Exterior render painting prep

[b21playa]

Hi folks

Need to paint the cement based render in my house which is starting to flake. It looks to be a plasticy based paint.

What is the best prep method to remove the loose stuff, there’s a fair amount of wall space???

Also any recommendations on paint to use to repaint it.

Thanks

 

[michealangelo]

I always used to power wash exterior pre painted render to give a good key and get rid of any nonsense

I would use some oil based stabilising solution on any bare patches after you have tried to get rid of any flaking material

If you are painting this time of year I would use leyland truguard pliolite masonry paint

It's solvent based .....as with all surfaces it's best to thin it ...with the right solvent ...usually white spirit to both ease the coat in the cold weather and to get the paint to bond to the wall

I wouldn't over do it ......a 5 litre tin would be thinned adequately with about 250 to 300 mil of spirit

Take time to blend it properly

Get that first coat on , after the stabiliser has dried ......then DO NOT recoat until it's dry ....the tin should advise but I would leave it at least 12 hours ...therfore overnight

This coat will be tough to get on but the next coat .....undiluted ...should fly on

Depending on the state of the walls a thin coat and top coat can do the job

For crappy walls and colour changes it will take 3


If you want to go through the water based route ........much preferred as it allows walls to breathe as they should ....then again wash down walls if they look rough , stabilise patchy areas with stabilising primer , allow to cure then thinned first coat of whatever masonry paint you prefer

The major brands are all much the same or certainly were in my day ........sand tex, leyland , etc

Thinning first coat would be about a pint of water to 5 litre tin

Then follow up with coats of undiluted paint till get your finish

If the walls are smooth or semi smooth the job will be easier than if it's rough or pebble dash

I used to always use ordinary masonry paint as it goes on a lot easier than the thicker , textured stuff .....which has its uses

 

[michealangelo]

You CAN get away with applying masonry paint direct to reasonably good exterior walls and most decorators .....I use that word loosely...seem to

But that's bad practice

External walls are like internal wood ......if a decorator turned up at your house and just slapped paint on wood without keying it or preparing it you would be mad to pay him

For the sake of a mornings work a quick wash down will clearn the surface and make it easier to get that first coat on ......which as in all decorating is the most important

At the very least ensure any obvious dirt and green moss growth is removed