[Closed] BreathableMasonryPaintTrackWhoAmIKidding? info needed

Clearly the world has bigger problems this morning.

Look for silicate mineral paints. If you're painting direct onto bare masonry you could also use limewash.

At this time of year I suspect the extra prep needed for silicate just risks getting everything wet in the next rainstorm. It's really a question of Pliolite now or Acrylic in the spring. Which comes down to, is really much difference in breathability between Pliolite and Acrylic?

Information from a few years back - when I sold such paints...so I may be way out of date.

What is currently on? Is it already painted or are you re-rendering or pointing?

Europe has lots of silicate / breathable paints, and cost very little extra to our acrylic paints (euro/gbp dependent 🙁 )

[url= http://www.keimpaints.co.uk/ ]Keim[/url] was the recommendation from our lime supplier if we wanted colour. Otherwise limewash costs pennies per bucket to make up and is surprisingly effective. You can mix fat or oil into it to make it more weatherproof.

Is your house even lime rendered?

It's rendered but I don't know what with. I doubt it's lime... how would I tell? I want breathable paint because the wall had damp probs once and I want to make sure it doesn't get them again.

Generally lime isn't quite as rock hard as cement render, also it won't hold an edge, so you would normally have rounded corners on projecting edges.
Breathable paint over damp won't do anything if you dont fix the cause of the damp in the first place.

So, no actual numbers out there on whether weathershield is meaningfully more breathable than pliolite?

I don't think breathable paint is sufficiently breathable to make any difference with regards resolving damp problems.

The problem is more likely to be something to do with condensation ie from the inside, or construction ie bridged cavity (if it has one), damaged rainwater goods etc.

More info on the construction and substrate the paint is going on will help to identify the right solution.

Rich.

The substrate is ordinary render. There aren't damp problems currently, but there have been in the past; they were probably caused by bad render on the outside, which was since replaced, also condensation in the kitchen, which has since had an extractor fan fitted. But I want to make sure I do the right thing with respect to keeping it dry in future.

I can't be persuaded that any paint could possibly let moisture out, and yet magically stop water getting in. The whole point of painting render is to keep it waterproof isn't it.

As stated above if damp is getting in via the render then there either a cavity bridging issue or gutter problems. Whats the contruction, how olds the house? Is there a cavity in the walls?

On a modernish property just go with weathershied and forget about breatheable 🙂

Plenty of fabrics can do it, why not paint?

Condition ok, house about 100 years old, no cavity.

I thought weathershield was meant to be breathable - are you telling me it isn't (meaningfully)? then I might as well go with plyolite now rather than wait until spring for a dry enough week to weathershield it?

Assuming the work isn't urgent, what's better long term, plyolite or weathershield?

I think the idea with lime render is that it's always on a spectrum between dry and slightly damp with the weather so having a breathable paint allows this.

with cement its waterproof unless it cracks or theres a leak around a window seal or similar. If water gets in behind it then it cant escape/ tries to escape inside and causes damp. Old properties with stone walls are never totally "dry" like a new build would be

Bottom line; If you have cement render as it would seem, it wont make a chuff of difference what you paint it with, it's still non-breathable.