Question about insulation in small pitched roof

I wondered if any roofers could offer advice?

About a year ago I had the 10m2 bathroom roof of my Victorian terrace replaced. We used a recommended contractor who was here for about 3 days. The roof had been leaking and we opted to replace. No problems with workmanship - it was all very professional as far as my untrained eye could see. Most importantly, no more water running down my walls.

Anyway, fast forward to a building regs inspection to another part of the house and the inspector starts asking questions about the bathroom roof. He was most interested in whether the roof space had been insulated while the roof was being replaced (there is no way to get into the roof space from in the inside of the house, the ceiling slopes just like the roof and is plasterboarded up). I check with the roofer and after a brief pause he says 'no it's not'. I asked him why not and he said because insulation would slip and bunch up......

Building inspector consequently goes on to tell me that I am going to have all sorts of problems now with condensation as the job hasn't been done properly. It's certainly very cold in the bathroom in the winter and I guess the heating in that room is disappearing off into the atmosphere but I can see no signs of damp.

Asking about insulation in the roof space never crossed my mind while getting quotes or when the roof was off. I paid the guy (very) well for the best job. I guess the lack of insulation is my responsibility and not the roofer? And now as a result am I likely to have all sorts of problems as the BI has told me I will? He hasn't asked me to rectify anything but I got the impression that he could have if he wasn't in such a good mood!

These might be all obvious questions to folk here but this is my first home. Thanks

PS: According to invoice he removed old slate and replaced with new cement fibre slates on 25mm x 50mm battens and Tyvek breathable felt.

Rip the ceiling down and install 300mm fibreglass (150mm between joists 150mm across). Whilst the ceiling is down, get the b.i. to inspect and confirm that it is indeed breathable membrane. If it turns out to be breathable then you should be ok.

Re-fix the ceiling using 12.5mm foil backed (duplex) plasterboards and skim.

Job done, no worries.

noseall said:

Rip the ceiling down and install 300mm fibreglass (150mm between joists 150mm across). Whilst the ceiling is down, get the b.i. to inspect and confirm that it is indeed breathable membrane. If it turns out to be breathable then you should be ok.

Re-fix the ceiling using 12.5mm foil backed (duplex) plasterboards and skim.

Job done, no worries.

Click to expand...

Thanks noseall. From your answer then I should assume then that yes, condensation is an issue if you don't insulate a roof space?

AuntyVanya said:

Thanks noseall. From your answer then I should assume then that yes, condensation is an issue if you don't insulate a roof space?

Click to expand...

Condensation, in your case will be dealt with via the breathable membrane. The risk of condensation will be higher though because of the lack of insulation at ceiling joist level.

You really need to insulate at ceiling level to get a practical solution. You could fix insulation boards to the exiting ceiling leaving the existing in place, then fix new plasterboards through these. But i have a feeling the insulation thicknesses required would make this method impractical.

I am sure I can get my hands dirty and pull the ceiling down (sob sob). So frustrating that someone so highly recommended has left me in this position though.

Now the million dollar question, is this my fault or the roofer's in your opinion? I didn't specify insulation, but then again I didn't specify slates, battens or membrane either

Should he have fitted insulation without question to conform to regs? If so, I am tempted to ask the roofer to put right.

I dont believe it's his responsibilty at all.. But! the obvious thing to do is report back and advise insulation to you for the go ahead. a bit careless of them

Whenever we carry out work, that say the customer is choosing to keep under the reg's radar so to speak, we always advise carrying out the work to current reg's standards. The customer is simply avoiding shelling out for the inspector.

Illegal i know, but it is a customers responsibility to involve reg's - i can only advise.

To not fit insulation or indeed to not mention it is a professional crime. It is ridiculous to assume that he simply forgot. Whether or not he has a case to answer falls with the fact that you may have wanted the job doing as cheaply as possible and never specified it. This statement may not be true but he could use it a a retort.

......or, he could say that you intended fitting insulated plasterboards at a later date.

I was completely oblivious to the fact that I would need to involve Building Regs on a job like this and it wasn't mentioned to me by the roofer. It was only when the council were inspecting my single storey extension many months later, and started asking questions, that it dawned on me they had a legitimate interest in the roof too.

I appreciate that not investigating the job properly beforehand is my fault - you live and you learn. I doubt I would have a leg to stand on but I am going to call him again to discuss nonetheless as I am really disappointed and cannot understand why he didn't give me the opportunity to insulate when the roof was off. There is no question that it was done on the cheap (I wish lol).

Thanks again for the advice

No prob's A.V. Incidentally, if i am aware that b.c need to be involved i will always advise the customer.