My 1860’s house has solid brick walls that have been covered with a sand / cement render followed by a tyrolean finish. I want to paint them with an exterior emulsion to reduce dampness when the walls are subject to heavy rain. They also have some fine cracks but the render seems essentially sound.
One painter I have spoken too would recommend a water based exterior emulsion, but another favours a solvent based pliolite paint. Would the latter be as breathable? I can’t find much info on breathability of pliolite paint.
What would you recommend?
Pliolite paint is formulated for application when there is a likelihood of rainfall within a few hours. It is, by nature, less breathable than regular masonry paint and has no performance benefits. Any painter who doesn’t know this ought not be allowed within a mile of your property.
It sounds like your walls are taking in a lot of moisture and you really need to address the cause of this first. The fine cracks you mention will need to be properly repaired first. If the walls are still taking in so much moisture it may be worth considering a solution that allows the walls to breathe rather than trying to make them water-tight. The solution to this involves both sides of the walls – not just the outside.
The SPAB publication ‘Breathability & Damp‘ is well worth a read.
Ordinary water based masonry paint is the most economical solution but not ideal.
Hi. I’m about to paint a garage that has been rendered – smooth finish. Built about 5 years ago but never painted. Confused with advice. What should I use to seal it? It’s not particularly flaky. some say water down masonary paint others say don’t. Some say use old undercoat to start first layer. Any advice? Had someone to paint my side of neighbour’s garage years ago and he used tons of tins of paint, but that wall was rough surface.
Use masonry paint. Thin the first coat so it soaks into the surface. Apply further coats straight from the tin; you can thin it a bit to ease application but don’t over do it. A rough surface may take a lot more paint to cover than you expect, especially if it hasn’t been painted before.
I want to paint the outside of my late Victorian terrace. It has not been painted before so I will be painting onto a rendered surface.
I cannot find out for sure but i am assuming because of the age of the building (It was built in 1901) that the render is lime and sand? is that a safe assumption. Although the decorative mouldings certainly look like cement to me so I wonder if its a bit of both. Is there a way to tell?
My question really is. Do i need a stabiliser? if so what one would you recommend and also would B&Q’s Valspar masonry paint be any good for this job?
I’m concerned about its breathability, I currently don’t have a jot of damp in my house and certainly don’t want to create a damp problem by sealing the house.
You’d need to have a sample analysed to ascertain if the render is lime based for sure but, given the date, it is a fair assumption. The mouldings could be a different material but it doesn’t really matter in this instance.
You don’t need a stabiliser. A thinned coat of masonry paint is an ideal primer. You only use stabilising primer on small areas if they are crumbly or friable. In most cases this isn’t necessary and using a stabiliser on a large area will just stop any moisture escaping.
The Valspar masonry paint is perfectly OK.