I have a strange problem with some emulsion painted walls. Must be 6 or 7
years ago since I decorated the hall & landing. I put up a dado rail and
painted above the rail a light green and below a slightly darker green. I'm
pretty sure that I sealed the walls first with some dilute pva. About a year
ago we first noticed some rough patches appearing in the light green
upstairs on the landing. Since then it's just got progressively worse. But
it's only the light green above the dado rail and it's only upstairs on the
landing. Everything is fine down in the hall, and the darker green below the
dado rail is ok up on the landing. The rough areas are where the paint is
flaking off. Not in big blisters - just very small rough bits.

I've never come across this before and I don't know what's causing it. I
don't think it was my preparation as the paint everywhere else is fine. But
if it's the paint, why isn't it happening all over - not just upstairs? The
walls are all internal walls so it's not damp from the outside or anything.
The problem is what to do about it. If I just sand the bits that are flaking
and repaint I'm worried that the old paint is just going to carry on
flaking. I get the feeling that I need to get all the old emulsion off the
walls and start with bare walls again.. Would this be the best thing to do
and how would I go about it?

TIA
John

Nodge presented the following explanation :
I have a strange problem with some emulsion painted walls. Must be 6 or 7
years ago since I decorated the hall & landing. I put up a dado rail and
painted above the rail a light green and below a slightly darker green. I'm
pretty sure that I sealed the walls first with some dilute pva. About a year
ago we first noticed some rough patches appearing in the light green upstairs
on the landing. Since then it's just got progressively worse. But it's only
the light green above the dado rail and it's only upstairs on the landing.
Everything is fine down in the hall, and the darker green below the dado rail
is ok up on the landing. The rough areas are where the paint is flaking off.
Not in big blisters - just very small rough bits.

I've never come across this before and I don't know what's causing it. I
don't think it was my preparation as the paint everywhere else is fine. But
if it's the paint, why isn't it happening all over - not just upstairs? The
walls are all internal walls so it's not damp from the outside or anything.

Often it is caused by some damp, it doesn't need much to make it flake.
Is it near a widow and perhaps there is some leakage or tracking via
the frame through to the brickwork?

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On 26 Feb, 21:51, Harry Bloomfield
wrote:

The rough areas are where the paint is flaking off.
Not in big blisters - just very small rough bits.



It's almost certainly caused by sealing the walls with PVA. New
plaster should be
sealed with diluted emulsion paint.

Nodge wrote:
I have a strange problem with some emulsion painted walls. Must be 6
or 7 years ago since I decorated the hall & landing. I put up a dado
rail and painted above the rail a light green and below a slightly
darker green. I'm pretty sure that I sealed the walls first with some
dilute pva. About a year ago we first noticed some rough patches
appearing in the light green upstairs on the landing. Since then it's
just got progressively worse. But it's only the light green above the
dado rail and it's only upstairs on the landing. Everything is fine
down in the hall, and the darker green below the dado rail is ok up
on the landing. The rough areas are where the paint is flaking off.
Not in big blisters - just very small rough bits.
I've never come across this before and I don't know what's causing
it. I don't think it was my preparation as the paint everywhere else
is fine. But if it's the paint, why isn't it happening all over - not
just upstairs? The walls are all internal walls so it's not damp from
the outside or anything. The problem is what to do about it. If I
just sand the bits that are flaking and repaint I'm worried that the
old paint is just going to carry on flaking. I get the feeling that I
need to get all the old emulsion off the walls and start with bare
walls again.. Would this be the best thing to do and how would I go
about it?
TIA
John

Considering it's been on for 7 years, it's not doing too bad.

Without seeing it, I'd say it's peeling due to shrinkage - even though your
house looks stable and the walls solid, they are in a constant state of
flux, moving slightly with hot and cold cycles, and also humid and dry
periods all take their toll, what started out as minor imperfections,
invisible to the naked eye, have now given way to flaky paint.

Why it's happened only upstairs I don't know - perhaps it's the heat
accumulating on the landing.

