Changing Extension to Bathroom

[roboputt]

We're changing our single story extension at the back of our terraced house, from utility room to bathroom. The old room (and roof) is basically:
External walls: Double cavity brick to half height (dwarf?) and then above that it is cladding on the outside, PVC membrane, some rock wool type insulations and plasterboard. The cavity is 100mm deep with studs that are 100x45.

You step down onto a concrete floor about 8 inches.

I have built a false floor to enable some minor plumbing work, but mainly so you walk run on the same level - using joists and 18mm OSB on top with a view to putting Lino down. I took the opportunity to take a bunch of mineral wool I had left over from the loft and have laid it down as the room is usually pretty cold. I haven't changed any other insulation, and what I have done on the floor is certainly better than what was there, but certainly I haven't touched the roof which - if made today - would need more insulation.

Will building control have an issue with this, or are they ok provided what I have done is at least better than what was there?

Thanks,

R

 

[DAZB]

If BC are involved they will no doubt want it done to the current Regs to achieve the liveable standard of housing. You would need foil backed PIR between the joists and similar to the ceiling and that would certainly be noticably warmer for you in there. Best option is to ring them if you are currently dealing with them and see what they say. If you haven't involved them you could just carry on doing it how you like but you run the risk of problems down the line if, or when, you come to sell the house.

 

[roboputt]

The issue is that the extension was built to building regs several years ago. The insulation is terrible, but the room is tiny. The main issue has always been the concrete floor and so we have simply taken the opportunity to put insulation in as we were lifting the effective floor up 8 inches. We haven't changed the floor, and frankly I used mineral wool left over from my loft.

So I'm a bit resentful that I'm improving something but might be told that simply improving it then triggers it needing new regs.

And the roof is so low that if they tell me to rip out the plasterboard and put new insulation up the project will be toast as with a flat roof that extends over another room I'd have to re-roof the whole thing.

 

[^woody^]

Building regs will not apply.