Paint or not over NHL render

[larry]

We have had our house re-rendered with NHL. Very happy with how it looks but:

A. Any risks with not painting it at all?
B. If we paint it, any problems with Silicate paint? (Would take longevity over limewash)
C. If we do paint it how long should we leave it (it's a few cm thick in places over soft brick)

Thanks!

 

[housewinnie]

Limewash every time. Cheap and easy to apply

 

[larry]

Didn't I read somewhere first go needed four coats??

 

[Kearn]

Didn't I read somewhere first go needed four coats??

Yes, 3-4, but equally a paint will need probably 3, the first being a 50:50 diluted version as the fresh lime will be super thirsty.

 

[RBailey]

Didn't I read somewhere first go needed four coats??

Yes but its like milk, it goes on really easily and quickly.
The multiple coats isn't as panful as it sounds.

 

[Kearn]

Yes but its like milk, it goes on really easily and quickly.
The multiple coats isn't as panful as it sounds.

What you do need though is patience!

@larry
You need to be waiting 24hrs between coats so the previous layer can fully form with the wall, adding another layer too quickly will ruin the adhesion and finish. Limewash is unlike a paint, in that it it isn’t a surface covering, it bonds with the substrate beneath.

It’s also immensely cheap, as you’d be mad to not make it yourself. If you buy it, you’re basically purchasing water and then paying huge sums to transport said water to you.

 

[larry]

What about the "do nothing" option?

And how long should I wait before using limewash?

 

[Kearn]

What about the "do nothing" option?

And how long should I wait before using limewash?

Not necessarily an issue, I left some exterior panels bare as I liked the finish and colour. They were well protected and on the non weathered side though. If they weren’t, I’d be inclined to protect the lime a touch with a surface finish of lime wash, it becomes the sacrificial layer then. You don’t have to keep updating it annually though, could just let it weather nicely…

That said, NHL is a very hard setting render, so unlikely to get damaged, more likely to shrink away or crack once it really sets hard in the next 5-10 years.

Limewash you don’t really have to wait at all - render will continue to carbonate through the limewash, although obviously wait until you won’t be impacting the surface finish. Limewash wants a fairly stiff brush for application, you don’t want a stripey pattern in the surface of your panels/wall!

 

[malcolm]

I can't think of any risks in not painting it at all. But if some paint is needed limewash is perfect as above.

 

[larry]

Thank you everybody. All the advice here has been really helpful - very much appreciated.