I have recently moved into a new home and have no past experience of
all this stuff. The home buyers valuation noted that i had penetrating
damp due to the rendering on the exterier walls being porous. This has
led to the internal walls in the upstairs bathroom and bedroom being
damp. The advice was to strip back all the render and replace with new
mix and non porous sand and cement layer. Its quite a costly job and i
just wondered whether it would be possible just to simply paint the
exterior with a non porous paint. Or is it too late will the damp then
remain trapped in the bricks and rendor or will it dry out in time? I
guess i was just lloking for a cheeper option any ideas?

wrote:
I have recently moved into a new home and have no past experience of
all this stuff. The home buyers valuation noted that i had penetrating
damp due to the rendering on the exterier walls being porous. This has
led to the internal walls in the upstairs bathroom and bedroom being
damp. The advice was to strip back all the render and replace with new
mix and non porous sand and cement layer. Its quite a costly job and
i just wondered whether it would be possible just to simply paint the
exterior with a non porous paint. Or is it too late will the damp then
remain trapped in the bricks and rendor or will it dry out in time? I
guess i was just lloking for a cheeper option any ideas?

At the risk of sounding obnoxious, your valuer is talking ********, no
amount of porosity will cause damp in a wall, if the rendering was not there
at all, the bricks would not allow damp to get across to the inner leaf, the
only reason they are is because the rendering has come away from the
brickwork and this gap is holding the water, so no, there is no paint on the
market that can help in this situation, only having it re-rendered can stop
it now.

wrote:

I have recently moved into a new home and have no past experience of
all this stuff. The home buyers valuation noted that i had penetrating
damp due to the rendering on the exterier walls being porous. This has
led to the internal walls in the upstairs bathroom and bedroom being
damp. The advice was to strip back all the render and replace with new
mix and non porous sand and cement layer. Its quite a costly job and i
just wondered whether it would be possible just to simply paint the
exterior with a non porous paint. Or is it too late will the damp then
remain trapped in the bricks and rendor or will it dry out in time? I
guess i was just lloking for a cheeper option any ideas?


This is the result of using cement render that is seen again and again.
Cracks form, water gets in, but it cant evaporate out enough, so the
wall slowly gets wetter and wetter. It it goes on long enough the wall
may get wet enough for freeze thaw cycles to start breaking the brick
faces up. If the unwise owner rewaterproofs, the cycle continues and
further brick deterioration occurs.

The advice youve been given is no use, nor is painting. While these
attempts are popular they are basically counterproductive.

The dampness level in a wall is an equilibrium between water getting in
and damp evaporating out. The only way a wet wall will dry is if you
let it evaporate dry. The best thing is thus to remove render to let it
dry off. Attempts to 'waterproof' walls are precisely what has caused
your present situation, there is never long term sustained
waterproofing, so water ends up getting in, but cant evaporate. Going
with a finish that allows evaporation is the effective solution.

Paint wont help the wall evaporate its damp. Only removing render will
let it dry out. For a refinish, lime render allows evaporation, cement
doesnt, so lime it. Equally avoid evaporation-proof paints such as
masonry paint or pliolite.

Some of this is alien to some here, if you want more explanation of how
this works try
http://www.periodproperty.co.uk/discussion_forum.htm


NT

wrote:

This is the result of using cement render that is seen again and again.
Cracks form, water gets in, but it cant evaporate out enough, so the
wall slowly gets wetter and wetter.

Yeah, yeah, we know the party line but, if you seal the cracks with a
flexible paint, new water will stop getting in, and what's in the wall
will dry out to the inside. If the cracks reform, you'll have to do it
again, but it beats the hell out of hacking off the render. Of course
it's a compromise, but not everybody has thousands to throw at the job.

You still come across as a patronising and pompous little **** by the way.

Stuart Noble wrote:
wrote:

This is the result of using cement render that is seen again and
again. Cracks form, water gets in, but it cant evaporate out enough,
so the wall slowly gets wetter and wetter.

