Roof advice please

[zunetunes]

I'm getting conflicting advice from local roofers, so looking here for some input.

This pic was taken BEFORE any work was done. This side of the house is exposed to the wind and rain of which we have a lot!

We have damp in the wall marked (A). A builder (friend) came and said we needed to get a roofer. The mortar below the tiles at position (B) (all the way down the line of tiles) was very damp and crumbly. Some of the rendering on that wall was cracked and blown too.

So the roofer came and said we needed a 4" overlap so he removed the tiles and relaid them with additional tiles to make a nice overlap. The builder then re-mortared and used sealant to make sure no water crept in between tile and mortar. The roofer also said that the flashing to the slate roof (C) was wrong and so replaced it. That flashing is now exposed so that it's flat against the wall and runs under the slates.

It doesn't seem to have sorted the problem out, but now I have a BIGGER problem.

After they left we started getting serious damp on the inside of the wall where the flashing (D) is (not just at point B but all the way down from the ridge). This flashing was replaced about 8 years ago by the previous owner who used a reputable local roofer. The current roofer came back looked at it, said it was all ok apart from a little bit of flashing they said was missing just the other side of the ridge. They did that. The problem does not seem to have been sorted though. Of course once you've got damp it can be difficult to know if the problem is solved or if it's the damp that was already there, so it's taken a while!

Anyway, we have other major damp problems in the house and are going to get another roofer to sort all the roofs. The first one who came (and this is where I'm looking for advice) - a reputable local roofer - said that the flashing at D is wrong and that as it is tiles instead of slates, the flashing should lay OVER the tiles and that this is probably causing the problems.

So I've got two roofers saying that it is is correct and one (who I'm more inclined to believe) who say it's wrong. Any thoughts?

 

[Feltwell]

Your flashing at D does not need to lay over the tiles, but there is more than one way to skin a cat! With my way, individual lead "soakers" are cut, placed under the tiles, and turned up the wall - then a seperate piece of flashing is mortared into the wall, covering the exposed tops of the soakers. I'll post some pictures up later, it'll make sense then I promise!

In the meantime, can you post some close up pictures of what you have now? Your picture above doesn't really give enough detail.

 

[middi]

I agree with Feltwel, In order to guarantee no leaks from tiles into wall the best and most tidy way is to use overlapping lead soakers for each tile and then an " overstrip" of lead cut and mortared into the wall ovelapping the soakers " ears" down to tile level.

Middi

 

[stuart45]

If you have interlocking tiles the cover flashing should lap over the roof by at least 6 inches on flat tiles and over a full roll at least on a profiled tile.

 

[zunetunes]

Just nipped out and taken a couple of pics as it is now:

Oh and yes I know about that slipped slate!

 

[stuart45]

They look like interlocking tiles to me, in which case the cover flashing goes over the tiles by 6 inches.

 

[Feltwell]

Ahh - yes, they look like interlocking tiles to me as well, in which case I agree with Stuart 45 and also think it's a cover flashing you need (which goes over the tiles) at "D", as does this website:-

http://www.roofconsult.co.uk/articles/tiling/tips29.htm

At first I thought you had plain rather than interlocking tiles from your first picture - plain tiles do use soakers.

There are many different ways of doing it though, I *think* you can use a secret gutter with interlocking tiles, like the below:-

http://www.leadsheetassociation.org.uk/step-and-cover-flashings-and-secret-gutters

Roofers I know tend to avoid them because they are difficult to make and apparently can get clogged.

It looks what you've got there at the moment is soakers and a plain flashing, like the below, which isn't right for your type of tiles.

http://www.leadsheetassociation.org.uk/soakers-and-step-flashings

So it looks to me like your roofer who is telling you that the current flashing you have at "D" is wrong, is right!

 

[eezageeza]

We spent ages (years) struggling with damp in a wall very similar to yours; we did exactly what you're doing and replaced loads of flashing etc ....after years of living with damp walls we finally diagnosed the problem as hairline cracks in the render. So think laterally - it may not be the roof that's the prioblem!

 

[Feltwell]

It's a good point from Eezageeza - fron the look of the modern interlocking roof tiles, UPVC windows and door someone's not been too sympathetic to your old house in the past. Is the render cement based? It does look rather like modern masonry paint in the picture. If so, any water that's getting in will be well & truly trapped.

