Exterior pebbledash painting - Advise required please

[ripperuk]

@misterhelpful - I don't know about powdery, but the render is slowly crumbling...i.e. the pebbles are slowly falling out the render.

@motorbiking - Which paint sprayer was it? Wouldn't the spray end up going on the doors and windows below?? how did you protect lower areas if you sprayed higher?

 

[misterhelpful]

@ripperuk

If the actual mortar is crumbling and causing the stone chips to fall off then a stabilising solution may be beneficial. If it's just the chips that are falling away, you should be fine with just painting - as I mentioned initially, all dashing has chips that fall off, especially when new or after a spell of hard weather. That said, it would be fine to use stabiliser on pebbledash anyway, but I just feel it may be an unnecessary expense when, from countless years of experience, I know diluted paint will do the same job.

The reason that stabilising solution is usually recommended for powdery/flaky surfaces is that it can be absorbed better into the substrate, helping bind everything together. If it is used on a smoother surface which isn't powdery/flaky/absorbent, i.e., not pebbledash, it is more likely to just leave a film on the surface which can sometimes cause adhesion issues when it come to applying paint, so that is where it should be avoided.

 

[ripperuk]

no worries misterhelpful. I'll take your advice and just stick with just diluted paint. Would using a spray paint be okay? If so, how can I protect the doors & windows from getting spray on them?

 

[ripperuk]

Oh sorry, I just forgot, you mentioned in the other thread that I should use Bedec Barn Paint, but what's the difference between that and Johnstone's Stormshield Pliolite???

 

[motorbiking]

@motorbiking - Which paint sprayer was it? Wouldn't the spray end up going on the doors and windows below?? how did you protect lower areas if you sprayed higher?

It was a very cheap low pressure high volume jobbie from b&Q, a bit like this : http://www.screwfix.com/p/erbauer-erb561srg-700w-hvlp-electric-spray-gun-220-240v/11628?kpid=11628

You need to check when buying as not all can work with masonry paint. You do need to dilute it a little.

To avoid over spray, you just get close when you are near a window or door. Its not like you are spraying a car and want a drip free, high gloss finish. any drips will easily soak in. Since the paint is water based, I just had a bucket of water and a sponge and wiped anything quickly. I did my whole house in a weekend. Easily worth the money. I'd have liked as bigger tank, as it takes a while to get the sprayer going right and once its working well you don't want to stop every 5 mins to refill.

Expect to bin it when you are done.

 

[ripperuk]

Thanks motorbiking. How many litres could your sprayer store compared to the link you've posted?

 

[motorbiking]

approx the same.

 

[ripperuk]

approx the same.

Hmm... You s your home pretty large?

 

[misterhelpful]

I could have flown there, painted it and been home by now!

 

[ripperuk]

Lol! So sorry misterrhelpful, I'm not doing the actual job straight away due to bad weather, so I thought might as well get an understanding of what to expect and do. My home is pretty large.. Semi-detached with 5 bedrooms, large double extension.

 

[misterhelpful]

Just kidding around.

 

[motorbiking]

5 bed detached -I can't remember the exact dimension ~ 60' x 55'. Its more about access than size, if you are working with a ladder it will take more time, I already had scaffolding up on 2 sides. When I was trying to find a sprayer, one that had a decent tank size and could do masonry paint. My purchase was aimed very much as a disposable tool, saved about £2k diying though.

 

[ripperuk]

@ misterhelpful - LOL! I thought so.

@motorbiking - You had scaffolding and it still took you a weekend with a sprayer? I'm surprised as I thought it would have been much quicker. I most likely will have to do one side at a time for each weekend and yes all the work will be done on a ladder.

 

[Chri5]

Use a sealer pre painting, some you can spray on.

The paint won't bond the loose stone, and brush painting will pull more dashing off. The sealer will also help the paint stick better.

My attitude to works like your want to do is to do it right, use the best material solutions and hopefully get more years out the job.

We all have different ways of working, but since you mentioned dashing falling, and crumbly surface texture I would still suggest a primer sealer.

£25 for 4 litres v 60 m sq cover.

I'd blow out the idea of spray (pun intended).

A. To get the same coat thickness will need half a dozen passes
B. Over spray
C. Wind
D. Masking off windows, gutter, doors etc
E. From ladders

Buy the best paint you can, minimum spec trade smooth masonry.

If the dash is low profile a long haired roller works well, otherwise its a mid or large masonry brush (get one that holds a decent volume of paint) and off you go.

Reason to consider brush size, it that a large one can be counter productive if you end up with fatique after an hours use.

Something you might want to consider (well I do this in London property due to pollutants).

Get a large pump spray make up some decent strength sugar soap, spray the dashing throughly and leave for an hour. Then wash down with a hose on fine spray and a soft brush (steal the dustpan one). Allow to dry out for 24 hours.

This process gives the best start for the new paint, clean oils away, and will take off dashing that will drop off anyway.