Masonry paint in winter - Sandtex 365 - any good for old house/solid wall?

ChasingtheWelshdream

Hi all - to elaborate on the title :-)

We currently have scaffold up to ridge level for roof repairs. As this is not cheap, we had wanted to take advantage of the access and paint the masonry at the same time. This is a 3 storey gable wall - we really don't want to pay £££ scaffold again for a while if we can help it. 

Anyway, life happens and we are only now in a position to get started. Of course, the weather now poses a potential problem - cold/damp/frost.  The masonry on that elevation isn't actually in too bad a condition, and not the complete end of the world if we can't paint - but we won't be scaffolding/accessing again for several years hence (we hope!)

So, I'm looking for any experience/opinions/reviews of any paint that would be suitable for applying this time of year - or not. I've found Sandtex 365, which claims to be suitable for cold weather and quick water resistance. But, it's solvent-based and our house is Edwardian, making me wary...

The render is rough-cast, and we have no idea what paint is on it currently, but I'm wary of potentially wrapping the house in an impervious plastic film and introducing damp/breathability issues. Being rough-cast, it will also take a long time to paint, so the last thing we want is for the paint to fail.

Any and all thoughts welcome - thanks in advance!

stuart45

Is the rough cast OPC or lime based render?

ChasingtheWelshdream

I’m not completely sure to be honest. A couple of areas are a dark grey and quite hard, but that’s all I can ascertain. The few areas of exposed facing brickwork use lime mortar.

The previous owner ‘helpfully’ had a chemical dpc, and covered the downstairs floor in latex, causing issues which we are slowly rectifying, hence my reticence to inadvertently cause more damage.

Here’s a couple of exposed areas where the paint has failed - albeit on a different elevation that we can reach with ladders next year. The paint where the scaffold is, is not as bad.

cymruchris

It's currently too cold and damp to effectively apply masonry paint as I recently found out. I spent a whole afternoon painting a wall with Sandtex - a day with a blue sky but a bit chilly - and then in the early hours of the next morning it rained, causing it all to wash off. (The packaging said dry in an hour)

Following a complaint, the rep called me and said that the best time to paint exterior walls is Feb-Oct - on days when the temperature is above 8 degrees, and there's not been rain for a couple of days. 

They gave me a couple of tins of Sandtex extreme for free which was nice of them - but they reiterated that I should wait until the temperature gets warmer before using it for best effect. 

With it being particularly cool and damp right now - I'd probably hold off - otherwise although you're saving money - you might end up spending money if it doesn't end well. 

ChasingtheWelshdream

See, that’s my fear. If we could access the elevation without scaffold, or even the highest point with a cherry picker, we would not be considering it.

But as the scaffold is up, at a cost of over £2k and counting, we will not be shelling out again for the foreseeable.

The other option is to simply give the paintwork a really good clean and forget about it for a few years.

The front/rear elevations are much more easily accessed and will be painted next year.

Mickey666

stuart45 said:

Is the rough cast OPC or lime based render?

ChasingtheWelshdream said:

I’m not completely sure to be honest. A couple of areas are a dark grey and quite hard, but that’s all I can ascertain. The few areas of exposed facing brickwork use lime mortar.

Place a few clippings in vinegar (or other mild acid) - lime render/mortar will ‘fizz’ slightly, OPC won’t.

Sounds like you understand the importance of not compromising breathability in old buildings unlike the previous owner who seems to have done all the wrong things.  I can understand the temptation to get the most value out of the scaffolding but exterior painting in winter is always going to be risky.  Draping the walls with hessian might keep off any frosts while the paint dries/cures but it’s a bit of a desperate measure to be honest.

ChasingtheWelshdream

I’ll chip a bit off and see 🙂

Terrysdelight

Johnstone's Pliolite Masonry Paint is excellent and can be applied in very cold weather and also, it is rain resistant in about 15 minutes I think.   I had an outside painted with this product and snow was on the ground.  Highly recommend.

ChasingtheWelshdream

I just thought I'd pop back on and update. 

I had checked the render for lime and couldn't detect any - definitely a cement based coating. We're unsure if the roughcast is original or not, but the adjoining semi and many similar houses in the street are the same. Anyhow, although breathable paint would be our ideal, the existing paint is most definitely not, and has not given any damp issues. 

Anyway, the repairs went on and on, and we had pretty much abandoned any idea of painting with many bouts of snow and seemingly unceasing rain. DH had been dashing up during any brief dry spells to repair and repaint the soffits/barge boards, so we'd done something at least.

Then last week we had a break in the weather - one solitary day of the dizzy heights of 8 degrees. In classic 'abandon the kids to the TV all day' parenting style, it was all hands to the deck and we managed to reach everything inaccessible without scaffold. 

We used Johnstone's Pliolite Masonry and it really was fine. Easy to apply, good coverage and a nice chalky/matt finish. By the time the evening drizzle arrived it was touch dry. And in the snow the following day, it remained stuck to the wall. Scaffold comes down tomorrow and we can then do the final few bits. 

We chose Johnstone purely because it was in stock at our local builders merchants. I'm very pleased we managed it as it really does smarten everything up. :-)