February 5, 20224 yr I will need to replace old wet and cracked sand/cement render on my Victorian terrace gable end in the next 12 months. Its a big job so not a decision I want to make lightly I have been advised (on here and by some builders) on ONLY accepting lime based render as it is a Victorian build....however, finding someone to do this has proved painfully impossible! I must have contacted 7/8 people and everyone wants to talk me out of it. A recent proprietor for silicone based render told me that this product is breathable and just as suitable for older properties. He also said that internal wall plastering doesn't allow for breathability and so I woudn't be avoiding the problem completely by getting lime based render anyway. Please help in my decision making. How hard do I need to pursue Lime based render over newer silicone/ k-rend etc and if I DO continue the search, any ideas how to find a company that will actually be willing to do it? thanks in advance
February 5, 20224 yr @Bex welcome, you don’t show where you are, if near Bristol I can recommend someone. Lime is breathable and better fir older properties, others will be along shortly to give further advise
February 5, 20224 yr Hello. If you ventilate the inside of a house properly, there is no need to go the lime route. Lime and cement render are not drastically different in breathability. And with cement based, it will at least set hard enough this decade.
February 5, 20224 yr 36 minutes ago, Bex said: I will need to replace old wet and cracked sand/cement render on my Victorian terrace gable end in the next 12 months. Its a big job so not a decision I want to make lightly I have been advised (on here and by some builders) on ONLY accepting lime based render as it is a Victorian build....however, finding someone to do this has proved painfully impossible! I must have contacted 7/8 people and everyone wants to talk me out of it. A recent proprietor for silicone based render told me that this product is breathable and just as suitable for older properties. He also said that internal wall plastering doesn't allow for breathability and so I woudn't be avoiding the problem completely by getting lime based render anyway. Please help in my decision making. How hard do I need to pursue Lime based render over newer silicone/ k-rend etc and if I DO continue the search, any ideas how to find a company that will actually be willing to do it? thanks in advance Does it have a DPC?
February 6, 20224 yr Have you considered getting EWI in the wall whilst you’re at it? you may even get a grant.
February 6, 20224 yr 9 hours ago, SteamyTea said: If you ventilate the inside of a house properly, there is no need to go the lime route. Lime and cement render are not drastically different in breathability. And with cement based, it will at least set hard enough this decade. This is not always the case, I have a gable wall that was repointed with cement instead of lime and it’s a disaster…. It is very well vented on the inside but it’s like a sponge now. The only way forward for me is to either re point the wall or clad it. @Bex don’t rush into making a decision, continue to look into the matter and be 100% sure of what is needed before laying out hard earned cash.
February 6, 20224 yr 35 minutes ago, Cpd said: This is not always the case, I have a gable wall that was repointed with cement instead of lime and it’s a disaster…. It is very well vented on the inside but it’s like a sponge now. Interesting, probably needs more unpicking. Does if face South West, or is is shaded from sun and wind? when you say well ventilated on the inside, do you mean in the room, or in a cavity? Was the right mix of render used?
February 6, 20224 yr I run a rendering company and often use lime plaster Always internal now Your builder is right All the through coloured renders are breathable and will out perform a line based render and can be made to look exactly the same finish
February 6, 20224 yr 2 hours ago, Cpd said: This is not always the case, I have a gable wall that was repointed with cement instead of lime and it’s a disaster…. It is very well vented on the inside but it’s like a sponge now. The only way forward for me is to either re point the wall or clad it. @Bex don’t rush into making a decision, continue to look into the matter and be 100% sure of what is needed before laying out hard earned cash. Cladding it wont make it less wet. Just cover it up and arguably make it worse.
February 6, 20224 yr 4 hours ago, nod said: I run a rendering company and often use lime plaster Always internal now Your builder is right All the through coloured renders are breathable and will out perform a line based render and can be made to look exactly the same finish There are even brick effect render systems available,doesn’t always look great around openings but not a issue for you on a gable.
February 6, 20224 yr 9 hours ago, nod said: I run a rendering company and often use lime plaster Always internal now Your builder is right All the through coloured renders are breathable and will out perform a line based render and can be made to look exactly the same finish What renders are these? Do you know the sd value and MVT values?
February 6, 20224 yr K rend is a good place to start SD is more likely applied to paint Lime render on the exterior of a building will soak up water like a sponge Modern renders Whilst breathable will let the building breath But the silicone in them will repel water
February 6, 20224 yr 1 hour ago, nod said: K rend is a good place to start SD is more likely applied to paint Lime render on the exterior of a building will soak up water like a sponge Modern renders Whilst breathable will let the building breath But the silicone in them will repel water Just about everything is breathable. Its a term bandied about by all the manufactuers. The question is to what extent. What makes you believe it matches lime in this regard?
February 6, 20224 yr There is a unit for breathability. GNs/kg.m Ask manufactures what the number is for their coatings.
February 7, 20224 yr 15 hours ago, Roger440 said: Just about everything is breathable. Its a term bandied about by all the manufactuers. The question is to what extent. What makes you believe it matches lime in this regard? 40 years of working with lime mortar
April 14, 20224 yr Author On 06/02/2022 at 01:20, Iceverge said: Have you considered getting EWI in the wall whilst you’re at it? you may even get a grant. Yes - I have considered it. Not sure I’m eligible for a grant though. Would be great if you could explain the difference if I do get EWI. Does it then matter what render I have on the outside when there is EWI in place? Edited April 14, 20224 yr by Bex
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