Ohh no, not another damp question.......

[Feltwell]

As is so often the case, it's the bits of Feltwell Towers that have been messed about with in the past that are causing problems now.

Our "front" door is actually on the side of the house, in a flat roofed porch structure, original to the house. There are very clear signs of damp inside the porch, at the wall/ceiling junction above the door.

And this is the porch parapet from above:-

The whole top section has been rebuilt in the past, not particularly well. The flat roof inside the stone parapet appears to be OK, the problem I suspect is the terracota projecting string course (can't think of the proper word for it!) which is just below the top stone section.

That course has been re-laid such that the top of it slopes towards the porch - so any rain that falls on it will just puddle at the back and soak into the masonry. You can see that someone has obviously realised this and tried to put a thin fillet of cement mortar on top to give it some slope away from the wall, but that fillet has failed and is loose.

In an ideal world the top section would be re-built, but I don't want to do this for several reasons - time, cost, effort (those stones are going to be seriously heavy!) and as the whole thing has been rebuilt with cement mortar I think I'd cause too much damage taking it apart.

So, my idea was to put lead sheet on top of the terracota string course - lapping up the wall and mortared in beneath the stone top section, and rolling over the front edge of the terracota string course by a very small amount. There would be no slope on this, it would just allow the rainwater to puddle on it and evaporate off. I *was* going to be asking about soldering lead - in order to make something to go round the corners - but then Stuart45 helpfully posted up a reference to "Just Lead" on another topic, a firm I'd never heard of, who look like they pre-fabricate all kinds of lead building items - I think I'd get them to make something up.

http://justlead.co.uk/

Has anyone got any better ideas on how to solve this problem, or can anyone see any flaws in my lead idea above? Aesthetically I think it would be OK - the angle you view it from below, coupled with the projection of the string course, means that you'll hardly see it even where it does lap up the wall.

(And please ignore the grotty coach lamp with the horrendously badly done cable leading to it, yet another job on the list to take that down, it doesn't even work. And the very messy waste pipes and grotty plastic hopper and downpipe. And the windows and door that need painting. And.......... :lol: )

 

[eezageeza]

Corbelling!

I'm not sure about not having a slope on the lead - I'm always happier seeing positive drainage rather than sitting water! You could achieve this with a wooden fillet under the lead sheet - like a feather edged fencing board (tho' perhaps a little heavier duty!).

And i don't think I'd go to the expense of having custom made corners - you'd get a good enough result fitting sheets yourself and sealing with silicon lead sealant.

 

[Feltwell]

Of course - corbel. I had a mental blank on that one!

 

[Penners]

Bleedin' obvious Penners statement number 764: your idea of flashing the top of the terracotta corbelled courses should work - provided you have correctly identified the source of the leak. The problem with a structure like that is the huge number of potential leak points.

However, I do agree with eezageeza that you would do better to try and achieve a fall on the lead, so that water flows off it. However, I'm not so convinced about using a bit of tapered wood, what with wood being liable to rot (tanalising only delays this for a while - doesn't completely eliminate it). I think I would create the fall with a fillet of mortar under the lead.

 

[Lime]

To be frank I don't think that is all original.

 

[Feltwell]

It's been rebuilt but I'm confident it is original. It matches the other half of the house (it's a semi) and matches another near-identical house built by the same builder elsewhere in the town.

 

[Lime]

It's been rebuilt but I'm confident it is original. It matches the other half of the house (it's a semi) and matches another near-identical house built by the same builder elsewhere in the town.

Ok, I was mistaken.
Apart from lead, which I use at the slightest provocation, I'd consider using a lime cement fillet on the existing but cleaned substrate with glazed tiles placed at a slope outwards upon it.
(similar to the old red tiles found in homes about 60 years ago: about ¼" thick )

 

[Feltwell]

Bleedin' obvious Penners statement number 764: your idea of flashing the top of the terracotta corbelled courses should work - provided you have correctly identified the source of the leak. The problem with a structure like that is the huge number of potential leak points.

