Boiler flue leaking in rain

Swtastic

Symptoms:
When it rains, as you can see from pictures, water comes in and leaks through the boiler.  The ceiling also shows water ingress.  The roof is north facing.We have tested with the hose and water is coming in somewhere from the mid to lower part of the external flue. When we simulated rain (from the hose) to the top of the flue in the vent/cap area, no water ingress.  I asked a DIY mate to seal everywhere he could and he did but water still came in, in smaller quantities though.  My husband then used the black sticky roof seal to seal the cuff bit as best he could.  Yesterday when it rained, more water ingress but again in smaller quantities.
Result:  it's got in the boiler and now it isn't working and we have an error code but that's a separate issue.  Engineer booked on Monday but no hot water/heating in the meantime.  I fear this will be expensive but that's another story.

I need to get this sorted as otherwise we will have on-going boiler issues.
Can anyone advise please?   I'm grateful for your help.

casper_gutman

I'm no expert but that flue doesn't look right to me. The top of the flexible black flashing part at the bottom surely shouldn't be reliant on all that sealant to keep it weatherproof.

I'd have thought the outer black cover should extend down to overlap that black flashing part, to cover the white inner flue completely.

Tucosalamanca

Roofer here.
It could possibly be the vent tile, although to the rh side where vent meets flashing it appears to be damp slightly higher up, so possibly the lead flashings as well. And having looked more carefully, ridge tiles appear to have had previous pointing repairs, so possibly an issue there too.

As a side issue, I too don't think that the flue has been installed correctly, I'm also wondering about its location.
It's very close to the Velux window (from memory should be quite a distance), and within 300mm of boundary wall, is this installation building regs compliant?
I don't know the exact details, can anyone with more knowledge confirm?

I think you firstly need a gas engineer then possibly a roofer afterwards.

FreeBear

Tucosalamanca said:  As a side issue, I too don't think that the flue has been installed correctly, I'm also wondering about its location.
It's very close to the Velux window (from memory should be quite a distance), and within 300mm of boundary wall, is this installation building regs compliant?
I don't know the exact details, can anyone with more knowledge confirm?

I think you firstly need a gas engineer then possibly a roofer afterwards.

600mm horizontally & 2000mm vertically from an opening velux type window, and 300mm from a boundary according to Part J - See secion 3.23 on page 48-51. Diagram 35 on p.51 being the most important one.
The installation doesn't appear to be BR compliant, so a registered Gas Safe engineer should be consulted.

casper_gutman

Good point about proximity to the Velux. We had an issue with that on our extension, which was resolved by making the Velux non-opening (basically by screwing through the frame into the opening sash from the outside, before the flashings were fitted - Velux will supply instructions if asked).

The distance from the boundary wall would be rather harder to change!

FreeBear

casper_gutman said: The distance from the boundary wall would be rather harder to change!

It is a low parapet wall - As long as the top of the flue is high enough, I suspect you could get away with it. But an expert opinion should be sought to confirm either way.