Leak in bay window

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Hi all. After some advice please.

12 year old house. A couple of weeks ago, in amongst all this horrendous rain, our bay window started leaking with water coming in from the ceiling (of the actual bay). I drilled a couple of holes to catch all the drips in a bucket.

roofer #1 came out and diagnosed failed sealant and water ingress through the horizontal bit of flashing. He replaced the sealant with a mortar mix. As soon as it started raining again, the leak came back.

Roofer #2 went to town and did the whole bay window roof (new felt, batons, drip trays, used hip flashing that wasn't present before etc). This was after checking the loft and not seeing any ingress from the (false) chimney. He also went round with sealant on any potential gaps (bottom corners of the faux window for example).

A week went by, and no more leaks but we then had loads more rain last night and the bay started leaking again. Roofer came round again and lifted the flashing and showed me that the underside of the tiles, felt etc were bone dry in the bay, but the bricks behind the flashing were wet.

He noted how absolutely sodden the brickwork is across the entire gable end (even after no rain in the night). He's thinking the brickwork is so sodden that water is possibly getting into the void, running down and seeping through the blockwork that is behind the bay window roof.

He is going to have a proper look at the chimney again but has suggested using thompson's water seal across the whole gable end given how sodden and how much of a battering it gets (we're on a corner so there is no protection from wind/rain). He is also considering whether the flashing needs to be chased in further than usual.

I feel like this could be an absolute time and money pit of trying to find the issue particularly if we start any invasive work of removing bricks etc. Is there a genuine hole somewhere that needs to be found (and patched?) Is there a badly installed cavity tray above the bay? Has the weather just been so bad that we need the water seal? I'm hesitant about using the latter as (even it worked) feels like a sticking plaster on a bigger issue? Apparently the seal only works for a few years so don't fancy bearing that ongoing job.

Absolute nightmare!

Cheers

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I'd have another look at that fake window. I had a similar issue in the old house and discovered that it was a 0.5mm crack in the sealant around the window letting in over 1 litre of water per hour in heavy rain when the wind was blowing in a certain direction. Obviously you don't have an actual window there, but still.
 
Thanks. I've got someone coming out on Friday with a borescope.

The best I can hope for is that we have cavity trays but nobody bothered putting the weep holes in.

Had a look round some other bay windows on the estate, most have 3 or 4 weep holes going horizontally just above the flashing. Mine and a few others don't have any....
 
has suggested using thompson's water seal
Lol. A bodger.

There are times when a surface water repellent may be appropriate, but it's never Thompsons - that's for DIY on your garden planters.

If such a solution is to be done, then a silane/siloxane product is used and that costs 4x as much and lasts 20x as long as Thompdons.

Where is the water exiting internally?
 
Lol. A bodger.

There are times when a surface water repellent may be appropriate, but it's never Thompsons - that's for DIY on your garden planters.

If such a solution is to be done, then a silane/siloxane product is used and that costs 4x as much and lasts 20x as long as Thompdons.

Where is the water exiting internally?
If I was going down this route, I think Stormdry is the way to go?

Water us existing at the front of the bay window (was seeping out between ceiling and window frame, before I drilled a few holes in the ceiling to at least direct the water to one location.
 
Looks like you need a stepped and horizontal cavity tray above the flashing. And weep holes.

At 12 years old, you may just be in time to make a latent defect claim against the developer and/or the warranty provider (NHBC?).
 
Looks like you need a stepped and horizontal cavity tray above the flashing. And weep holes.

At 12 years old, you may just be in time to make a latent defect claim against the developer and/or the warranty provider (NHBC?).
Thanks for this. I think i'm going to be outside of any claim period (think it expires after 10 years).

Most other houses on the estate have a few weep holes running horizontally directly above the flashing. So presumably just a horizontal cavity tray? I can't see any with the stepped set up (rightly or wrongly). There are a few houses (including mine) which don't have the weep holes at all.

I'd much rather do a proper job (vs stormdry) but obviously comes a point where the cost/risk might be prohibitive.
 
Thanks for this. I think i'm going to be outside of any claim period (think it expires after 10 years).
Latent defect and contract claims are under common law, not a warranty claim.

Under contract law, if valid, you would have 12 years to make a claim against the NHBC for their negligent inspections for the warranty - these are not and distinct from the building control inspections.

Under latent defects (negligence), you may have 15 years to claim against the builder/developer.

If you have legal cover on your home insurance, ask for advice.

Any cavity tray should follow the roof profile. A purely horizontally tray leaves a section of wall between it and any angled roof, and that is susceptible to water penetration.

Clearly the builder's of your estate did not know how to build properly, and managers weren't bothered with quality.

BTW, if you come to sell at some time, and a clued up surveyor sees any window or roof like that without weep holes above, then that's an immediate red mark in the report.
 
Latent defect and contract claims are under common law, not a warranty claim.

Under contract law, if valid, you would have 12 years to make a claim against the NHBC for their negligent inspections for the warranty - these are not and distinct from the building control inspections.

Under latent defects (negligence), you may have 15 years to claim against the builder/developer.

If you have legal cover on your home insurance, ask for advice.

Any cavity tray should follow the roof profile. A purely horizontally tray leaves a section of wall between it and any angled roof, and that is susceptible to water penetration.

Clearly the builder's of your estate did not know how to build properly, and managers weren't bothered with quality.

BTW, if you come to sell at some time, and a clued up surveyor sees any window or roof like that without weep holes above, then that's an immediate red mark in the report.
Thanks very much for the helpful advice. Needless to say my surveyor did not pick this up...
 

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