Renovation blunder

We had new doors fitted and a suggestion was made to flatten the threshold on one door to which we agreed. This has not worked out. The aluminium threshold is a great heat conductor and we get condensation on it in addition to the rubber seal that occasionally shifts in the closed position forming a permanent air vent.
How to insulate the aluminium?

I regret to say that you probably need to change your threshold, both from the insulation and draught proofing perspectives.

How easily can you cut out a groove below the threshold to its full width and to a depth of 150mm or to the DPC, whichever is the lesser?

Then into the new void fix Compacfoam

Also from the same website:

You could start by comparing the thermal and airtightness characteristics of your new door and frame with the advertised details. If, as I suspect, there is a big discrepancy then you could have recourse to the installer/manufacturer.
Over 35 years ago I had an aluminium door set installed that was thermally broken. I would have hoped for some improvements by now not regressions.

I was just about to ask a similar question. Our front door, fitted about 5 years ago, sits on top of the original quarry tiles. While the door works fine we have noticed that the tiles are a thermal bridge and condensation is wetting the carpet.

Does any one have any thoughts on how to address this without having to rip out a very expensive hardwood door.

It should be possible to remove the door from the frame and the frame from the wall unless you have rendered/plastered after it was fitted. You can then address the insulation (as described above) before refixing the frame and making airtight before fixing the door.

Shame you have a problem Lloyd, but thanks for alerting others to a potential problem. My french windows into the garden have been a trip hazard ever since installed, and when I get round to replacing them I’ll be insisting on a level threshold for age-friendly reasons, so the comments and replies are very helpful.

@Tim- I had not thought of going this route but it is a primary option. I was thinking of insulating the threshold but this is not a complete solution. Good proposal

Thanks, it’s good to know that I could help. I haven’t done the same job myself but have plans to move my front door and thus improve my form factor. That process will be part of the job. I do know of other retrofit projects where it has worked.

Btw, in solid walled houses you can also insert thin insulation along the sides of the doorway in a similar way.

With cavity walls it can be worth inspecting the cavity and topping up as required. Push on the insulation batts to see whether they are loose and can fill a gap further along. Due to shoddy workmanship there are often gaps between insulation batts.
Do this when replacing windows too.

Edit: check that you don’t have loose fill insulation before opening the cavity!

Pipes- The standard is copper- should I replace with plastic as this would cause less condensation issues where pipes run under floors and up exposed external walls?

Leave your copper pipes and insulate them with the lowest U value pipe insulation you can find.