Leaking garage roof around boiler flue

[Davejohnson78]

Hi all,

I would be really grateful for any thoughts or advice. Really struggling to know where to go with this next.

We had a new boiler installed about a couple of years ago. It is in the garage and the new flue goes through a new hole that was cut through garage roof boards. The old flue was apparently too close to an external wall. There were no issues until last autumn and i noticed during heavy rain we woumd get damp patches appearing on roof board around flue and if heavy enough would also get water collect in bucket below.

The garage felt roof was tired and in need of replacement so I thought I would replace it and should fix problem. The roofer was meant to inspect and replace any collar kit around the flue at the same time but chose not to as thought just covering with the new felt would be adequate.

Unfortunately I am still getting water leaks around flue, despite new roof. Roofer has been back and says he doesnt think its roof and that water must be tracking from elsewhere - I dont believe this.

There is no water getting in elsewhere and no water leaks through the old flue hole just a few weeks ago.

Where should I go from here? Rip new roofing off and start again, get boiler engineer to check flue and fixings, pull felt off around flue and fit new weather collar underneath?/

Thank you so much for your help.


Pictures:
See first picture for image of the old roof. At back of the roof is a box gutter - this is not leaking and clear and drains fine and doesnt overflow during heavy rain.

Picture 2 is the damp area leaks you get around flue.

Picture 3, 4, 5 are the new roof and the felt around the bottom of flue. This now also has the addition of some extra seating and felt around the collar.

 

[DAZB]

It looks like the roofer has cobbled together a handmade felt sleeve around the pipe and tried to form it to the deck felt which is where i suspect it could be entering. It really needed something like this :

Master Flash 140-292mm (5.5-11.5) - Low Temp EPDN No:7 - £44.34 :

Master Flash 140-292mm (5.5-11.5) - Low Temp EPDN No:7 - Flashing provides a weather tight seal for Twin Wall insulated flue to pass through a roof surface. The flexible silicone cone allows for movement in the pipe and the base is designed to fit the contours of any roof type other than tiled

www.glowing-embers.co.uk

I would have the roofer back as he has done a poor job of installing it in my opinion.

 

[^woody^]

May be something simple such as the collar or lack of.

 

[Davejohnson78]

Thanks both. Would it be easy enough to remove that local area of felt to sort or fit collar or am I going to have to re felt the entire roof again.

 

[^woody^]

The collar is what goes around the flue to act as a shroud for the felt upstand.

You have that shiny metal thing there now, and it's not clear if it's acting as a collar and forming a good seal.

If there are no obvious gaps in the felt joints then the felt won't be at fault.

What about those screws from that bracket crudely screwed into the deck, they have not punctured the felt have they?

 

[Davejohnson78]

Thanks so much. This is what’s driving me slightly mad. The roofer has been back and double checked all the seals around it. I’ve got to agree it does look like a decent job has been made to seal around it with the felt.

The problem is if it’s not getting in there I can’t figure out why water is leaking around flue? Can’t figure out where else problem might be to allow me to make a plan to address?

 

[Davejohnson78]

Anyone got any further ideas on potential source of leak to try and direct next steps?

Thanks