Attic Room - Damp patches after re-roof, please help!

[richardbell81]

Hi all,

We moved into a victorian mid terrace house a couple of years ago and had some damp patches appearing in the attic bedroom around the chimney breast areas at each side of the room. After getting the roof patched up here and there we finally decided to bite the bullet and get a complete re-roof to stop the damp issue in the top room as it was beginning to look a real mess. A few months after the roof was done, I decided to remove all the blown plaster so we could get it re-plastered. However when I removed the plaster the bricks underneath still looked really damp and whenever it rains, the patch appears to get worse which suggest to me that there is still a problem somewhere. As we've had all the slates replaced, along with new soakers, lead flashing etc, I wasn't expecting to find this. That particuar stack has been capped off and is not in use but it doesn't look to me like a venting issue, especially as it gets worse when it rains. Although it is a mid terraced house, the adjoining house is 4/5 courses lower as we live on a hill, can't see that has anything to do with it either.

My only idea is to get the external stack completely re-pointed but i'm clutching at straws really.

I have attached a picture and if anyone has any ideas or suggestions as to what could be causing the issue then i'd really appreciate some constructive help and advice.

Thanks in advance,
Rich

 

[ree]

Maybe post pics showing the roof lines on either side of the house by the chimney stacks?

Why not also show angled pics showing where your roof elevations meet the neighbours - at the higher end neighbour's, and the lower end neighbour's?

 

[richardbell81]

Maybe post pics showing the roof lines on either side of the house by the chimney stacks?

Why not also show angled pics showing where your roof elevations meet the neighbours - at the higher end neighbour's, and the lower end neighbour's?

Thanks for the response, I can't get any pics now as it's dark although the other side of the house is not an issue. The problem is just at the side where the neighbours house sits 4/5 courses lower. This may not have anything to do with the problem, I was just mentioning it so you know what's on the other side of the wall.

Here's a pic before the re-roof was done which shows the stack where the issue is.

Rear Stack

• richardbell81
• 19 Feb 2013
• 2

My house on the left. Flashing recently been done.

There is another identical stack at the front of property shown in the album although there is no real issue with this one, but it shows how the houses stand next to one another.

Front stack - outside

• richardbell81
• 19 Feb 2013
• 2

My house is on the left. Roof, flashing, ridge tiles recently done.

 

[tony1851]

It's the leadwork behind the stack which is the problem.

 

[ree]

You said that you had: "some damp patches ... appearing at the c/breast areas at each side of the room". That sure sounds like the other elevation and c/breast?

What do you mean by "no real issue" - there is either a damp issue or there isn't?

Abutments in stepped roofs are often of vital significance as sources of penetrating damp. So is correct venting.

New work is no guarantee of good work.

 

[richardbell81]

It's the leadwork behind the stack which is the problem.

Hi Tony, I thought this also so I checked it and it looks fine. All new lead work, re-pointed, doesn't look like this is the cause of the problem. Could water be getting in further up the stack and channeling down? Makes no sense.

 

[richardbell81]

You said that you had: "some damp patches ... appearing at the c/breast areas at each side of the room". That sure sounds like the other elevation and c/breast?

What do you mean by "no real issue" - there is either a damp issue or there isn't?

Abutments in stepped roofs are often of vital significance as sources of penetrating damp. So is correct venting.

New work is no guarantee of good work.

Yes, damp patches were appearing on both stacks at that end of the room. There is one stack at the front and one at the rear... the other side of the room (i.e. the side attached to the other neighbours house) is fine. The damp patch at the front of the property appeared to be cured after the re-roof but the one at the rear does not seem to have been. I agree correct venting is vital, but with the best will in the world, that doesn't look like a venting problem to me.

 

[tony1851]

'New leadwork' doesn't mean to say it's been done properly.

Weather-proofing chimney stacks is a difficult job at the best of times, and the chimney-roof junction on the upper face is a common weak spot.

Personally I still believe that wetting pattern shows all the hallmarks of a fault behind the stack.

 

[catlad]

Can you not open the skylight and take a few pictures of the lead work behind the chimney stack.

 

[richardbell81]

Can you not open the skylight and take a few pictures of the lead work behind the chimney stack.

Hi Catlad, thanks for response and sorry for the late reply, only just got chance to take the pics. Here's some pictures of the guttering behind the stack and another pic of the internal chimney after heavy rainfall

Untitled

• richardbell81
• 14 Nov 2014
• 1

Untitled

• richardbell81
• 14 Nov 2014
• 1

Untitled

• richardbell81
• 14 Nov 2014
• 1

 

[terrypin]

The bond behind the chimney is wrong for starters.

 

[richardbell81]

The bond behind the chimney is wrong for starters.

what does that mean exactly?

 

[terrypin]

If you look at the last row of slates behind the chimney there's a small strip of slate showing, the first and last rows of slate require a double row of slate to maintain their effectiveness. The bond has been broken, you have two joints, directly in line with each other

 

[richardbell81]

If you look at the last row of slates behind the chimney there's a small strip of slate showing, the first and last rows of slate require a double row of slate to maintain their effectiveness. The bond has been broken, you have two joints, directly in line with each other

Does that not count as a double row? I think the strip of slate showing is a larger 'double width' slate if that makes sense.

 

[terrypin]

The bond has been broken, the slates are in line, it is wrong.