Yeah, yeah, we know the party line but, if you seal the cracks with a
flexible paint, new water will stop getting in, and what's in the wall
will dry out to the inside. If the cracks reform, you'll have to do it
again, but it beats the hell out of hacking off the render. Of course
it's a compromise, but not everybody has thousands to throw at the
job.
You still come across as a patronising and pompous little **** by the
way.

That's a bit rum...Isn't it best just to give advice to anyone who asks and
let them make their own minds up instead of getting argumentative about it
all? - FWIW I don't particularly agree with exterior rendering using
sand/cement neither but when somewhere is already done with it, or someone
wants to know how to do it, I'll just give the advice and let them make up
their own mind.

Stuart Noble wrote:
wrote:

This is the result of using cement render that is seen again and again.
Cracks form, water gets in, but it cant evaporate out enough, so the
wall slowly gets wetter and wetter.

Yeah, yeah, we know the party line but, if you seal the cracks with a
flexible paint, new water will stop getting in, and what's in the wall
will dry out to the inside. If the cracks reform, you'll have to do it
again, but it beats the hell out of hacking off the render. Of course
it's a compromise, but not everybody has thousands to throw at the job.

So you recommend repeating what was done the first time round that got
the wall into this sorry mess, trying to waterproof it.


NT

wrote in message
ups.com...
wrote:

I have recently moved into a new home and have no past experience of
all this stuff.

This is the result of using cement render that is seen again and again.
snip
Cracks form, water gets in,
Some of this is alien to some here, if you want more explanation of how
this works try
http://www.periodproperty.co.uk/discussion_forum.htm

If it were a solid brick/stone wall you would be correct
If it is a cavity wall you are again talking B******S
As the OP did not state the type of construction, you are just jumping to
conclusions and spouting the usual line from your only source of knowledge.
periodproperty.


-

Mark wrote:
wrote in message
ups.com...

This is the result of using cement render that is seen again and again.
snip
Cracks form, water gets in,
Some of this is alien to some here, if you want more explanation of how
this works try
http://www.periodproperty.co.uk/discussion_forum.htm

If it were a solid brick/stone wall you would be correct
If it is a cavity wall you are again talking B******S
As the OP did not state the type of construction, you are just jumping to
conclusions and spouting the usual line from your only source of knowledge.
periodproperty.

Are you saying the same basic principle of water in versus evaporation
out does not apply to cavity walls?


NT

wrote in message
oups.com...

This is the result of using cement render that is seen again and
again.
snip

If it were a solid brick/stone wall you would be correct
If it is a cavity wall you are again talking B******S
As the OP did not state the type of construction, you are just jumping
to
conclusions and spouting the usual line from your only source of
knowledge.
periodproperty.

Are you saying the same basic principle of water in versus evaporation
out does not apply to cavity walls?

Open your eyes and look at how many houses have been built over the last
_100 years_ with a cement render finish.
Your "basic principle of water evaporation" is nonsense when applied to a
cavity wall house.
Too much theory and zero practical knowledge yet again.



-

Mark wrote:
wrote in message

Are you saying the same basic principle of water in versus evaporation
out does not apply to cavity walls?

Open your eyes and look at how many houses have been built over the last
_100 years_ with a cement render finish.
Your "basic principle of water evaporation" is nonsense when applied to a
cavity wall house.
Too much theory and zero practical knowledge yet again.

I am aware not every house has problems, and why. I thought you had
something useful to add.


NT

wrote:
Mark wrote:
wrote in message

Are you saying the same basic principle of water in versus evaporation
out does not apply to cavity walls?

Open your eyes and look at how many houses have been built over the last
_100 years_ with a cement render finish.
Your "basic principle of water evaporation" is nonsense when applied to a
cavity wall house.
Too much theory and zero practical knowledge yet again.

I am aware not every house has problems, and why. I thought you had
something useful to add.


Well: In that he identified that you had not, he had


NT

wrote:
Stuart Noble wrote:
wrote:

This is the result of using cement render that is seen again and again.
Cracks form, water gets in, but it cant evaporate out enough, so the
wall slowly gets wetter and wetter.

