Cold bridge at new patio doors – sill resting on brickwork? Installer says “nothing more can be done”

[saveasteading]

It's been interesting to follow how strongly you are making this argument.

I think you are wrong, and have even started sympathising with the other party.

Reasonable care is judged by what skills they may be expected to have. In this case that would not apply to knowing all the building regs, esp as they apply to an existing property, and whether they are expected to write a long list of exclusions.

But the credit card company may decide on some other logic.

So I've no more to say.

[fandyman]

2 hours ago, saveasteading said:

It's been interesting to follow how strongly you are making this argument.

I think you are wrong, and have even started sympathising with the other party.

Reasonable care is judged by what skills they may be expected to have. In this case that would not apply to knowing all the building regs, esp as they apply to an existing property, and whether they are expected to write a long list of exclusions.

But the credit card company may decide on some other logic.

So I've no more to say.

That’s fair - we’re clearly coming at this from different perspectives.

Where I disagree is that reasonable care is limited only to what a trade chooses to concern itself with. It’s judged on the service actually provided and the outcome it creates, not on whether the installer considers certain aspects “out of scope”. I’m not expecting encyclopaedic knowledge of building regulations or retrofit design - I’m questioning whether an installation outcome that produces persistent condensation and mould under normal conditions is an acceptable result of the service supplied.

You’re right that the credit card provider may apply its own logic - which is precisely why I’m comfortable letting an independent process assess it rather than relying on forum consensus. At that point it becomes an evidence-based decision, not a matter of sympathy either way.

I appreciate the discussion - I think we’ve probably taken it as far as it can usefully go here.

[SBMS]

1 hour ago, fandyman said:

That’s fair - we’re clearly coming at this from different perspectives.

Where I disagree is that reasonable care is limited only to what a trade chooses to concern itself with. It’s judged on the service actually provided and the outcome it creates, not on whether the installer considers certain aspects “out of scope”. I’m not expecting encyclopaedic knowledge of building regulations or retrofit design - I’m questioning whether an installation outcome that produces persistent condensation and mould under normal conditions is an acceptable result of the service supplied.

You’re right that the credit card provider may apply its own logic - which is precisely why I’m comfortable letting an independent process assess it rather than relying on forum consensus. At that point it becomes an evidence-based decision, not a matter of sympathy either way.

I appreciate the discussion - I think we’ve probably taken it as far as it can usefully go here.

To round it off maybe.. I think your position is intellectually coherent, but a section 75 claim is not a forum for debating where industry responsibility ought to sit. It is about whether the installer breached their contractual duty as one would normally understand it.

 

It isn’t about whether the outcome is subjectively unacceptable, it’s about whether the installer failed to exercise reasonable care and skill in the service they actually provided. Notwithstanding the issue with poor sealing (which is unlikely to be the condensation root cause), In practice they’ll look at whether the door was installed correctly and in line with manufacturer guidance, and whether the opening and threshold construction were part of the installer’s scope or pre-existing building fabric.

 

Your industry expert will look at whether a competent door installer should have identified the sub-threshold detail as unacceptable and either refused to install or required a thermally broken support.  You’ve actually heard from a number of very experienced builders on here, a structural engineer or two and an actual industry expert that runs a door installation company. Whilst many have sympathised with you, none have agreed with your assertion and I think it likely that your industry expert will not find in your favour. I think it’s quite likely they’ll conclude the condensation risk arises from the underlying construction rather than a breach by the installer.

 

It is though, a fairly low risk approach for you to take.  Good luck and I am sure we would all be keen to hear back from you on the outcome. 

Edited yesterday at 21:22 by SBMS

[fandyman]

1 hour ago, SBMS said:

To round it off maybe.. I think your position is intellectually coherent, but a section 75 claim is not a forum for debating where industry responsibility ought to sit. It is about whether the installer breached their contractual duty as one would normally understand it.

 

It isn’t about whether the outcome is subjectively unacceptable, it’s about whether the installer failed to exercise reasonable care and skill in the service they actually provided. Notwithstanding the issue with poor sealing (which is unlikely to be the condensation root cause), In practice they’ll look at whether the door was installed correctly and in line with manufacturer guidance, and whether the opening and threshold construction were part of the installer’s scope or pre-existing building fabric.

 

Your industry expert will look at whether a competent door installer should have identified the sub-threshold detail as unacceptable and either refused to install or required a thermally broken support.  You’ve actually heard from a number of very experienced builders on here, a structural engineer or two and an actual industry expert that runs a door installation company. Whilst many have sympathised with you, none have agreed with your assertion and I think it likely that your industry expert will not find in your favour. I think it’s quite likely they’ll conclude the condensation risk arises from the underlying construction rather than a breach by the installer.

 

It is though, a fairly low risk approach for you to take.  Good luck and I am sure we would all be keen to hear back from you on the outcome. 

