Bay window with lead roof leaking

[Adam78]

Hi,

I have a bay window which appears to leak in heavy rain from the top frame - see pics which show droplets of water which have trickled down between the frame joint ( this joint is roughly where the mortar line is on the outside) and overnight it ends up leaving a huge pool of water on the window sill.

The window has a lead roof where the lead is fitted into the mortar chase and then mortared over.

I've got up with a ladder to have a look at the roof and I couldn't see any obvious signs of damage to the lead roof itself. However I did notice a split in the lead on the outer edge and also the mortar line where the lead is chased in doesn't look too great and appears to be porous and loose.

So would I be correct that it is mostly seeping through the mortar and behind the lead down into the frame?

Whats the best way to repair that mortar line. Do I rake it all out and repoint or do I use some lead sealant to seal up those lose joints? If I try to rake it out its risky that I may end up damaging the lead.

Also how do I patch up the split at the front of the roof. Would some bostik flash band do?

Any advice appreciated.

 

[blup]

It does look that way, lead should be tucked into brickwork

 

[DAZB]

You can chase out the mortar fairly easily with a narrow stone chisel or even an old flat screwdriver and it looks like it would not take much effort. The leadwork would not be damaged if you take it easy and it can then either be mortared back in or use a sealant such as Leadmate from Screrwfix / Toolstation etc... and if you gently prise up where the split is get some sealant under that too and bed it back down.