Yeah, yeah, we know the party line but, if you seal the cracks with a
flexible paint, new water will stop getting in, and what's in the wall
will dry out to the inside. If the cracks reform, you'll have to do it
again, but it beats the hell out of hacking off the render. Of course
it's a compromise, but not everybody has thousands to throw at the job.

So you recommend repeating what was done the first time round that got
the wall into this sorry mess, trying to waterproof it.


NT


You seem to think it's some kind of carnal sin to stop water ****ing
through your walls. Believe me, pliolite paint does seal cracked render
and the walls do dry out. I had a choice in my own house between £6K to
re-render the wall or 4 cans of paint. 5 years down the line I'm glad I
chose the paint option. If we get a wet winter, I might change my mind

Phil L wrote:
Stuart Noble wrote:
wrote:

This is the result of using cement render that is seen again and
again. Cracks form, water gets in, but it cant evaporate out enough,
so the wall slowly gets wetter and wetter.
Yeah, yeah, we know the party line but, if you seal the cracks with a
flexible paint, new water will stop getting in, and what's in the wall
will dry out to the inside. If the cracks reform, you'll have to do it
again, but it beats the hell out of hacking off the render. Of course
it's a compromise, but not everybody has thousands to throw at the
job.
You still come across as a patronising and pompous little **** by the
way.

That's a bit rum...Isn't it best just to give advice to anyone who asks and
let them make their own minds up instead of getting argumentative about it
all? - FWIW I don't particularly agree with exterior rendering using
sand/cement neither but when somewhere is already done with it, or someone
wants to know how to do it, I'll just give the advice and let them make up
their own mind.



Oh stop being so reasonable :-)

Mark wrote:
wrote in message
oups.com...

This is the result of using cement render that is seen again and
again.
snip

If it were a solid brick/stone wall you would be correct
If it is a cavity wall you are again talking B******S
As the OP did not state the type of construction, you are just
jumping to conclusions and spouting the usual line from your only
source of knowledge. periodproperty.

Are you saying the same basic principle of water in versus
evaporation out does not apply to cavity walls?

Open your eyes and look at how many houses have been built over the
last _100 years_ with a cement render finish.
Your "basic principle of water evaporation" is nonsense when
applied to a cavity wall house.
Too much theory and zero practical knowledge yet again.


He's right in one respect inthat sand/cement sets way too hard and is
therefore susceptible to cracking...this could be because the modern
approach is wrong WRT mixing, it's commonly accepted that 'strong is good'
when the opposite is actually true, the house I am in was built with a mix
of 10 sand, 1 cement and 1 lime....while the pointed surface is porous, the
inner is rock hard, exactly as it needs to be, and the house is 60 years
old.

Stuart Noble wrote:

You seem to think it's some kind of carnal sin to stop water ****ing
through your walls.

not sure why you make such things up


Believe me, pliolite paint does seal cracked render
and the walls do dry out.

I dont. Have used it myself and read far too much to buy it. In many
cases the walls will dry out after such treatment, but also in many
cases it wont. And when it doesnt, quite a bit of damage will ensue. I
dont see that as a decent solution, one worthy of recommendation. But
yes, you could chance it.


NT

Phil L wrote in message
.uk...
Mark wrote:
wrote in message
oups.com...

This is the result of using cement render that is seen again and
again.
snip

If it were a solid brick/stone wall you would be correct
If it is a cavity wall you are again talking B******S

Are you saying the same basic principle of water in versus
evaporation out does not apply to cavity walls?
when
applied to a cavity wall house.
Too much theory and zero practical knowledge yet again.


He's right in one respect inthat sand/cement sets way too hard and is
therefore susceptible to cracking...

All types of external render whatever the ingredients and mix will crack
given sufficient movement, the only thing meow is correct on is if water
gets into a defect in the render and freezes it will lead to more cracks in
the render.
Maintenance of the external surface would prevent this.
The point I was objecting too was the notion that damp remains trapped in
the bricks and render and will not dry out,
in the external cavity wall this would be almost impossible in this country.
This is the very reason why cavity wall construction often with a cement
render was first used in coastal towns a 100 years ago, to keep the damp
out.



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