We have damp on our bathroom wall which we only discovered when we removed wallpaper, re-plastered and redecorated.

Our first thought was that we hadn't let the plaster dry for long enough or that the new paint was absorbing moisture from the steam, but then we noticed it was worse after it rained (and, boy, did it rain in late winter/spring).

We've had two roofers check our tiles and a builder look at the wall. The roofers found nothing wrong and the builder suggested that the double-skin bricks in our 1920s house had no cavity above ground-floor level because of a recess for pebble dashing.

I've just been out to look at what happens in heavy rain (getting soaked in the process) and noticed the lie of the tiles, with the lowest tile being at a less sharp angle to the others, leaving a line just above the brick plinth. See picture at http://twitpic.com/e83zlm

There was a drip coming from this line but I wonder whether this is also trickling water into the wall. The main area of damp is about 2-3ft away from the plinth, although there is a small area of damp at the very top of the plinth on the inside.

My theory now is that the water is trickling in but because the plinth is double-skin with cavity, the water is seeping into the wall nearby. I know that with flat roofs the damp can often be feet away from the leak.

Any views on this idea, please, and any ideas on how to remedy this?

Will

On 13/07/2014 12:45, William Bramhill wrote:
We have damp on our bathroom wall which we only discovered when we
removed wallpaper, re-plastered and redecorated.

Our first thought was that we hadn't let the plaster dry for long
enough or that the new paint was absorbing moisture from the steam,
but then we noticed it was worse after it rained (and, boy, did it
rain in late winter/spring).

We've had two roofers check our tiles and a builder look at the wall.
The roofers found nothing wrong and the builder suggested that the
double-skin bricks in our 1920s house had no cavity above
ground-floor level because of a recess for pebble dashing.

I've just been out to look at what happens in heavy rain (getting
soaked in the process) and noticed the lie of the tiles, with the
lowest tile being at a less sharp angle to the others, leaving a line
just above the brick plinth. See picture at
http://twitpic.com/e83zlm

There was a drip coming from this line but I wonder whether this is
also trickling water into the wall. The main area of damp is about
2-3ft away from the plinth, although there is a small area of damp at
the very top of the plinth on the inside.

My theory now is that the water is trickling in but because the
plinth is double-skin with cavity, the water is seeping into the wall
nearby. I know that with flat roofs the damp can often be feet away
from the leak.

Any views on this idea, please, and any ideas on how to remedy this?

Will


I'm guessing the wall faces the prevailing weather (S/SW). It was normal
round here to pebbledash that aspect but IME it was not always done
properly so that patches were "live" from the outset. A hairline crack
is enough to allow a lot of rainwater in which then becomes trapped
behind the render and appears indoors *somewhere* on the internal wall.
By tapping with a screwdriver handle the bad bits will sound hollow.

Since your damp coincides with rainfall, I imagine we can discount the
theory that you are running a laundry or engaging in other high humidity
activities :-)

On Sun, 13 Jul 2014 04:45:22 -0700 (PDT), William Bramhill wrote:

I've just been out to look at what happens in heavy rain (getting soaked in the process) and noticed the lie of the tiles, with the lowest tile being at a less sharp angle to the others, leaving a line just above the brick plinth. See picture at http://twitpic.com/e83zlm

Can't see the pitch of the roof, but a GF's bungalow had quite a shallow
pitch, a cracked tile let in a trickle of water, at the shallower bit the
felt underneath had gradually sagged a bit under the weight until a pool
formed and had then degraded to the point of leaking.
I used silicone sealant to glue the tile together until we could get a new
one, but she sold the place before the tuit landed.

There was a drip coming from this line but I wonder whether this is also trickling water into the wall. The main area of damp is about 2-3ft away from the plinth, although there is a small area of damp at the very top of the plinth on the inside.

Well, in the GF's case I noticed a trickle from a 13A socket. Knowing that
electricity and water mix distressingly well...!
The leak was directly above the socket, so I was lucky there.
--
Peter.
The gods will stay away
whilst religions hold sway

Dear Phil, Stuart and Peter

Many thanks for getting back to me so quickly. I hadn't considered a hairline crack in a tile.

Here are more pictures of the side of the house, with the bathroom being nearest to the camera on the first floor.

There are also three shots of the damp on the inside, with the blank wall being the worst affected but the window wall is also showing signs after today's heavy rain.

http://twitpic.com/e84x0m
http://twitpic.com/e84x1s
http://twitpic.com/e84x2q
http://twitpic.com/e84x48
http://twitpic.com/e84x61

Regards

Will

In message , stuart noble
writes
On 13/07/2014 12:45, William Bramhill wrote:
We have damp on our bathroom wall which we only discovered when we
removed wallpaper, re-plastered and redecorated.

Our first thought was that we hadn't let the plaster dry for long
enough or that the new paint was absorbing moisture from the steam,
but then we noticed it was worse after it rained (and, boy, did it
rain in late winter/spring).

We've had two roofers check our tiles and a builder look at the wall.
The roofers found nothing wrong and the builder suggested that the
double-skin bricks in our 1920s house had no cavity above
ground-floor level because of a recess for pebble dashing.

I've just been out to look at what happens in heavy rain (getting
soaked in the process) and noticed the lie of the tiles, with the
lowest tile being at a less sharp angle to the others, leaving a line
just above the brick plinth. See picture at
http://twitpic.com/e83zlm

There was a drip coming from this line but I wonder whether this is
also trickling water into the wall. The main area of damp is about
2-3ft away from the plinth, although there is a small area of damp at
the very top of the plinth on the inside.

My theory now is that the water is trickling in but because the
plinth is double-skin with cavity, the water is seeping into the wall
nearby. I know that with flat roofs the damp can often be feet away
from the leak.

Any views on this idea, please, and any ideas on how to remedy this?

Will


I'm guessing the wall faces the prevailing weather (S/SW). It was
normal round here to pebbledash that aspect but IME it was not always
done properly so that patches were "live" from the outset. A hairline
crack is enough to allow a lot of rainwater in which then becomes
trapped behind the render and appears indoors *somewhere* on the
internal wall. By tapping with a screwdriver handle the bad bits will
sound hollow.

Since your damp coincides with rainfall, I imagine we can discount the
theory that you are running a laundry or engaging in other high
humidity activities :-)

Condensation and subsequent mould in my wife's flat did not have the
appearance of the internal photo. Either lateral penetration as said
above or water finding a route through the roof tiles and puddling where
the roofing felt lifts over the gutter board and thence into the end
wall internal brickwork.

And, totally off topic... noting your CV from the photo site, can you
kindly arrange for the Sunday Times Review compositor to shift the
sudoku puzzles slightly higher such that the paper fold does not
interfere with the bottom line? Many thanks:-)

--
Tim Lamb

Noted, Tim. Will speak to the puzzles guy tomorrow!

In message ,
William Bramhill writes
Noted, Tim. Will speak to the puzzles guy tomorrow!

Excellent.

I have been meaning to write but, somehow, it did not seem appropriate
to whinge on the letters page.

--
Tim Lamb