--
Phil L
RSRL Tipster Of The Year 2008

Nodge wrote:
I have a strange problem with some emulsion painted walls. Must be 6 or 7
years ago since I decorated the hall & landing. I put up a dado rail and
painted above the rail a light green and below a slightly darker green. I'm
pretty sure that I sealed the walls first with some dilute pva. About a year
ago we first noticed some rough patches appearing in the light green
upstairs on the landing. Since then it's just got progressively worse. But
it's only the light green above the dado rail and it's only upstairs on the
landing. Everything is fine down in the hall, and the darker green below the
dado rail is ok up on the landing. The rough areas are where the paint is
flaking off. Not in big blisters - just very small rough bits.

I've never come across this before and I don't know what's causing it. I
don't think it was my preparation as the paint everywhere else is fine. But
if it's the paint, why isn't it happening all over - not just upstairs? The
walls are all internal walls so it's not damp from the outside or anything.
The problem is what to do about it. If I just sand the bits that are flaking
and repaint I'm worried that the old paint is just going to carry on
flaking. I get the feeling that I need to get all the old emulsion off the
walls and start with bare walls again.. Would this be the best thing to do
and how would I go about it?

TIA
John

Sounds like the glue component failing. I'm going to try adding a
little linseed oil to water based paint for damp situations, might
help it last longer. Spirit based may do better.

If you dont wet porous walls before painting, the wall sucks liquid
out of the paint when applied.


NT

Nodge wrote:
I have a strange problem with some emulsion painted walls. Must be 6 or 7
years ago since I decorated the hall & landing. I put up a dado rail and
painted above the rail a light green and below a slightly darker green. I'm
pretty sure that I sealed the walls first with some dilute pva. About a year
ago we first noticed some rough patches appearing in the light green
upstairs on the landing. Since then it's just got progressively worse. But
it's only the light green above the dado rail and it's only upstairs on the
landing. Everything is fine down in the hall, and the darker green below the
dado rail is ok up on the landing. The rough areas are where the paint is
flaking off. Not in big blisters - just very small rough bits.

I've never come across this before and I don't know what's causing it. I
don't think it was my preparation as the paint everywhere else is fine. But
if it's the paint, why isn't it happening all over - not just upstairs? The
walls are all internal walls so it's not damp from the outside or anything.
The problem is what to do about it. If I just sand the bits that are flaking
and repaint I'm worried that the old paint is just going to carry on
flaking. I get the feeling that I need to get all the old emulsion off the
walls and start with bare walls again.. Would this be the best thing to do
and how would I go about it?

TIA
John



It's unlikely to the pva, emulsion paint being entirely compatible with
it. Whatever's causing it, oil based undercoat usually stabilises
difficult surfaces, and is much more damp resistant. You can apply it
over the existing emulsion after a rub down with coarse abrasive. The
fumes can be a major problem when you're covering a large area though. I
wouldn't want to sleep in the house that night.

mr fuxit wrote:
On 26 Feb, 21:51, Harry Bloomfield
wrote:
The rough areas are where the paint is flaking off.
Not in big blisters - just very small rough bits.



It's almost certainly caused by sealing the walls with PVA. New
plaster should be
sealed with diluted emulsion paint.

The only issue with pva under emulsion is that the colour can be paler
and show brushmarks if the seal is too complete. Nothing that would
cause flaking

wrote:
Nodge wrote:
I have a strange problem with some emulsion painted walls. Must be 6 or 7
years ago since I decorated the hall & landing. I put up a dado rail and
painted above the rail a light green and below a slightly darker green. I'm
pretty sure that I sealed the walls first with some dilute pva. About a year
ago we first noticed some rough patches appearing in the light green
upstairs on the landing. Since then it's just got progressively worse. But
it's only the light green above the dado rail and it's only upstairs on the
landing. Everything is fine down in the hall, and the darker green below the
dado rail is ok up on the landing. The rough areas are where the paint is
flaking off. Not in big blisters - just very small rough bits.

