Persuade me please

[Bex]

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

[joe90]

@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

[SteamyTea]

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.

[Roger440]

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?

 

 

[Iceverge]

Have you considered getting EWI in the wall whilst you’re at it?  you may even get a grant. 

[Cpd]

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. 

[SteamyTea]

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?

[nod]

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 

[Roger440]

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.

[Brickie]

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. 

[Roger440]

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?

[nod]

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 

[Roger440]

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?

[SteamyTea]

There is a unit for breathability.

 

GNs/kg.m

 

Ask manufactures what the number is for their coatings.

[nod]

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 

[Bex]

On 05/02/2022 at 22:23, Roger440 said:

 

Does it have a DPC?

 

 

Yes it does 

[Bex]

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, 2022 by Bex