Very true Mr P. I need to get up there and have a good ferret round again, just to be sure. The top section was rebuilt because the previous owner redid the flat roof I believe. Last time I checked it looked to be OK - the roof felt turns up a fair way behind lead flashing below the top stones on the inside of the parapet, it all looked to be in good order, including the joints. But it does need another check.

Apart from lead, which I use at the slightest provocation, I'd consider using a lime cement fillet on the existing but cleaned substrate with glazed tiles placed at a slope outwards upon it.
(similar to the old red tiles found in homes about 60 years ago: about ¼" thick )

Interesting idea. I can see the point of the mortar, but why the tiles? Is it simply to give a stronger surface? It would be easy enough to do - I presume some cheap modern bathroom tiles would be as good as any.

I'm debating at the moment what to do with my bay window roof on the front of the house as well. It's another flat roof, it was redone in felt by the previous owner about 10 years ago and whilst it doesn't leak, it doesn't have the correct fall. It drains to the rear, to a channel against the wall - which is how it should be, that was how it was built originally. However when it was refelted they left a section around the edge that slopes towards the outside, which now drips water when it rains onto the cill below - which is causing rot in the frame and damp in the bay wall below. I have several choices really:-

1) Re-do the whole thing in lead with a roll on the outside edge to stop any drips. The best solution, but probably expensive - although it's not a big area - and I'm a bit worried about thieving little gits spotting shiny new lead. It's about 12' up but the drainpipe would enable an agile person to get up there.
2) Re-do it in felt with an upstand of some kind on the edge
3) Leave it as is and fix some small guttering to the outside edge - Longbottom foundry do a 3" half round cast iron, about the smallest you can get I think. Could look a bit messy though, it was never designed to have this.

 

[Lime]

I can see the point of the mortar, but why the tiles?

I'm suggesting tiles as a substitute for lead.
The glaze on the tiles would present a waterproof surface off which the rain could run easily.
Also plant/lichen growth would be reduced.

 

[Feltwell]

Is there a speed award anywhere?

A mere 3 and a half years after posting this, I've finally got a lead worker here doing both the porch corbel and the bay roof. That's quick for me, I must need more Kit-Kats. Pictures in due course!

 

[Penners]

Well done, Feltwell. My old granddad used to say "a job rushed is a job ruined", and his principles obviously carry resonance with you.

 

[Feltwell]

Well, the porch leadwork is done, and I'm rather pleased:-







If anyone's interested in how it was done, I'll post up brief details.

Bay window roof to be done next week, judging by the quality of work on the porch it's going to look good! Many thanks to Doug (DJH) for suggesting the leadworker.

So nice to deal with a tradesman who takes as much care over my house as I do, who really knows his stuff, and who - whilst not turning up quite as originally planned due to another job overrunning - did keep me updated on when he would arrive.

 

[DJH]

That's an excellent example of the very best leadwork and shows how even a small job can be carried out neatly and to a high standard. It's how all leadwork should be done.
Please post some details so that we can all learn how it's done and expect the same from other leadworkers... 8)

Glad I could be of help Feltwell.

Doug

 

[malcolm]

Is the use of a stainless drip edge with the lead folded around it a new thing? I had a bay re-leaded on Monday and they used the drip edge as they said it reduced movement. The original was just nailed on.

I let them use the lead sealant on the flashing, but I don't like sealants as they tend to crack. There is room for some render on top when I patch up, but is there a better way of sealing the top of the flashing?

I like the way lead workers think about falls and drips rather than just rely on lead being waterproof.

 

[DJH]

Not really Malcolm, along with strips of copper it's been used for stiffening and securing the free edge of lead sheet for a long time. Stainless steel is more rigid than the readily available quarter hard copper strip and should be used in exposed conditions to help resist wind lift and. of course, to obtain a nice neat profile edge like the one Feltwell has on his porch.

