flat roof repair / replace

wallofbeans

Hi All,

I've got a some kind of leak in the join between the original house and the flat roof extension to the kitchen. I'm looking at quotes for repair and don't know which way to go in terms of how to repair (there's been mention of 'hydro seal' and 'flexi tech') or if I should just be replacing.

Has anyone had this done or have any experience with this kind of work? It would be great to get some honest advice on the best options. I've had some quotes so far (with them just looking at photos) and repair seems to be just under 2k, and replace just under 5k. 

FreeBear

wallofbeans said: I've got a some kind of leak in the join between the original house and the flat roof extension to the kitchen. I'm looking at quotes for repair and don't know which way to go in terms of how to repair (there's been mention of 'hydro seal' and 'flexi tech') or if I should just be replacing.

It really depends on the detailing between the house and flat roof - Do you have any pictures ?

For a long while, had issues with my flat roof (extension on the side of an older house). Felt was laid with a small upstand on to the original wall, and then lead flashing over the top. Seems to be doing the job.

Kiran

What is the roof covering at present? Felt, hot melt, epdm (rubber) or fiberglass etc?

As above, any photos would be helpful

CliveOfIndia

I'm not sure if this would work in your situation, but I recently used this stuff on a leaking flat roof: https://www.wickes.co.uk/Thompson's-Black-One-Coat-Roof-Seal---5L/p/137244

It did a brilliant job at patching the leak, but I guess it depends on what's actually causing the leak for you.  But it's a dead easy DIY repair, assuming you can get easy (and safe !) access to the area in question.

wallofbeans

Hi All,

Thanks for the replies - picture below attached. There water damage on the ceiling inside - on the join between the flat roof and the original building, to the left side.

wallofbeans

CliveOfIndia said:

I'm not sure if this would work in your situation, but I recently used this stuff on a leaking flat roof: https://www.wickes.co.uk/Thompson's-Black-One-Coat-Roof-Seal---5L/p/137244

It did a brilliant job at patching the leak, but I guess it depends on what's actually causing the leak for you.  But it's a dead easy DIY repair, assuming you can get easy (and safe !) access to the area in question.

That could work, but yes I think it does depend of what is causing the leak - and I currently don't know, there is nothing that looks obvious, but I have no idea what I'm talking about so... 

stuart45

It's probably getting behind the lead flashing. Could be it's not cut very deep into the wall, and is relying on the Bellcast to hold it in place. If the render is cracked there it's possible to get behind it.

wallofbeans

Also, I bought the house three years ago, and I think the extension was put in before the previous owners, so the roof is probably 10+ years old. 

Albermarle

wallofbeans said:

Also, I bought the house three years ago, and I think the extension was put in before the previous owners, so the roof is probably 10+ years old. 

The roof should last longer than that, as said it is probably an issue with the lead flashing.

Kiran

Check the lead flashing is secure, and that the felt is lapped up against the wall underneath the flashing. The bell cast sits over the top of the flashing so double check there is sealant or mortar on top of the joint and no gaps. It looks to me that the bell cast has got some cracking too. How much water are you getting through? Are you talking about a damp patch or actual water running through? It would be worth getting some exterior masonry filler and raking out and patching the cracks and repainting and see if that solves the water ingress. The rest of the felt roof looks to be in pretty reasonable condition 

FreeBear

The actual point of water ingress may not be anything to do with the flat roof. I see a downpipe to the right, so I'd be looking to see if there are any leaks soaking the wall down the side. Check for cracks and other faults..

Had a leak in my kitchen that took a while to identify the source. Tracked it to a crack in the main wall some distance from where water was appearing in the kitchen. Fixed the crack and patched the hairline crack in the render, and haven't had a problem since.