I've never come across this before and I don't know what's causing it. I
don't think it was my preparation as the paint everywhere else is fine. But
if it's the paint, why isn't it happening all over - not just upstairs? The
walls are all internal walls so it's not damp from the outside or anything.
The problem is what to do about it. If I just sand the bits that are flaking
and repaint I'm worried that the old paint is just going to carry on
flaking. I get the feeling that I need to get all the old emulsion off the
walls and start with bare walls again.. Would this be the best thing to do
and how would I go about it?

TIA
John

Sounds like the glue component failing. I'm going to try adding a
little linseed oil to water based paint for damp situations

I don't think that's a worthwhile experiment. You can guess what happens
to oil in water, and a mess is the most likely end result.


, might
help it last longer. Spirit based may do better.

If you dont wet porous walls before painting, the wall sucks liquid
out of the paint when applied.

You need to (relatively) seal porous walls to prevent that. Dilute pva
prevents excessive glugging of moisture but is nowhere near a total seal

Stuart Noble wrote:
wrote:
Nodge wrote:

I have a strange problem with some emulsion painted walls. Must be 6 or 7
years ago since I decorated the hall & landing. I put up a dado rail and
painted above the rail a light green and below a slightly darker green. I'm
pretty sure that I sealed the walls first with some dilute pva. About a year
ago we first noticed some rough patches appearing in the light green
upstairs on the landing. Since then it's just got progressively worse. But
it's only the light green above the dado rail and it's only upstairs on the
landing. Everything is fine down in the hall, and the darker green below the
dado rail is ok up on the landing. The rough areas are where the paint is
flaking off. Not in big blisters - just very small rough bits.

I've never come across this before and I don't know what's causing it. I
don't think it was my preparation as the paint everywhere else is fine. But
if it's the paint, why isn't it happening all over - not just upstairs? The
walls are all internal walls so it's not damp from the outside or anything.
The problem is what to do about it. If I just sand the bits that are flaking
and repaint I'm worried that the old paint is just going to carry on
flaking. I get the feeling that I need to get all the old emulsion off the
walls and start with bare walls again.. Would this be the best thing to do
and how would I go about it?

TIA
John

Sounds like the glue component failing. I'm going to try adding a
little linseed oil to water based paint for damp situations

I don't think that's a worthwhile experiment. You can guess what happens
to oil in water, and a mess is the most likely end result.

Adding linseed to water based paints has been done since long before
emulsion came along. No need to guess.


, might
help it last longer. Spirit based may do better.

If you dont wet porous walls before painting, the wall sucks liquid
out of the paint when applied.

You need to (relatively) seal porous walls to prevent that.

No, its just one way, and not the best option for a couple of reasons.


Dilute pva
prevents excessive glugging of moisture but is nowhere near a total seal


It's unlikely to the pva, emulsion paint being entirely compatible with
it.

Not entirely, painting walls with pva first has caused several people
problems.


Whatever's causing it, oil based undercoat usually stabilises
difficult surfaces, and is much more damp resistant.

Yes, on both counts, but since its likely to be a damp wall problem
this would not be the wisest move.

You can apply it
over the existing emulsion after a rub down with coarse abrasive.

coarse? I wouldnt.

The
fumes can be a major problem when you're covering a large area though. I
wouldn't want to sleep in the house that night.

or the next night. Or the next


NT

Adding linseed to water based paints has been done since long before
emulsion came along.

Whatever for? In that case you might as well mix oil paint with
emulsion. Don't let chemistry get in the way.

Thanks for all the comments.

Having given this some more thought I think it is probably a damp related
problem. We are in the habit of hanging washing over the banisters on the
landing to dry. There's a big radiator downstairs in the hall and the heat
rises upstairs to the landing. Just for some reason the light green emulsion
is affected where the darker green emulsion isn't. Think I'll just sand the
wall down all over and paint again with a good quality emulsion and see what
happens.

John

Stuart Noble wrote:
NT wrote:

Adding linseed to water based paints has been done since long before
emulsion came along.

Whatever for?

to increase the range of substrates the paint will stick to

Don't let chemistry get in the way.


NT