roofing question

Lead lasts forever but is expensive, the other stuff is cheap but weak, splits and comes unstuck.

I've just redone the pointing and flashing on my chimneys and raked to 15mm where the flashing is, which is about the original depth, but deeper the better I guess.

-- Mike W

Well, lead should last a lifetime and is *very* satisfying to work...

With lead, enough to jam it in place securely before re-pointing, so about an inch.

Round our way the seagulls love Flashband. They just peck away at it and rip it off in shreds.

ken

The advantage of the lead is that it prevents water entering the building at the join between the wall and roof. The stick on flash band does not have this useful property.

Christian.

Go for the permanent solution - use lead. The stick-on stuff is rubbish and always leaks in my experience, especially if it's in a location that's exposed to the sun and the prevailing wind direction.

Mike

A quite desirable property, thanks to all who replied. I seem to be able to get lead from sheds in 3m lengths, where my longest run will be double that, anywhere sell longer? (then I might need a forklift to get it up to the roof though)

If I stick with the 3m lengths, is an straight overlapped joint ok, or better to aim for a wrap around like so?

--------------\ /------------ /--- | | | ---/ | \------/

Because of expansion max length should only be 1.5 m, with adjacent section overlapping by 150mm. Rake out to about 1". Insert length od lead and some approx 1" wide rolls jammed in between the lead sheet and the top of raked out joint (about 3 per length). Cement in place. If possible make the folds on the ground before inserting into raked out joint as it is safer and gives a neater edge.

I just overlapped mine, but put a small bulge in (about 5mm or so), so the water would have to go uphill to run underneath. I also used a substantial overlap. No sign of any water ingress.

Working with lead is great. It must be the nicest material I've ever used. It cuts easily. It bends easily. It stays exactly where you put it.

One tip. Make sure you apply patination oil before installation. I generally did, but forgot one piece, which does look significantly more manky than the other bits.

You have the choice of sealing with mortar or lead silicone. I went with the lead silicone as it is less work, as you don't have to mix up the mortar and carry a bucket up there.

Christian.

As others said, don't use runs of more than 6' to avoid expansion problems.

One useful trick I found: Having raked out a suitable groove to insert the lead, you can use small strips of lead rolled up into a cylinder to wedge into the grove every so often above the lead. This holds it firmly in place before you apply the sealant or mortar.

Best is soldered, to me: However, when my lads were laying flashing, THEY said that more than 1.5 meters should not be laid as a length as expansion/contraction would rip it apart..since it was a sloping valley, they simply overlapped it. I like the solution you have below though - for a flat roof it should be good.

The usual way is a 'zig-zag' formation so you can make it any thickness. Then tap in place with a drift which will open it out.

Fancy tackling that in ASCII art?

Oh, easy:

\/\/\/\/\/\/\/\

;-)