Lean To Roof Flashing Leaking

[DickyDoDah]

I'm helping my son refurbish his house and I'm now onto the attatched garage roof. It's a lean to roof that leaks at the top when there is heavy rain combined with high winds. It is concrete tiles and I reckon it has been built with too low a pitch as I've measured it as 18 to19 degrees. it's not an option to change the pitch as that would be well beyond his budget. My guess is that the rain is being blown up the roof and under the flashing. I climbed on the roof today and measured the flashing and it is rather short. There is 150mm vertically up the wall and about 100mm on the tiles. Taking into account the amount inserted in the wall I'm guessing that the roofer used 300mm lead. What size should it be to stop the blown water getting into the garage?

 

[addjunkie]

No expert, but a close up might help, is it 1 piece or two?

 

[DickyDoDah]

I forgot to take a photo so that pic is from google streets It's one piece. Hopefully you can see a bit better on this pic. There's more up the wall than over the tiles which can't be good.

 

[gaz1]

go back onto roof again and look under the lead 150mm up the wall is too high whilst 100mm is too small

when your looking under the lead look at how many bricks are from the top of the garage roof

150 is about 3 bricks high

you can lower it but best to say how many rows are under the lead

 

[gaz1]

I forgot to take a photo so that pic is from google streets It's one piece. Hopefully you can see a bit better on this pic. There's more up the wall than over the tiles which can't be good.

View attachment 514561

from above you can drop it down one brick use a grinder to chase the cement out and recement the lead back into the wall

this will give you 150 on the roof itself

but id advise taking the last row of concrete slates off and fit a piece of felt under the slates and slightly up the wall before refitting the lead

 

[DickyDoDah]

I'll be back tomorrow so i'll get some better pics and also take a tape measure

 

[gaz1]

the felt adds a second layer of protection so if any blown water gets under the lead it will then go down under the slates

but that also depends if your roof is already felted

but note all the top row tiles need taking off and 1 latt needs removing before the felt goes back down and then relatted and then the lead rechased and cemented

if you dont want to do all of that just refelt under the lead but you will still need to remove the slates and the latt and leave the lead in place

 

[Agroshield]

What form are the tiles? Is there any gap between adjacent tiles on the top row that is letting water in?

I think the item described above is known as a 'soaker' and there are alternative (and possibly better) forms/materials for this than felt.

If the pointed joint holding the existing lead is sound, I would leave it alone. If you lower the lead, you have a joint to cut and two joints to re-point.

You could add a second line of lead, under the existing, that laps down further onto the tiles, which would do the same job but with a lot less work.

 

[DickyDoDah]

A few bits for me to look at and some good ideas I'll have a good root around and get a few pictures. From inside the felt looks to be in good condition but I'll need to lift the lead to have a look what they did.

You could add a second line of lead, under the existing, that laps down further onto the tiles, which would do the same job but with a lot less work.

That is a good idea and one worth considering. I've already looked at the cost of new lead and it's not as bad as I thought. What code lead should I be needing? The roof is 7m long so it won't be a cheap job.

I do have a roofer coming to quote so depending on the price I may end up doing it myself. It's been over 30 years since I last did any roof/lead work so I hope it's a reasonable price as I don't fancy the job Oh the joys of being retired and being free labour

 

[addjunkie]

Choosing Lead Code for Roofing | JTC Roofing

Understand the different lead codes used in roofing and how to determine the correct one for your specific roofing application and requirements.

www.jtcroofing.co.uk

Probably code 4,

Lead mate is wonderful stuff sticks to everything!

 

[Smallfry]

Choosing Lead Code for Roofing | JTC Roofing

Understand the different lead codes used in roofing and how to determine the correct one for your specific roofing application and requirements.

www.jtcroofing.co.uk

Probably code 4,

Lead mate is wonderful stuff sticks to everything!

It does. I have used it around upvc window frames and doors against creosoted (proper stuff) timber on our cabin/shed.

I didn't think it would adhere properly, but it has !

 

[knighty]

where/how does it leak? dripping/running down the roof, or running down the wall?

 

[Smallfry]

100mm is not enough on the tiles with that shallow pitch IMO.

Would be interested to see if there is underfelt or membrane below the tile battens. Ideally it could be lapped up the wall a bit, under the lead.

You could ease the existing lead up, take off the top row of tiles, which may, or may not be fixed to the battens, and add a strip of membrane and refix.

Could even add a bead of lead mate along the edge of the lead to seal.

I expect the roofer will want cash, and escort you to the nearest ATM

 

[DickyDoDah]

where/how does it leak? dripping/running down the roof, or running down the wall?

Running down the wall behind the wallplate.

 

[tom2207]

cant you just lift the lower lip and slide a flat piece with a lip turned up on it and put the top bit back over it ,,, use flashband if you have to but it would take a strong wind to blow it up under well fitted lead .

 

[gaz1]

I think the item described above is known as a 'soaker' and there are alternative (and possibly better) forms/materials for this than felt.

If the pointed joint holding the existing lead is sound, I would leave it alone. If you lower the lead, you have a joint to cut and two joints to re-point.

You could add a second line of lead, under the existing, that laps down further onto the tiles, which would do the same job but with a lot less work.

the tiles are ridge so 100mm isnt enough overhang for lead

height is not too low as its high enough anyway

options i wouldnt choose lead as its expensive and you dont need it for being a soaker

in this case the soaker being at the joint of the property where blowback is occuring

soaker options

felt, lead, tin, roofing profile tin, lime cement are all options to pick just to stop blowback under the lead but with lead length with ridge profile you need 150mm-200 on ridge profile tile

 

[roofman]

check the pointing on the lead chased into the wall, 100mm should be enough on those tiles and that slope.looks more than 18 degree from pic. water can creep up by cappilary action combined with wind,cheap fix is to lift lead up and run a tall bead of CT1 about 25mm up on the tile and dress lead back down onto it. My money is on the pointing as a lot of water will be running down that gable end if its getting blown onto by the wind, like standing there with 5 hose pipes.

 

[DickyDoDah]

I expect the roofer will want cash, and escort you to the nearest ATM

Actually they are doing another small job for me on Friday, the sewer vent pipe flashing is leaking a bit as it's lifted round the edges. A real PITA to get at and I would have ended up in a snotty pile on the floor if I'd gone up there. Only charging £80 to do it which is a good price I reckon. We shall see what they quote for the garage

 

[DickyDoDah]

I've been up on the garage roof and found the root of the problem. It looks like the lead will have to be replaced as it's cracked/split in at least three places. The pointing on the lead into the wall is OK, could be better but not terrible. I still reckon it could do with being a bit longer down the roof as I measured the angle again and it was18 - 19 degrees so quite shallow. The work at the end of the wall is also a bit messy. I'll see what the quote is and if it's more than my son can afford straight away I'll probably bodge it with some Lead Mate and change the lot myself next summer as it's not in a challenging position.

 

[roofman]

I've been up on the garage roof and found the root of the problem. It looks like the lead will have to be replaced as it's cracked/split in at least three places. The pointing on the lead into the wall is OK, could be better but not terrible. I still reckon it could do with being a bit longer down the roof as I measured the angle again and it was18 - 19 degrees so quite shallow. The work at the end of the wall is also a bit messy. I'll see what the quote is and if it's more than my son can afford straight away I'll probably bodge it with some Lead Mate and change the lot myself next summer as it's not in a challenging position.

its split because it was fitted with the lengths too long and stretched and shrunk every day when hot....should of gone in no longer than 1500mm. just put new bits of flashing over the splits 300mm long. If you think that lead is too short on tiles even though it has been dressed in very good then i cant advise you any further to save money.