Anyone seen lead do this?

[woodstalker]

Another leaking roof, this time flat lead roof over the bay window at the front. Went up yesterday and couldn’t see how the water was getting in. Up today and used as scrubbing brush up discover the lead has “dissolved” leaving holes:




I’ve filled them with CT1 for now but will have to get this one all off in the spring too…

 

[Mike G]

I'm struggling to understand the scale. I'd look for adjacent metal, initially.....copper or aluminium perhaps, because water + 2 different metals can set up nasty corrosive behaviour.

 

[Lons]

Mike might be on to it. Years ago I repaired the lead on a Victorian bay window and while not exactly like yours there was damage caused by copper roofing nails presumably dropped and left when the roof had been repaired. The owner said that was about 10 years earlier.

 

[woodstalker]

There are red/brown patches in some areas. I can’t see any other metals but around the edges of the roof there’s loads of white powder falling out from under it.

 

[Windows]

White powder could be lead hydroxide or lead carbonate indicating moisture under the lead roof which doesn’t necessarily tell you anything you don’t already know since you said it’s leaking and you found holes. But if you can see signs of white powder uphill of the holes that might be meaningful.

 

[Lons]

It's quite possible that the surface boards under the lead have been nailed and the heads of those have reacted, maybe even protruded in which case you won't see the other metals if involved. Water ingress would make the situation worse as the fixings would have rusted.

You could easily patch or over seal the lead but I would be looking at that as a temporary fix to be done properly when weather, time and budget allows.

 

[Tiresias]

We had a pretty catastrophic failure of a (big) lead valley gutter a few months ago. Bailing all night for two days to stem the damage until the roofer could get out. Top man – I wouldn’t have gone out on the roof in that weather.

Anyway, he reckoned it was lack of expansion joints, which had just repeatedly stressed the lead (it must have been a hundred years since it was redone) and caused it to fail eventually.

 

[woodstalker]

It's quite possible that the surface boards under the lead have been nailed and the heads of those have reacted, maybe even protruded in which case you won't see the other metals if involved. Water ingress would make the situation worse as the fixings would have rusted.

You could easily patch or over seal the lead but I would be looking at that as a temporary fix to be done properly when weather, time and budget allows.

Yes temporarily sealed and will be replaced in the spring with EPDM.

 

[woodstalker]

We had a pretty catastrophic failure of a (big) lead valley gutter a few months ago. Bailing all night for two days to stem the damage until the roofer could get out. Top man – I wouldn’t have gone out on the roof in that weather.

Anyway, he reckoned it was lack of expansion joints, which had just repeatedly stressed the lead (it must have been a hundred years since it was redone) and caused it to fail eventually.

So I believe the lead used is too thin, but like I say it looks like it’s dissolved.

 

[jimmy s]

It looks more like pitting corrosion than galvanic corrosion to me. I'd hope is wasn't copper nails that caused it as they are one of the recommended fixings for lead flashings, by the Lead Development Association.

 

[Mike G]

It looks more like pitting corrosion than galvanic corrosion to me. I'd hope is wasn't copper nails that caused it as they are one of the recommended fixings for lead flashings, by the Lead Development Association.

Jim, yes, you're spot on. I was in a rush when I used copper as an example...........although there is a galvanic effect, and is one of the reasons lead solder was phased out for copper pipes (where chlorine adds to the chemistry). There are lots of dissimilar metals which unite with water to cause galvanic corrosion, but I picked a poor one to illustrate the example of lead. One of the worst, I understand, is stainless steel, apparently.

 

[RogerS]

We had a pretty catastrophic failure of a (big) lead valley gutter a few months ago. Bailing all night for two days to stem the damage until the roofer could get out. Top man – I wouldn’t have gone out on the roof in that weather.

Anyway, he reckoned it was lack of expansion joints, which had just repeatedly stressed the lead (it must have been a hundred years since it was redone) and caused it to fail eventually.

Been there. Got the damp patch. Our last place the lead in the gulley had, like you, very few expansion joints. Over the years, expand, contract, expand, contract had caused small raised 'dams' with a lovely crack along the top of each of them. That was probably 20+ years ago and there was little on the market at that time. Finally tracked down a two-part American product which cost an arm and a leg and came with dire warnings about timescales during the application.

Unluckily for them, Jehovah's Witnesses arrived while I was struggling up on the roof as the wind had unexpectedly picked up and time was running out but that is another story. Think we were blacklisted.

 

[Mike G]

Unluckily for them, Jehovah's Witnesses arrived...... Think we were blacklisted.

Bonus!

I ask them to put me on a list to not receive visits..........and of course, every 2 or 3 years they drop in "just to keep our list up to date".

 

[Blackswanwood]

This article from English Heritage discusses the issue of lead corrosion…

Lead Roofs and Statuary: Understanding, Monitoring and Conservation | Historic England

Research into treating corrosion and staining in historic lead roofs and statues.

historicengland.org.uk

 

[Lons]

Bonus!

I ask them to put me on a list to not receive visits..........and of course, every 2 or 3 years they drop in "just to keep our list up to date".

I just point to the gates, say the beware of the dog sign (there isn't one) is there for a reason and as she's roaming the garden somewhere to be careful as they leave because she bites. The dog would lick them to death but they don't hang around to find out. Being an old Lab she's usually sleeping in her bed rather than roaming the garden.

 

[Dr.Al]

I ask them to put me on a list to not receive visits..........and of course, every 2 or 3 years they drop in "just to keep our list up to date".

This might well be apocryphal, but someone once told me that an effective way of getting rid of them is to tell them you were excommunicated

 

[RogerS]

I just point to the gates, say the beware of the dog sign (there isn't one) is there for a reason and as she's roaming the garden somewhere to be careful as they leave because she bites. The dog would lick them to death but they don't hang around to find out. Being an old Lab she's usually sleeping in her bed rather than roaming the garden.

They had to get out of the car to open the gate to the house and were in line of sight of me up on the roof. At the end of our 'discourse' they asked if they could drive in and turn round. I shouted 'No...Foxtrot Oscar' and watched as they reversed back down our twisty track. All 3/4 mile of it

 

[Ovaloe]

This might well be apocryphal, but someone once told me that an effective way of getting rid of them is to tell them you were excommunicated

Nah! Just tell them you've recently converted to Islam and invite them to discuss the life and times of the Prophet. It worked for me