DAMP IN FIRST FLOOR BEDROOM

[professorhinky]

Hi

I have a end of terrace property, constructed approximately 30 years ago, with a truss roof, and interlocking concrete tiles. The gable wall is topped with concrete coping stones, there is a lead flashing from the end gable to the roof, and another (drip) flashing which projects from the gable (side facing the roof) and stops any water dripping off the coping running down the face of the gable and behind the flashing.

A damp patch appeared in my daughters bedroom at the base of the roof on the inner face of the gable and in our room (same place)

So far we have:

1. Stripped the coping stones and relaid them.
2. Formed a lead flashing underneath the bottom three coping stones.
3. Checked the cavity for anyhting (mortar etc) bridging the cavity.
4. Replaced the drip flashing which had deteriated over the years with lead.
5. Re-visited the coping stones and re-cemented the cracks that had appeared due dry weather.

For a while theere has been no problems

Butt this morning after a night of heavy rain we had damp patches in both rooms.

Any ideas?????

 

[professorhinky]

Please help me, this is getting worssee. In the loft you can see several damp patches under teh tiles on the blockwork and lower around the mortar joints.

Could it be that the coping stones are porus?

 

[professorhinky]

I attach Pictures

No.1 is the damp in the back bedroom.

http://i127.photobucket.com/albums/p131/professorhinky/DSCF0005.jpg

No. 2 is the damp in the loft above the bedroom.

http://i127.photobucket.com/albums/p131/professorhinky/DSCF0006.jpg

No.3 is the end gable.

http://i127.photobucket.com/albums/p131/professorhinky/DSCF0003.jpg

4 & 5 are external shots taken in the rain.

http://i127.photobucket.com/albums/p131/professorhinky/DSCF0002.jpg

http://i127.photobucket.com/albums/p131/professorhinky/DSCF0001.jpg

 

[Softus]

I haven't quite grasped what you've got there (a photo would help), but is the section gable that's above the roof line a single or a double skin?

And is it that you believe that porous coping stones would allow water to run inside the wall and into the house? I ask because it sounds as though you have enough flashing to prevent water running down the outside.

Have you checked the relevant tiles for cracking that could be letting water through?

 

[professorhinky]

I've put dome links to the pictures in my last post.

It's double skin above the roof line.

I think it might be the coping as I can't find anything else.

My friend is a roofer and he has checked everything.

 

[Softus]

Good photos. It seems that you were prepared.

Looking inside the loft, the damp seems to start at or above the top of the fifth course of blockwork (above wall plate height), and run down the gable under the coping stones. The lead flashing (as much as can be seen in the photos) looks in good shape, so I can't see any way for water to get under the lead or the tiles.

However, looking outside, the mortar joint between coping stones 6 & 7 looks different to the rest. I'm a bit surprised that you had to remake the mortar joints.

How many coping stones did you strip and relay?

How far is the lead lapped under the coping stones?

Have you checked for water ingress at the ridge?

 

[professorhinky]

There is also damp higher in the loft, but the camera battery went.

All the coping stones were stripped and re-laid.

All the joints between the copings have been done, twice.

Do you mean the lead "drip" flashing or the extra lead we put under the last copings?

 

[professorhinky]

There is no evidence internally of water ingress at the ridge and the builder checked th ridge whilst he was there.

 

[Softus]

There is also damp higher in the loft, but the camera battery went.

How high?

All the coping stones were stripped and re-laid.

All the joints between the copings have been done, twice.

That's the thing - why would they need doing twice if they were solid? I'm concerned by this.

Do you mean the lead "drip" flashing or the extra lead we put under the last copings?

I meant the drip flashing, but what do you mean by the "last" copings? Surely not the lowest ones? I say that because if the water is getting in at a high level then the lowest copings should be taken off the suspect list and allowed to go home.

 

[professorhinky]

There is damp approximately 3/4 of the way up.

Thye were done when they were re-laid, but had slipped slightly, so they were re-done (by someone else, the current guy) later. The reason I was given was that the original builder had done them from top down, rather than bottom up. The bottom stone is fixed with a bolt to make sure.

We leaded under the bottom stones because originally there was no evidence of the damp higher up. I don;t know how far thee lead goes under the copigs, but the builder is a good guy so I'm sure far enough.

The bizarre thing is that we also get this problem at the front of the house, in the same place, but there is no evidence in the loft.

 

[Softus]

Well, wour builder might be a good bloke but his integrity isn't what keeps the roof weatherproof. We all make mistakes.

I'd get up there on a dry day, with a hosepipe, and with an assistant in the loft on the other end of a pair of walkie talkies, and remove coping stones from the top going down until I found the gap.

 

[noseall]

there is a possibility that water can find its way in under the lead soakers as the tiles are flat and not at all profiled. i would be inclined to direct a hosepipe here first.

 

[Softus]

Good point noseall. It's kind of obvious now you've pointed it out.

professorhinky - what seals the inner surface of the gable against water that gets under the abutting tiles?

Has the roofing felt been brought up under the lead flashing?

 

[masona]

there is a possibility that water can find its way in under the lead soakers as the tiles are flat and not at all profiled. i would be inclined to direct a hosepipe here first.

The lead on the tiles does look too thin (wrong code?) I went to one client with the same problem and changed the lead thickness (can't remember the code number) as I have seem them lifted in wind therefore rain getting in, since I have changed the lead, the client never has a problem since. I think the cheapest way is to run a sealant under the lead edge and see how it goes

 

[noseall]

it is wise to incorporate a secondary soaker below the tiles in this case, shaping the soaker with a 'lip' to prevent water trickling into the roof space.

soakers on a plain tile roof are fixed below the tiles with a stepped cover flashing above.