Chimney Flashing Leaking (still) what should be where?

[dhutch]

Ive got a leak around my chimney, which appears to be leaking down the long (sloping) side and off onto the ceilingbelow.

Had the roofer look at it once and I beleve he reseated some loose lead and then attempted to seal the end of felt onto the lead with silicon and expanding foam due to the felt being in his mind to short, preventing him tucking it up under the lead. Sounded like a bit of a bodge at the time but if it held still spring i have other things to think about on the house!

However, its still pouring in! The felt is shot which i know, probebrly origanal to the house (1940's) although the tiles have been replaced more recently.

My understanding is that the felt in the main is there to keep the wind from blowing rain/snow up under the tiles, with the tiles being the first line of defence. How true does this hold around the chimney? Most lead i have seen has the peice along the bottom ending over the tiles, and the peice of lead down the long side ending onto that, and the peice on the top edge starting under the tiles and end on the peice running down the side. Fine. But what stops the rain running of the long edge of the long peice (if your still following) Which obviously is quite long (say, 3-4ft) and not nearly as wide!

This appears to be the issue, as its the first rafter in from the chimney thats sodden, directly under where i would antsipate the flashing ending.

I wasnt at the house when he did the work, as I work 8 till 5 myself and have very limited flexabilty in that. However I have one day booked off on monday to supervise my cavity walls being filled and loft insulated so would like to try and get him to come then to look at it with me and get it fixed for good.

 

[Space cat]

My understanding of how flashing works is that you have multiple pieces of lead bent into L shapes. I think they're called soakers. Think of them as angled tiles, interleaved with the flat tiles and extending up the wall behind the long piece that you can see.

The long piece is set into the mortar joints of the brickwork and overlaps the tops of the soakers so that no water gets down behind them. Meanwhile, any water running across a soaker underneath a tile will roll off onto the tile on the next row down or the soaker two rows down. It's not easy to visualize so you might want to draw it.

Leaks can happen for a number of reasons. If it isn't getting in at the top of the long piece, there might be a split in the angle of a soaker. Alternatively, this --

-- due to the felt being in his mind to short, preventing him tucking it up under the lead.

suggests that there aren't any!

 

[cotswoldbuilders]

Slates or small tiles should have lead soakers under each one, which will over lap the front lead apron on the stack.
A lead flashing is then installed, chased into stack (stepped flashing looks far neater than a straight flashing ) this is dressed down over the soakers.
If you have the larger tiles, the lead would be chased into stack as above, but would be dressed down and over the tiles.

 

[dhutch]

My understanding of how flashing works is that you have multiple pieces of lead bent into L shapes. I think they're called soakers. Think of them as angled tiles, interleaved with the flat tiles and extending up the wall behind the long piece that you can see.

Right ok. Just googled soakers and I have seen them before, makes much more sense than having a single long peice, and as you say, allowed you to intereave them with the tiles. Sorted.

Im at work now (sigh) but google images is just about clear enough to show that I do indeed have single stepped peices of flashing going into the brick, not a solid run. I think I must have seen that on conservatorys and the like, where its cut in across the wall and then sealed to the roof. Presumably because you cant interleave with plastic sheet!

Slates or small tiles should have lead soakers under each one, which will over lap the front lead apron on the stack.
A lead flashing is then installed, chased into stack (stepped flashing looks far neater than a straight flashing ) this is dressed down over the soakers.

So there then should be a separte peice of lead, forming a right angle the other way and interleaving with the tiles? Or is it or could it be all the same peice, with the 'soaker' going into the brickwork?

http://chestofbooks.com/architecture/Building-Construction-3-1/images/Fig-475-Soakers.jpg
http://alwaysgutteringandroofing.co.uk/data/images/chimney_flashing_after.jpg

I would post a image taken from streetview but i dont have a way to upload it at work as they have blocked all uploading sites i know of or can find via google but i can do tonight for completeness.


Daniel

 

[cotswoldbuilders]

The soakers are seperate to the flashings, a soaker is laid fixed to the tile batten, then a tile laid, and continued up.
The soakers are not fixed to the wall but sit over the tile and extend up the wall, usually cut out of 150mm wide lead, bent half way.
The stepped lead flashing is fixed into the wall, and covers the side soakers.

 

[dhutch]

The soakers are seperate to the flashings, a soaker is laid fixed to the tile batten, then a tile laid, and continued up.
The soakers are not fixed to the wall but sit over the tile and extend up the wall, usually cut out of 150mm wide lead, bent half way.
The stepped lead flashing is fixed into the wall, and covers the side soakers.

Yes. Allowing the roof to move relative to the wall am amount, without tearing the lead.

I have a feeling that the previous owner (a builder or sorts) may have replaced the tiles himself, so i suppose it is ulitmatly possable that he simply failed to replace the soakers, or reused them like he reused the valley tiles (the other area that leaked, and was fixed last time the roofer came) hence the leak.


Daniel