Leaking Flat Roof - Help Please

[rossyl]

Hi

Please go easy on me - I am far from a competent DIY'er, I have called out experts, and this is the situation I am currently in. I've tried to provide as much detail as possible - but no doubt as a layman I am missing information. Please ask for any additional info.

I would greatly appreciate some advice.

We have a flat roof at the very top of our house above a loft conversion. It is torched on felt. It is leaking onto the plaster board ceiling below, it is not much water, but enough to be annoying.

The roof is 6 years old.

We did not have a leak until the end of last year.

This is how the roof originally looked, we have been told that's it's 'Join City' - with lots of joins and insufficient flashing. However, it did hold up without leaks for 5 years.

ATTEMPT 1 - PROFESSIONAL FIX

We called out a specialist London Flat Roofing company. They said that they would "seal the walls either side of the chimney and the chimney breast"

When it came to doing the work, lockdown hit and I could not get him to come out. So we found another roofer.

We had a roofer who "burned on" all the joints around the chimney. He said that he checked the joins on the chimney and the wall and they all looked good and would not be shifting.

The leak still kept coming.



ATTEMPT 2 - PROFESSIONAL FIX

Roofer's second attempt was to cover the area in Roofing Acrylic Paint. It slowed the Leak, but did not stop it.



ATTEMPT 3 - DIY

Given that all the previous roofer was doing was effectively slapping on acrylic paint, and it had partially cured the issue, we then did a second coat of Cromapol acrylic roofing paint.

However, that has not solved it, and the leak has now return possibly to how it was before.

Cromapol...in the photos below
You can see the whole chimney is covered in Cromapol.
The bit in front of the chimney is covered in Crompaol.
A bit either side of the chimney is covered in Cromapol.



ADVICE PLEASE:


Should I

1. Try and get another roofer to add flashings, or has that ship sailed due to the Cromapol.


2. Go up there and cover more area in Cromapol - if so where?

I can see areas where water is pooling. I can see joins on the wall that I could maybe cover/recover in Cromapol. What do you think?


This leak is really really annoying - so advice is much appreciated. Thanks


Here is what it looks like now, took this today (using a GoPro on a stick) an hour after it rained

 

[^woody^]

Where is the dampness inside the room?

If it's on the wall the problem would mote likely be related to the parapet or the chimney flauncing directly above it.

Ponding is not necessarily related to leaking and if there is standing water then the joints must be intact.

 

[rossyl]

Thank you very much Woody.

It is against the wall.

The leak is a drip. It seems to drip with some "force" which makes me think it is dripping from a distance If that makes sense?

Here's a picture of the leak. The area is similar size to a down lighter

Woody - I'd be grateful for any thoughts you had to try and fix this, or next steps.

Thank you

 

[HERTS P&D]

Take the light fitting out and see if you can see where the leak is, you can stick an Iphone up there and take a video.

Andy

 

[rossyl]

Thanks good idea.

I can try, but the light fitting is a bit far from the leak (though appreciate it looks closer in the photo)

Will give it a go.

 

[rossyl]

Thanks again Andy.

I gave it a shot, but was met with this.

I tried to pull it out, then lever it out, but looks like it's been pushed into the plasterboard, or the fixings have been filled over.

So, apologies, I was unable to take a photo from inside the downlighter hole.

 

[^woody^]

Pull that plastic fitting down, it will come out, there are two spring clips thats all

Try to see the underside of the roof deck to see if there is widespread staining or none, or just a bit above that drip

Is that blue dot in the first photo the area directly above the leak spot?

 

[rossyl]

Yes -blue dot in first pic is roughly where we think the leak spot is.

Or, we were wondering if it was coming down the actual chimney (which are capped)?


I also managed to take a better photo showing the Cromapol area.

 

[rossyl]

Managed to get the light fitting out, that was a fiddly. Thank you for the advice, and giving me the confidence to do that!

Unfortunately the joists run right in front of the spot where the leak is so I cannot see the leak.

However, at least it looks dry here. (managed to combine an old GoPro and a headtorch to good effect)

Given it was dry everywhere that I could see, in my below-average-DIY (non-roofer) mind, that does point to it coming down the wall?

Any other thoughts or suggestions of next steps?

 

[HERTS P&D]

You could drill a hole where the leak is and look from there. Fixing the hole is quite easy to do.

Andy

 

[Bosswhite]

The Chimney stack seems to be badly covered, at Rear of Stack (neighbours ) not treated at all suggest get someone to check it out , maybe treat and cover all of it with roofing glass fibre .
Leaks never appear where the rain comes in ( Building Fact !!!!)

 

[rossyl]

The Chimney stack seems to be badly covered, at Rear of Stack (neighbours ) not treated at all suggest get someone to check it out , maybe treat and cover all of it with roofing glass fibre .
Leaks never appear where the rain comes in ( Building Fact !!!!)

Happy to cover the whole top of the chimney with Cromapol - https://www.cromarbuildingproducts.com/products/cromapol/

If that seems a sensible next step.

 

[rossyl]

Forgot to possibly importantly mention.

The fireplaces/chimney breast have been removed on our side of the house. The chimney's remain, I'm not sure what they are doing, but, there is no chimney breast in the house at all. It was removed approx 6 years ago, when the loft extension was done.

Building control seemed good, they were private and chosen by us, so I think it was a job done well.

 

[rossyl]

Here is a video of the inside of the ceiling.


The camera goes up facing the directly in front of where the leak is (unfortunately with a joist in the way). I then do a pretty slow 360 view.


I think it looks pretty dry. Note that there are no other damp spots on the ceiling.

 

[rossyl]

Drilled another hole. Found the problem. Video on the way...

How do you make a chimney cap completely water tight?