Repairing roof flashing

tony3619

Hello

I recently posted about a balcony roof leak that happened during the February storms and I have finally been able to cause the leak in the same place by pouring water on the joint where the flashing meets the wall. 

Now that I know where the water is entering any suggestions on how to repair it without spending thousands on a new roof? There is movement when I press on the flashing so it's definitely not bedded correctly. 

Regards 

greyteam1959

Rake the loose mortar out & use the appropriate sealant from Toolstation or Screwfix.

Jonesya

You can get flexible gray sealants for pointing lead flashing into the wall, they're typically silicone based so are much more flexible than mortar. You could try removing the mortar and sealing with one of these, or at the very least use this to seal areas where the mortar is missing.

https://www.toolstation.com/lead-mate-sealant-300ml/p33704

https://www.screwfix.com/p/geocel-trade-mate-roofers-seal-lead-grey-310ml/72630

tony3619

Thanks for the replies

It does make me wonder why they didn't use sealant to start with? (it's a new build property) It's not lead flashing it's rubber,  the same material as the roof. 
I was going to ask a roofer to put new mortar in? Is that a waste of time? 

starving_artist

Apologies for hijacking this thread - my neighbour's builders damaged the flashing when they drilled through the wall to make a new pipe connection.

This is the repair

Does that look acceptable??

tonyh66

picture 1 grey pipe, picture 2 and 3 black pipe? is that the same job???? also in all of the pictures, there is a gap between the existing vertical flashing and the roof so it has always been defective the new work did not cause the problem.

greyteam1959

tony3619 said:

Thanks for the replies

It does make me wonder why they didn't use sealant to start with? (it's a new build property) It's not lead flashing it's rubber,  the same material as the roof. 
I was going to ask a roofer to put new mortar in? Is that a waste of time? 

Rake it all out all the way along the flashing & use a flexible sealant.
If you put new mortar in it will just crack out again in a matter of months.
Why did they not use flexible sealant = cost..........

tony3619

greyteam1959 said:

tony3619 said:

Thanks for the replies

It does make me wonder why they didn't use sealant to start with? (it's a new build property) It's not lead flashing it's rubber,  the same material as the roof. 
I was going to ask a roofer to put new mortar in? Is that a waste of time? 

Rake it all out all the way along the flashing & use a flexible sealant.
If you put new mortar in it will just crack out again in a matter of months.
Why did they not use flexible sealant = cost..........

Point taken about cost.....most things in this house are built to minimum specs so I don't know why I would expect any different! Would you recommend any type of sealant meant for brick to rubber? Would I be better of getting a roofer to do this or is it easy for a fairly competent diyer? 

tony3619

Also does this require lead flashing to be installed above the existing upstand or will sealant on its own do the trick? 

starving_artist

tonyh66 said:

picture 1 grey pipe, picture 2 and 3 black pipe? is that the same job???? also in all of the pictures, there is a gap between the existing vertical flashing and the roof so it has always been defective the new work did not cause the problem.

Yes - they replaced the grey pipe with the black one.  You can't really see in the photos but the gap between the bottom of the existing flashing and the roof was sealed with mortar.  The repair was just supposed to be to make good the bit they shaved off at the top when they drilled through.  Should that new flap be sealed with on the bottom and sides with mortar?

tonyh66

the vertical flashing should overlap over the top of the horizontal flashing/roof otherwise water will follow the path of the opening and into the building.