Fixing crack in corner of roof lead

[Tim Watts]

Hi,

Whilst painting the gutterboards, I noticed this:

It shows a crack where the lead has been folder around the corner of the bay window deck. rest of the lead is fine. Possibly stress cracked due to the walking on it got whilst the roof was being done - no blame there, stuff happens and it's minor :)

I'm wondering how best to repair it?

1) Hot solder the crack - or hot solder a patch over the corner?

2) Make a corner patch and glue it on with cold lead sealant?

(2) is of course easy and risk free but 1 would probably be better?

if (1), I think a regular blowtorch would be enough - without too much risk of igniting the deck or dust nearby. Not done this before but seen lead pipes being wiped. Is it still the form to use a stick of plumbers metal and tallow as the flux?

Cheers :)

Tim

[Andrew Mawson]

It is possible to do a wiped joint in that situation but it takes practise and is an acquired skill. If you have some scraps of lead, make a mock up and have a try. The difference between nothing much happening, and it all trickling out down the joint is very little. You are aiming to get the lead tinned over all the edges, then the solder in the pasty state so it can be formed where you want it. Choose your solder carefully, it needs a slightly lower melting point than the lead, and needs to be non-eutectic so it has a pasty range. Modern lead free solder will not work in this situation.

AWEM

[Dave Plowman (News)]

I repaired a crack using the solder and flux I use for copper tube. Used a jeweller's blowlamp with a small flame. The solder I used contains lead - lead free for potable water may have too high a melting point. Proper plumber's metal probably lower still.

I could be wrong, but I don't think tallow is a flux. It's used on a wipe to prevent the solder/lead sticking when forming things. It's basically fat and oily things don't usually get on with solder.

[Tim Watts]

On Tuesday 19 February 2013 15:36 Dave Plowman (News) wrote in uk.d-i-y:

Oh - that would make sense.

What's a good flux for a lead joint?

Cheers :)

Tim

[Tim Watts]

On Tuesday 19 February 2013 15:54 Tim Watts wrote in uk.d-i-y:

Baker's No 3 by any chance? Just seen it on ebay.

Jeebus - 30 quick for 2 sticks (1kg) of plumbers metal!!!

[Dave Plowman (News)]

I just used the Everflux which is really for copper pipes. It's water soluble, so easy to wash off afterwards.

There will be someone along shortly to say this was a mistake. But the repair has held up for years - it's on part of my roof terrace so easy to get at.

[harry]

Lead burning is not done in situ near to timber usually, too much risk of starting a fire. I would get some flashband to stick on it. Make sure you have a good lump on the flat surface bending over the crack. If just on the vertical it may peel off in hot weather. You will need to warm things up to make it stick this weather.

[Tim Watts]

On Tuesday 19 February 2013 16:56 harry wrote in uk.d-i-y:

I did think of that.

The lead will lift slightly - should be possible to slip a soldering heat mat under the lead and over the deck.

I also have some 80mm vents in the soffit of that section so I can look up and under that bit of deck to check all is well.

However, point noted.

Flashband could work - it had slipped my mind. Just wondered how long it would be good for...

[sm_jamieson]

When I over-worked the lead flashing around my solar tube and it broke thro ugh, I tried to weld / solder in a new piece, but did not really know what I was doing and ended up melting out a larger hole. So I tried another approach. I repaired the hole with liquid rubber, including an impregnated piece of f abric on the underside to give it strength. The stuff bonds very well to le ad (a bit like the rubber / lead soil pipe flashing "slate"), and has been fine for a few years so far with no signs of it lifting or deteriorating at all. Simon.

[Dave Plowman (News)]

Easily done if you use a large flame blowlamp. I found a jewellers one quite easy to use. But I'm fairly experienced at soldering. What would be ideal for the novice would be a large enough temperature controlled soldering iron. But that wouldn't be cheap even if such a thing exists.

[Jonathan]

Stained glass makers have them for soldering the leading joints in a window. My cousin who makes glass has one.

Jonathan

[F Murtz]

Just use a big soldering iron,flux and solder.

[Dave Plowman (News)]

Yes - I can imagine that would be fine for the joints on a leaded window, but a big chunk of lead like you find on a roof would conduct the heat away more readily?

[Dave Liquorice]

If you get it well applied it'll last very well. Just need to make sure it is well applied a seam roller is good for making sure it has intimate contact and as much air is excluded as possible. At this time of year you will need to make the roof and the flashband warm.

I used some to cover the frame around an access hole I cut in a zinc covered flat roof. When I moved out 15 years later it was a good as new. IIRC I also covered the access cover with it in overlapping strips.

[Jim K]

cooks blowtorch?

cheap enough £5 or 6 IIRC

Jim K

[Tim Watts]

On Wednesday 20 February 2013 22:20 Dave Liquorice wrote in uk.d-i-y:

I think, for a 1" crack in a non critical location (it won't make the roof leak inside the house, just risks rotting the deck) that this is probably a better idea than trying to hot solder on top of wood :)

[Dave Plowman (News)]

The temperature needed to melt solder is nowhere near high enough to ignite wood. It's the blowlamp which is. Using some form of soldering iron would solve the problem.

[Tim Watts]

On Thursday 21 February 2013 10:24 Dave Plowman (News) wrote in uk.d-i-y:

I cannot see any sort of iron (even a massive electric one with an inch wide shaft and tip like my dad had) heating the corner of code 4/5 sheet. Even my blowtorch is going to have a bit of work on its hands.

However, I did wonder about putting a strip of lead around the corner of the deck, under the split. That would shield the tiny amount of exposed wood (which I think it would be nearly impossible to ignite and sustain ignition anyway, being right on the corner) and would act as a repair bridge for the joint, rather than relying on trying to solder bridge 2 edges.

After all, lead pipes were not butt jointed; one was flared over the other to get an overlapped joint. This would be similar...

[Mark]

If you were considering paying a professional to repair it, i could recommend a chap who specialises in lead roofs.

-

[Tim Watts]

On Thursday 21 February 2013 16:16 Mark wrote in uk.d-i-y:

Thanks - but it's so small, I'll fix it myself :)