That flashing has to be a prime suspect though - given that it's the wrong type and doesn't look to have been done too neatly either. Before you rush to replace it, is it a good time to replace those tiles with slate to match the neighbouring roof? It's only a small area.

 

[zunetunes]

Thanks for all your replies - exactly what I was looking for.

Most of what you see in the picture is an extension, possibly late Victorian/early Edwardian. The main building is made of sandstone, with an original concrete render. Yes it's definitley original and it's a very strong mix. It really looks like water comes OUT through the hairline cracks rather than going in which makes me think it's the roof that's the problem. It's the original slate roof to the main building, so no felt and the sarking has mainly fallen away. The slates only just overhang the wall and due to our exposed position the rain could easily get blown back. Also the wooden trim that's been used is pretty rotten and definitely replacing. There's going to be alot of expense with scaffolding etc whatever happens, so I'm thinking we'll get the whole lot done (2nd mortgage here we come)

I'd like to get the roofer back who we had recently and tell him to sort it out, but as he's already said it's done properly I think it could be more trouble than it's worth and maybe we need to write it off to experience!

I've attached another couple of photos if it's of any interest, of the rest of the house. Still waiting for estimate to come in from the roofers - any guesses how much including scaffolding? I think they will reuse exisiting slates and tiles as much as possible.

 

[Feltwell]

Interesting place. What was the shop originally, and are you going to re-open it?

Still waiting for estimate to come in from the roofers - any guesses how much including scaffolding? I think they will reuse exisiting slates and tiles as much as possible.

Full strip and re-roof? Very hard to say. I spent £16k on a complete new roof, including all new tiles, with lots of scaffolding (very tall house). That included 3 conservation rooflights, a new dormer window (to replace an existing rotten one) and getting some new fascia board machined. The roof timbers were in good condition, just 1 rafter end had to be replaced.

Your roof looks smaller than mine, and if the existing slates / tiles are mostly reuseable that will help a lot. I'd take a stab at £8-£10k but it is a guess! Make sure you've got a contingency, final cost depends on what they find once the roof timbers are exposed. Apologies if this is stating the bleedin' obvious, but think about if you want to add any rooflights now - we added 1 new one and it's made a huge difference to the amount of light in one room, our neighbours are cursing not doing the same when they did their roof a few years ago. To go back and add one now would be much more expensive, due primarily to the scaffolding. Adding one whilst the roof is off anyway is quite an easy job.

 

[zunetunes]

It was a general store and no we won't reopen it. There's another general store in the village and the local shops have been closing down over the last two or three decades.
I'm preparing myself for 20k including contingency, but really hoping its less!

 

[Lime]

Many lead installers either omit or don't install soakers correctly.
See the Guide to Good Lead Booklet on this site:

http://metalprocessors.ie/content/Technical-Data-Sheets.html

Flashing as on this thread in severe weather requires 3 separate sections of lead: soakers, step covers and flashing.

 

[Feltwell]

I don't think you're supposed to use soakers at all with modern interlocking tiles Lime - not sure why, but I'd hazard a guess it's because it lifts them slightly and stops them interlocking properly.

Edit - just found this, which says it's due to the lead not being supported properly:-

http://www.britishprecast.org/documents/07sideabutment.pdf

 

[Lime]

Soakers are essential as your link shows (using the underfelt).
A secret gutter is a good idea too but more expensive and prone to blockages if in an area of small leaf/needles/bits fall.

 

[Feltwell]

Soakers are essential as your link shows (using the underfelt).

Erm.....

Lead soakers should never be used with interlocking tiles, as the lead needs to be supported in its length, and with interlocking tiles this will not happen beyond the 75 100mm of headlap

Zunetunes, there's some good stuff on that link - look towards the end of it and there is a specific section on flat interlocking tiles.

 

[Lime]

Effectively what is being said is that modern interlinking tiles cannot be made properly weather tight unless a secret gutter is installed.
The alternative is to fold the underfelt up the wall as shown in the diagram.

 

[zunetunes]

Thanks for all contributions. The main thing I needed to know was whether the current set up is correct. I believe the consesus is that it's not.
I'm guessing we've got a secret gutter only and that it isn't doing the job effectively and is letting water in.