Hello,

I need to paint the concrete window sills and the window surrounds on my
roughcast kit bungalow near the Atlantic coast of the Isle of Lewis in
Scotland. They're painted at the moment but haven't been maintained for some
years. The sills I think have been done with some kind of matt external paint
and are crumbling but only very slightly and on the surface and not
sufficiently to require skimming. The surrounds have been done with something
more glossy.

The guy in the paintshop recommended a 3:1 water:PVA coat after scraping, and
then some Dulux Weathershield. He didn't seem to know much about SBR or
alternatives to that brand and type of paint.

Should I use PVA or SBR or something else? I thought for a while that maybe
he's right at least on the PVA score because a decent paint will soak into the
concrete which SBR being waterproof would hinder. I'd be grateful for advice
from some of the knowledgeable people here.

And what should I do about the surrounds?

Third question... The walls are roughcast and look mostly okay for the time
being although in places they are weather-stained and I plan to paint them. I
was thinking one coat of SBR followed by two coats of masonry paint. Does that
sound okay? Or would it amount to putting a vapour barrier on the cold side of
insulation and thereby muck up the ventilation something rotten? I'd like to
use paint that doesn't need to be recoated in the next 20-30 years.

Thanks in advance,

Harry

Well for that length of time I suspect the only thing that would work is one
of these professionally applied coatings. I'm not in an exposed area, but
this wallcoat stuff if done right seems to be very good. Not cheap but at
least to me only having two walls, cost effective.
Brian

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Blind user, so no pictures please!
"Harold Davis" wrote in message
...
Hello,

I need to paint the concrete window sills and the window surrounds on my
roughcast kit bungalow near the Atlantic coast of the Isle of Lewis in
Scotland. They're painted at the moment but haven't been maintained for
some
years. The sills I think have been done with some kind of matt external
paint
and are crumbling but only very slightly and on the surface and not
sufficiently to require skimming. The surrounds have been done with
something
more glossy.

The guy in the paintshop recommended a 3:1 water:PVA coat after scraping,
and
then some Dulux Weathershield. He didn't seem to know much about SBR or
alternatives to that brand and type of paint.

Should I use PVA or SBR or something else? I thought for a while that
maybe
he's right at least on the PVA score because a decent paint will soak into
the
concrete which SBR being waterproof would hinder. I'd be grateful for
advice
from some of the knowledgeable people here.

And what should I do about the surrounds?

Third question... The walls are roughcast and look mostly okay for the
time
being although in places they are weather-stained and I plan to paint
them. I
was thinking one coat of SBR followed by two coats of masonry paint. Does
that
sound okay? Or would it amount to putting a vapour barrier on the cold
side of
insulation and thereby muck up the ventilation something rotten? I'd like
to
use paint that doesn't need to be recoated in the next 20-30 years.

Thanks in advance,

Harry

In article ,
Harold Davis writes:
Hello,

I need to paint the concrete window sills and the window surrounds on my
roughcast kit bungalow near the Atlantic coast of the Isle of Lewis in
Scotland. They're painted at the moment but haven't been maintained for some
years. The sills I think have been done with some kind of matt external paint
and are crumbling but only very slightly and on the surface and not
sufficiently to require skimming.

Possibly masonry paint?

The surrounds have been done with something more glossy.

The guy in the paintshop recommended a 3:1 water:PVA coat after scraping, and
then some Dulux Weathershield. He didn't seem to know much about SBR or
alternatives to that brand and type of paint.

Sounds like a bad idea. PVA isn't waterproof - it's water soluable.
Even EVA (external PVA) isn't waterproof, except inside mortar mixes.
SBR is, but I don't know about longevity in highly exposed situations.
Dulux Weathershield doesn't last long on masonry (from personal
experience).

I don't have an answer, but I would have thought a masonry paint would
be most appropriate and hence longer lasting.

Should I use PVA or SBR or something else? I thought for a while that maybe
he's right at least on the PVA score because a decent paint will soak into the
concrete which SBR being waterproof would hinder. I'd be grateful for advice
from some of the knowledgeable people here.

And what should I do about the surrounds?

Third question... The walls are roughcast and look mostly okay for the time
being although in places they are weather-stained and I plan to paint them. I
was thinking one coat of SBR followed by two coats of masonry paint. Does that
sound okay? Or would it amount to putting a vapour barrier on the cold side of
insulation and thereby muck up the ventilation something rotten? I'd like to
use paint that doesn't need to be recoated in the next 20-30 years.

I think that's a bit of a challenge. For that sort of life, I
believe coloured renders are normally used.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

In article ,
Harold Davis wrote:
The guy in the paintshop recommended a 3:1 water:PVA coat after
scraping, and then some Dulux Weathershield. He didn't seem to know
much about SBR or alternatives to that brand and type of paint.

Should I use PVA or SBR or something else? I thought for a while that
maybe he's right at least on the PVA score because a decent paint will
soak into the concrete which SBR being waterproof would hinder. I'd be
grateful for advice from some of the knowledgeable people here.

With a masonry paint. you'd normally just thin it with water for a primer
coat, if the surface is absorbent.

I've just used Bedec which you can order from ToolStation. On advice from
here. Of course only time will tell if it lasts better than the previous
stuff - but it is certainly difficult to get the lid off a used tin. ;-)
But quite a bit more expensive than the common brands. It is said to
remain flexible and to 'breath' .

--
*Broken pencils are pointless.*

Dave Plowman London SW
To e-mail, change noise into sound.

Harold Davis writes:
Hello,

I need to paint the concrete window sills and the window surrounds on my
roughcast kit bungalow near the Atlantic coast of the Isle of Lewis in
Scotland. They're painted at the moment but haven't been maintained for
some

Third question... The walls are roughcast and look mostly okay for the
time
being although in places they are weather-stained and I plan to paint
them. I
was thinking one coat of SBR followed by two coats of masonry paint. Does
that
sound okay? Or would it amount to putting a vapour barrier on the cold
side of
insulation and thereby muck up the ventilation something rotten? I'd like
to
use paint that doesn't need to be recoated in the next 20-30 years.



I use a Stabilising Solution which is not PVA or SBR on masonry
https://www.toolstation.com/shop/Pai...olution/p75668

-

On Wednesday, September 27, 2017 at 5:12:11 PM UTC+1, Mark wrote:
Harold Davis writes:
Hello,

I need to paint the concrete window sills and the window surrounds on my
roughcast kit bungalow near the Atlantic coast of the Isle of Lewis in
Scotland. They're painted at the moment but haven't been maintained for
some

Third question... The walls are roughcast and look mostly okay for the
time
being although in places they are weather-stained and I plan to paint
them. I
was thinking one coat of SBR followed by two coats of masonry paint. Does
that
sound okay? Or would it amount to putting a vapour barrier on the cold
side of
insulation and thereby muck up the ventilation something rotten? I'd like
to
use paint that doesn't need to be recoated in the next 20-30 years.



I use a Stabilising Solution which is not PVA or SBR on masonry
https://www.toolstation.com/shop/Pai...olution/p75668

-

I'd soak the sills with a 2 part product which cures whatever the conditions. Fibreglass resin, Rustins Plastic Coating etc. Then skim with a 2 part filler (e.g. Profil from Toolstation). Then paint with anything you fancy, which should last forever because it will be on a non porous surface. IME no surface coating can cope with crumbly sills.