Pointing over lead flashing

[worms]

What should be used to point the gap above lead flashing where it is grooved into sandstone?

Presumably this suffers badly from the expansion/contraction of the lead and needs to be pointed with something a bit flexible. Lime mortar? Burnt sand mastic? Or something more specialist?

 

[Gervase]

I'm afraid I cheat and use a modern stuff called 'leadmate', which is like a silicone mastic that you pipe into the groove. It's very flexible, which is ncessary with lead, as it expands amd contracts hugely with changing temperature.

 

[worms]

Thanks, I expected that this may be one case for something a bit more modern.

The place that is needing this let in some water during the recent heavy rain, but it may have been more a result of the exceptional conditions - A thunderstorm that stayed in the one place for a couple of hours. Nice sunny day less than half a mile away!

 

[geoff]

I used leadmate as well - with lead flashing (on lean to roof) grooved into rubble stone wall. It's lasted six or seven years so far with no problems on the most exposed wall of the house. Seems pretty good.

 

[andrew gayton]

calder, leadmate............. all the same goo.