Fresh Render needs sealing?

[JohnBoyII]

I had the outside walls cement rendered about 9 months ago and want to paint it with some (Dulux Weathershield) masonary paint.

The painter says that its all got to be sealed first otherwise the paint'll peel off in a couple of years. The Dulux people say that you can't seal new render because the paint won't stick, they suggested thinning down the first coat (5 water: 1 paint) and applying two coats.

Whos right and why?

 

[breezer]

dulux, becuse they make the paint

 

[Zampa]

Dulux....

Just thin the first coat down by 20% its excactly the same as mist coating plaster walls.

The first coat (mist) locks onto the surface...it soaks in, as opposed to sitting on the surface.

What was your decroator thinking of sealing it with?....let me guess..... stabilising solution?...or thompsons water seal?

 

[JohnBoyII]

I spoke with the blokes in B&Q and Wickes and both suggested sealing it first. The painter didn't say what he wanted to seal it with but the bloke in B&Q suggested thinning down Unibond Exterior PVA, said that he'd just his place the same way. Apparantly you can thin down the first coat of paint but then you'd still have to put on two further coats, so three coats of paint in all. Does that sound right because I thought that if you applied a thinned down first coat you'd only needed to apply one full coat of paint on top. Or have I just got the wrong end of the stick?

 

[Zampa]

Dont take any notice of staff in those shops...clueless.

Its down to how you ask the question...if you asked a 'closed question' like...." do i need to seal the walls first"....they will say yes....

If you ask " what paint system should I use in this situation they will be knackered!

The long term aim is a successful paint system...i.e one that will last...not one that coveres in the minimum amount of coats.

Its far better to apply two thinned coats and one full one than two thick coats..

Unless the wall is underbound and friable..(dusty and chalky) then it will not require sealing.

And beleive me using exterior unibond really is a terrible answer to give.

I have been decorating for 27 years and a lecturer for four of those and i have never heard of using pva.

If the wall is dusty then you should use stabilising solution...

Take the advice of the people in dulux....not that of people who work in shops...its like wanting to know how to bake a cake and asking the person stacking flour in Tescos.

http://www.dulux.co.uk/webapp/wcs/s...dView?storeId=10752&catalogId=10051&langId=-1

 

[JohnBoyII]

Zampa, just a short note to say "Thanks". I took your advice and went for the three coats as you'd suggested. The painter's just finished and it all looks smashing. Cheers!

 

[Zampa]

No problem...i think its worth mentioning here that a lot of confusion is down to terminology

Your decorator may have bene right in what he meant.....but not what he said.....and that confused you.

The word sealer or to seal something often comes up..and is very misused or misunderstood.

I had an horrendous time with a customer once who said her damp problem (which turned out to be because of wall ties) was down to the fact that i hadnt 'sealed' the previously painted walls with stabilising solution prior to painting them

I tried to explain why you dont put stabiliser on walls that dont need it and it isnt a sealer anyway......but no....the man in hard ware shop (who had sold her enough stabiliser to paint the street) had told her...blah blah blah..

Therefore...its important to understand what people mean.....in this case the first coat was to 'prime' the surface....the rest sealed it from the elements.