I think we’re actually closer in position than it might appear - though perhaps drawing different conclusions from it.

You’re right that Section 75 isn’t a forum for debating where industry responsibility ought to sit. That’s precisely why I’m not relying on what is customary, typical, or widely tolerated in the trade, but instead on independent assessment of whether the actual outcome of the service supplied meets the standard of reasonable care and skill.

Where I part company is the suggestion that persistent condensation and mould are merely “subjectively unacceptable”. These are objectively observable outcomes, not matters of taste, and they are exactly the kinds of issues that reasonable care and skill are meant to prevent - regardless of how common a particular installation detail may be.

You’re also right that an expert will examine whether a competent installer should have identified the sub-threshold detail and either mitigated it or flagged it before installation. That question sits at the heart of the dispute, which is why speculation about how often this is overlooked in practice doesn’t really resolve it.

I appreciate the confidence expressed about how an expert might conclude. I’m comfortable letting evidence rather than expectation decide that point. If the conclusion is that the underlying fabric alone is responsible, I’ll accept it. If not, responsibility will follow accordingly.

Either way, I agree - it will be interesting to see the outcome, and I’m happy to report back once it’s determined.

Edited yesterday at 22:22 by fandyman

[Spinny]

Can I add in another consideration.

From what you have described the complete window/door consists of multiple individual parts: The two fixed side windows with their own frame (presumably pre glazed with double glazing units), the central doors with their frame, and the cill piece itself which the other parts sit onto as a base.

 

Have you carefully checked the vertical and horizontal alignment of these different parts ? If for example the two side windows were fitted to the outer edges of the opening first, but the inner vertical frame edge ended up not being perfectly vertical, then fitting the door frame vertically against it would become a problem. Quite possibly a fitter might then choose to then fit the door frame perfectly vertical regardless. So there would then be a variable gap between the side frame and the door frame - quite possibly tight at the top, but with an increasing gap near the base. This could then be filled with mastic/sealant and appear normal. However there could be an uninsulated gap or path left between the fixed windows and the door frame at the lower part - thereby causing cold bridging problems.

 

In a similar way there could be misalignment and gaps occurring between the cill and the window and door parts fitted onto the cill - again possibly leading to cold gaps between the cill and frame possibly hidden by sealant.

 

I have to say it is a skilled and potentially time consuming task to assemble frames into an opening with precision such that all the verticals are spot on plumb and all the horizontals are spot on plumb level. Doors especially need to be true so they don't swing open/closed of their own accord etc and meet correctly when closed.

 

Anything other than expensive spirit levels are unreliable and can easily be out. Small alignment errors which many tradies might think 'good enough lets go down the pub' might mean installation gaps at the lower part of the frame and between cill and frames.

 

I might be barking up the wrong tree, but get yourself a long expensive known accurate spirit level (or plumb line) and carefully examine whether all the parts of the installation are properly plumb and tightly joined to one another.

 

(It took a second fitting visit to get our alu bifolds right and they sent their crack fitters that were at it until 7pm getting it all just so. And I imagine UPVC frames may show more bendability than aluminium.)

 

 

[Spinny]

Also that heat camera is showing the coldest strips at the bottom edge of the double glazed units i.e. just above the bottom frame where the glazing starts.

 

Could it be that the double glazed units were not a good tight fit into the frame itself, so that you actually have cold air finding it's way through the windows/doors themselves - underneath the base of the double glazed unit - i/e/ between upvc frame and DG unit.

 

Window companies may be ordering in ready made dg units to fit into their frames. They will NOT want the glass to end up too big, so it would seem quite possible for the dg unit to end up on the small size sometimes and perhaps not to fit tightly ?

Also there are usually seals between the glass and the frame - are these tightly fitting ?

 

I think it is usual to have a little lee way for heel/toe adjustments, but ultimately the entire door assembly should be perfectly air tight on both sides. If you fart outside you should not notice it inside :0). Maybe you could try some sort of smoke test ?

 

(In my youth I once had to travel around with a fire service chap for a few days as part of a business analysis - the height of his entertainment was taking out a phallic shaped smoke machine which hummed and emitted smoke from the tip to test the smokes. For some reason he thought it amusing to test the smokes in the headmistress office when visiting the girls schools ?!@)

 

[Spinny]

Go to ChatGPT and type in...

"Is it possible for cold air to pass through a double glazed door or window by passing around the sealed double glazed unit i.e. between this unit and the frame it is fitted into ?"

 

When Chat GPT answers and then asks you the frame type etc type in,,,

"a upvc frame which has been fitted a few weeks ago and comprises of a french door fitted between 2 outer fixed glazed windows"

 

(And the first 2/3 minutes of this video may be of interest...

https://youtu.be/rc5DutkQ0WM

Edited 3 hours ago by Spinny