Leaking roof and builder not interested

[Forthelovagod]

I had an extension built 9 yrs ago. Has had water ingress 7 yrs. Builder has said over and over its the chimney stack. Chimney stack is part of original house which is dry. Extension built against chimney stack and so if builder correct about the ingress coming in the stack (not convinced as other opinions vary) why on earth would he build an extension relying on the integrity of the 1930s chimney stack. Why is it not wind and water tight as a seperate entity and butted against the old building. It just seems crazy to me. Fwiw i did ask at time of build of chimney should be removed but was told it could cause dampness.... The irony... Water literally drips in like a leaky tap
The local council building standards guy said sounds like quality of workmanship issue and i am going to pursue this but wondered if anyone with building knowledge could give their opinion. Would it be reasonable to build an extension relying on the integrity of the old chimney stack?

Post some pictures of the offending chimney and extension roof.
What remedial work have you had carried out on the chimney? Has it been repointed and capped or a water tight vent installed?

The chimney stack was reharled before the extension was built. Both pots capped but vented. Never any ingress into original house, still no ingress there only on extension side.

So an external Chimney?

Best guess work as no pictures...... If its leaking around the chimney, then it does sound like he has messed up the flashing that should prevent water ingress via chimney/roof material.

Either way, Imho You should get another builder in asap, you'll get nowhere with your original builder, esp after 9 years, all you'll do is add stress and worry/delay to your life as well as the legal costs....and why would you want a builder fixing it who you ve lost confidence in?

7 years is plenty of time to damage the structure of your extension, so get it fixed by someone who knows what they doing.

My only concern is why did it remain leak free for the first 2 years?

Hard to show it well but these are photos from when they pyt some flashband on to try and stop the ingress

I dont think it was necessarily leak free for first 2 years but i think it took two winters for the staining to be apparent

So how far up does the flashing go up under what looks like the original roof slates or is that a slated wall?

The water cannot get through your metal roof, so the water is either coming through/around the chimney flashing or the flashing used along the original slate work.

Capillary action can make the leak look like it is at point A where as its actually somewhere else and water can track a long way and as that looks like a very shallow pitch, water can easily get blown and find its way in to your house.

that flashbanding is a complete bodge.

As i said, you do really need to get a skilled roofer to look at this, not a general builder.

It's not going to be the chimney stack if it was sound for the 80 years prior to the builder touching it.

What it will be is water ingress in the roof he's fitted.

Get another builder in who specialises in flat roofs.

Looking at your pictures I think adding some seals might help, it might be just one area that's compromised and the resulting water can be blown in.

Either way, abandon the original builder and get a roof specialist in.

The roofer and the builder have both been out. The builder is the most reputable one around, we went with him to get a good job despite being almost 10k more than the other quotes. Flashing goes a fair way under the slates. The water appears to be coming in around the chimney but it's unclear why/where/what/who is responsible. All i know is it cost me my life savings and is not fit for purpose.
Found a photo the builder took to show where he thinks its coming in and why he thinks its not his problem. This is infront of the chimney stack under the new tin roof as builder lifted it off to investigate.

Well, tbf to him, the chimney was outside the interior of the house prior to the extension, so if it was failing, would you have noticed? as i believe you said, there is no leaks inside the original structure.

i suspect or rather my partner does, is that the problem is in the original slated part of your house, water is getting higher up and running in under the chimney flashing and or the flashing for the extension roof....it could be a very cheap fix.

This assumes the chimney is/was properly pointed up prior to the extension and not just skimmed over.

He has taken on responsibility to build a fit for purpose extension for you, so he should have fixed the chimney to ensure this.

The problem you have is its 9 years since the original build, if you can afford it, you have to go elsewhere to get this fixed or it will cost you even more in the long run.

Thanks for the reply @GPTec1 the thing is ive been in touch with him since the water ingress became apparent within the first 2 yrs of being built so i do feel he should be putting it right. With the amount of energy he has put into proving its not his problem im pretty sure he would have been quicker fixing it