Hi,

I have been having a few problems with damp in my house. I have posted
before about this but have come up with some more info (different) so I
thought I'd post new. I have read some other posting on this but could
not find an answer

I Live in an end of terrace which I bought only a while ago. There is
an alleyway one side of my house - hence end terrace. When I had the
house surveyed, I was told there was damp on the end terrace wall (the
one on the side of the alleyway). I was told this was due to the floor
level of the alley way bridging the dpc. Solution from him was to lower
the floor level of the alleyway to 2 brick lines below the dpc. I
originally posted about this is and the generally opinon was that the
floor level was too high and I needed to lower it.

Another solution offered was to use a disc cutter and cut out a channel
6 inches away from the wall, along the full length of the wall and dig
down to the correct level. Create soak away and filling the channel
with gravel.

I have spoke to a few builders about this and from them I have
discovered sometihng else.

The whole wall externally is painted black (all the way to the chimney
stack). I originally thought this was just exterior paint
(weatherproofing), however one builder told me that it looks like
bitumen paint. He says it may have been put there to prevent damp
getting in, but in reality perhaps it should not be there as by default
it also prevents the wall from breathing and could be the cause of damp
problems internally. So here are my questions:

How can I tell its bitumen paint

Is he right in saying that it may be causing problems. Could it be
causing the damp I am getting on the ground floor (ie on the internal
walls I see bubbling of the plaster, loose bits flaking off and small
bits of black mould in the corners. I also have some mould appearing
in one of the bedrooms upstairs on the inside of the same wall)

Shoud I remove it, and if so how?

Once removed do I need to do anything to the newly exposed wall
(pointing, coating with something else etc)

I will not be doing the work my self, but want to get an idea of what
could be the cause of my damp problems before I get anyone to start any
work

Many thanks

Bhupesh

bp wrote:

The whole wall externally is painted black (all the way to the chimney
stack). I originally thought this was just exterior paint
(weatherproofing), however one builder told me that it looks like
bitumen paint. He says it may have been put there to prevent damp
getting in, but in reality perhaps it should not be there as by default
it also prevents the wall from breathing and could be the cause of damp
problems internally. So here are my questions:

How can I tell its bitumen paint

Wipe it with kitchen roll soaked in white spirit. Bitumen is brown in
solution although it looks black in a solid form. I can't imagine anyone
would choose black to paint a wall.
Whatever it is, it sounds like it should come off and the procedure
would be the same. If it's on the bricks, paint stripper (probably 25
litres plus). If the wall is rendered, might be easier to chop the
render off.
I don't envy you. It's going to be an expensive job and I think I might
look for obvious places where the coating has failed before committing
myself to drastic measures. You might be able to patch those areas with
something similar.
There are 2 basic approaches to this. One that the coating is
impermeable enough to prevent moist air getting out. The other (and much
more likely IME) that it's leaking and allowing water in. Observation in
different weather conditions might give you a clue.

On 28 Jul 2006 08:44:05 -0700, "bp" wrote:


Is he right in saying that it may be causing problems. Could it be
causing the damp I am getting on the ground floor (ie on the internal
walls I see bubbling of the plaster, loose bits flaking off and small
bits of black mould in the corners. I also have some mould appearing
in one of the bedrooms upstairs on the inside of the same wall)

Has the house been fitted with new windows (double glazing)?

--
Peter Parry.
http://www.wpp.ltd.uk/

HI,

Thanks for the replies.

Yes there is double glazing. I did think that there was a ventilation
problem. The previous owner has fittied a vent (air brick) at the
front room. It is high up - near the celing.

Also I checked the air bricks. Most were blocked. I have cleared
them. There are 2 along the black wall (i.e. along the alleyway).
However since the floor level is higher then the air bricks, someone
has created an opening to allow the air to flow. There was alot of
dirt etc in there which was blocking them. I have opened them now, bt
I guess I will have t wait and see if things get any worse. If not I
guess blocked vents were to blame.

About the removal of the paint, could I sandblast it off? Or is paint
stripper the best option.

Thanks

Peter Parry wrote:

On 28 Jul 2006 08:44:05 -0700, "bp" wrote:


Is he right in saying that it may be causing problems. Could it be
causing the damp I am getting on the ground floor (ie on the internal
walls I see bubbling of the plaster, loose bits flaking off and small
bits of black mould in the corners. I also have some mould appearing
in one of the bedrooms upstairs on the inside of the same wall)

Has the house been fitted with new windows (double glazing)?

--
Peter Parry.
http://www.wpp.ltd.uk/

bp wrote:
HI,

Thanks for the replies.

Yes there is double glazing. I did think that there was a ventilation
problem. The previous owner has fittied a vent (air brick) at the
front room. It is high up - near the celing.

Also I checked the air bricks. Most were blocked. I have cleared
them. There are 2 along the black wall (i.e. along the alleyway).
However since the floor level is higher then the air bricks, someone
has created an opening to allow the air to flow. There was alot of
dirt etc in there which was blocking them. I have opened them now, bt
I guess I will have t wait and see if things get any worse. If not I
guess blocked vents were to blame.

About the removal of the paint, could I sandblast it off? Or is paint
stripper the best option.

I doubt if you could blast bitumen. Too rubbery.
I wouldn't pin all your hopes on the ventilation issues

On 31 Jul 2006 10:00:43 -0700, "bp" wrote:

Yes there is double glazing. I did think that there was a ventilation
problem. The previous owner has fittied a vent (air brick) at the
front room. It is high up - near the celing.

The pattern you are describing of mould on corners and upstairs is
very suggestive of condensation. I'd be inclined to concentrate on
proper heating, ventilation and possibly insulation of walls where
they are enclosed (within built in wardrobes etc) before trying to
remove the paint on the outside.

Also before going foe expensive solutions look at the simple standard
things of clearing all rubbish and plants away from the outside wall
and creating a gravel French Ditch around the sides.

About the removal of the paint, could I sandblast it off? Or is paint
stripper the best option.

If it gets to that look at employing a commercial sandblasting
company - with domestic equipment it will take you ages and is
unlikely to work well. I'd try the simpler bits for a year first.
--
Peter Parry.
http://www.wpp.ltd.uk/