The joint where flashing are mad into the structure has always been a problem for a number of reasons the most common being the lack of depth of the chase cut into the wall (usually done by the builder ) meaning that the minimum width inserted of an inch (25 mm) is difficult to attain and after a while the expansion and contraction of the lead will result in any pointing cracking and falling away. I could bang on about flashing ( ) but I won't bore you...but really in a horizontal or any abutment situation flashing should be fixed under a dampcourse or cavity tray. Some chance in an Historic or period property... 8)

A way of sealing the top of flashings is to apply sealant into the chase first and then point in with mortar to match existing...

Doug

 

[malcolm]

Thanks Doug, I like the stainless strip - seems a more sensible solution than nails which let water into the woodwork and then rust away within 100 years. That's the way we've gone for the sealant - it's in the mortar joints and will be hidden by half an inch of render which should give it double protection. Triple protection if you count the 12 inch roof overhang above. Not that I get paranoid about these things you understand.

Do post photos of the bay window Feltwell.

 

[Penners]

That's what I call a JOB, Feltwell! I'm not even remotely an expert on leadwork, but even I can tell quality when I see it.

 

[Feltwell]

Please post some details so that we can all learn how it's done and expect the same from other leadworkers... 8)

I think you already know what's been done Doug! But for anyone else:-

- A furring strip was placed along the back edge of the terracotta
- 3/4" marine ply was placed on that, with the front edge cut an angle. The furring strip means that the ply slopes outwards. The ply was very carefully fixed to the terracotta
- A bent strip of stainless steel ( at the bottom in the photo below) was fixed with copper nails to the ply
- Building paper was placed over the ply
- The lead was worked so it turned up the masonry at the back, across the top of the terracotta, down over the stainless strip and back over the bottom edge of it and back up again, to give a neat edge.
- Joints were put in as you see below, near to the corners, to allow for expansion
- Corner pieces were fabricated and fixed in place, then finally welded in-situ where the lead has to be jointed
- Flashing was fixed under the stonework above, overlapping the piece going over the terracotta



Hopefully that makes sense.

Interesting what you say Doug about using lead sealant then mortar over that for flashing. I can see why lead sealant works better than mortar, much better able to cope with the expansion and contraction of the lead than mortar, but it just doesn't quite look right against brickwork. It's been used on the porch above under the stonework, but you can't really see it there anyway.

Pictures of bay to follow when it's been done!

 

[DJH]

I agree. Most sealants are just not the right colour to match the colour of lead and can leap out at you when used in some situations such as white or light coloured walls. It doesn't help when in some situations lead can turn silvery grey and in others the patina is dark almost black. Sand coloured sealant is available which, with dust from existing mortar applied to the surface can look a bit more in keeping with surrounding mortar joints.

Doug

 

[Feltwell]

Today's instalment of "lead porn"......

Just about finished - just needs the flashing to be pointed into the wall and a tidy up. The brickwork has been rather butchered where someone has put flashing in before, luckily not only is the new flashing a lot neater but you won't see the join with the brickwork from the ground anyway.

The next time this roof needs doing, it should be someone else's problem - as I'll be pushing up daisies















The most time taken was sorting out the joinery beneath the lead. The old roof sloped the wrong way in part, and although the timbers were in good condition some had been butchered during a previous roofing job by the look of them. The whole roof needed to be built up in order to get the fall right but also in order to get the gutter to an acceptable depth, which also mean machining new taller fascia boards, hence the new looking softwood below the lead.

The rear gutter is in code 8 lead, really heavy stuff, and is turned up as far as it can possibly go on both sides - it should never leak in my lifetime. All very reassuring as really having the gutter at the back is not the best design ever.

Anyway, for lead work I can heartily recommend Quinn Bytheway in Stourbridge - top notch work, and a nice chap to deal with to boot. Give it a year or so for this lead to patinate and it will look like it's always been there. http://www.leadworkers.net

He's a plumber and is Gas Safe registered as well, so he's back next week to move the gas pipe that the original installer, long before I bought the house, decided they'd run from the external meter through a pane in my cellar window to get into the house, rather than drilling a hole through the wall... :roll: