: Non-standard (acrylic) "breathable" paints 18Nov 01, 2020 11:24 pm As I already mentioned above, what really matters is that even for typical outdoor emulsion paint vapour resistance (r) can be quite high (15,000) when comparing to lime (75) or sand-cement (100) plaster and silicate paints (250) or 5 coatings of pure limewash (250), the overall thickness of a paint layer is comparatively many many times thinner (typically only 100-120 microns) and, hence, it won't be providing a significant impact on the overall vapour permeability of the complete wall system in general. Re: Non-standard (acrylic) "breathable" paints 20Nov 02, 2020 2:37 pm Mirrmu83 Thats incorrect, acrylic paint will form a film and not breathe. According to the laws of physics, every single substance can be vapour permeable (as it is just about allowing water vapour molecules to pass through the structure via diffusion, this is mainly what you refer as "breathable", although there are some other properties affecting overall breathability too). Even with exteremely resistant waterproof epoxy coatings, the process is still (slowly) taking place. The thinner the structure is, the more chances for water molecules to pass through. At only 120 microns of thickness, the vapour resistivity (literally defining the amount of water vapour passing through the material over certain amount of time) of a thin layer of outdoor emulsion paint will be MORE THAN TWICE lower than vapour resistivity of 100 mm of brick. For indoor emulsion paints it will be virtually insignificant as indoor paints have 5-10 times lower vapour resistivity than outdoor paints. What is more important is the point at where the vapour permeability becomes lower (such as installing OSB sheet to the outside of frame, so the framing remains exposed to the water vapour for extended periods while it is passing through OSB) and at some stage under certain conditions the frame timber starts to rot. If it is simply passing through brick, layer of render and paint (as it is doing anyway), it is certainly much less concern. The yellowing mainly occurs to white or very light colours. 1 2922 Hi Alex, Thanks for the reply again. I had a chat with the builder, he said he will use primer, then hydrotec which comes with colour and sealer as well. A Renderer I… 12 18013 Suggestions please for acrylic rendering Color to match austral brick urban one pepper. Pic for reference. Thanks 0 5063 |