Hairline leaks in inaccessible lead pipes

[ScarletPimpernel]

I know this subject has been discussed before, so apologies if it seems like covering old ground, but we have an old lead pipe that's driving us crazy!

It has a hairline leak and is spraying a fine mist under the floorboards in our top bedroom. This water is then "seeping" along the downward joists and causing damage to all areas beneath it. It is hard to get access to it as it's in the corner, it's impossible to get compression joints on two ends. I can't even put a "bandage" around it without digging a large hole in the ceiling of the room below.

After much detective work, we followed the pipe sunken beneath floorboards, it seems the pipe comes in the house at the front into the cellar, then runs upwards (to where the old Header Tank would have been I guess), then along the top of the house, under the floorboards where it's "sunk" beneath the main joists where they seem to have dug-out a sort of "mouse-hole" shape to accommodate the lead pipes.

I know that lead pipes are BAD NEWS, but our problem is that it supplies cold-water feed to the whole house, and therefore we need a fix for now - until we replace it all with plastic.

Does anyone know how to mend this pipe with restricted access? Is it enough to GENTLY knock it with a heavy hammer 20 times then squash on some Milliput? I've tried pouring some molten lead onto the pipe but it doesn't create a strong enough bond to adhere.

 

[ChrisR]

DON'T HIT IT HARD!

You could try tapping it. It's hard to convey HOW hard, but you want to just ding the surface.
If you use an all-metal dining knife, hold the blade, and knocked it with the handle edge, that should do it. After a few dozen tiny dents they all merge together.

If you can lightly scrape it clean first that would help.
If you try some sort of epoxy, turn the water off, to get the pressure off, dry it all with tissue and a hairdryer, and score the surface enough to make a key.

Might be best to go back as far as you can , use a lead-loc or similar and a plastic pipe temporary lashup, WOuld save a flood.

 

[Onetap]

I know this subject has been discussed before, so apologies if it seems like covering old ground, but we have an old lead pipe that's driving us crazy!

It has a hairline leak and is spraying a fine mist under the floorboards in our top bedroom. This water is then "seeping" along the downward joists and causing damage to all areas beneath it. It is hard to get access to it as it's in the corner, it's impossible to get compression joints on two ends.

Apply crowbar. Restricted access becomes easy access. Fit 2 Leadlok connectors, or 1 Leadlok and rip out all the lead up to the tank or from the main stopcock.

You will be doing this eventually; if you do it now, you may not have to go to the additional expense of replacing the joists that have become saturated and infested with dry rot or woodworm.

It was the cold water rising main, probably with a branch to serve a kitchen sink. Get rid of it.

 

[ScarletPimpernel]

Thanks for the tips ChrisR and Onetap,
I can see many furrowed brows when lead pipes are mentioned, not surprisingly!

Your comments about dry rot and replaced joists are well-made. I have asked local plumbers to price up replacing the whole system. It's an inevitable job I can see.

But for now I'll try ChrisR's advice and get the main thing done later this summer.