Inadequate insulation in loft conversion?

[DumbBlonde5]

We had our loft converted a year ago and weren't that happy with the builder but had no reason to suspect an issue with insulation. The loft had planning and buildings regs and the building inspector signed off the insulation.

Our first winter in there (it's a master bedroom for us) has been awful as it's absolutely freezing. We thought at first it was the trickle vents as we've not had these before and they do let cold air in. The windows were fitted by a company who did the rest of our house that we know and trust so we have no concerns with the windows themselves or fitting. We struggle to keep the loft above 15 degrees. We heat the loft up ok but as soon as we turn heating off the heat will go. Overnight it's bitter. We shut all the trickle vents but it's still freezing.

I assume this doesn't sound right? We are going to pay for a thermal survey to see what they show. If this comes back with inadequate who is liable? Buildings regs for signing it off or the builder?

I saw the big foam insulation during the build but some of the bits looked like there were chunks out of them. I never saw them tape this, just put it between the wood. They also used normal plasterboard not insulated. Not sure if this is relevant,

We have carpet fitted, fitted furniture and had it professionally decorated so I also can't see a way to fix issues without ruining all of this and we don't have the funds to redo them.

Any advice/knowledge appreciated please.

 

[motorbiking]

Building control has no liability unless they failed in duty to inspect. Its possible that some of the insulation has slipped down or that you have a thermal bridge (some high conductor not being properly packed in insulation. e.g. a steel joist.

A thermal survey is no better than you doing a thermal map with an infrared heat sensor gun that can be purchased for £30.

Essentially you heat your room and scan 6 inches or so apart and map the temp. Where you see different temps you have suspect areas. As the heat drops in the room keep testing. This will give you an indication where the problem is. You can then explore what to do.

If you find lots of cold spots then its probably that the insulation was installed with gaps and not properly taped, if its just one area then it could be simple to fix with foam.

Some pics will help.

 

[oldbutnotdead]

Is there any insulation in the floor (left from when it was the loft- not a good thing cos it means you don't benefit from rising heat in the house)? Or any draughts under the floor?

 

[tony1851]

Sounds like there's just insufficient insulation; 15º is not acceptable for a bedroom.

If you have a flat-roof dormer, you'd need a total of around 150mm thickness of foil-faced board in the roof (usually 100mm between the joists and 50 mm underneath, with taped joints) going by the regs in force 12 months ago.

The sloping roof at the front is likely to have less than this thickness.

If the joints haven't been taped with the aluminium tape before plasterboarding, its possible you may get condensation stains on the ceiling at some stage.
If there are low walls near the eaves, its possible they've not been insulated adequately.
What thickness of insulation did your plans show? Assuming you had plans drawn?
As regards any liability, forget Building Control. They are not quality control inspectors and they can't check everything and may miss some things (as MoT inspectors often do on cars).
Good luck sorting this out.

 

[DumbBlonde5]

Is there any insulation in the floor (left from when it was the loft- not a good thing cos it means you don't benefit from rising heat in the house)? Or any draughts under the floor?

There is the original loft insulation and then he topped it up a little but I wouldn't say it's fantastic. I don't know if there are draughts under the floor as it's now covered with cloud 9 underlay and carpet. There are draughts but they feel higher up which is why we thought it was the trickle vents initially.

 

[DumbBlonde5]

Building control has no liability unless they failed in duty to inspect. Its possible that some of the insulation has slipped down or that you have a thermal bridge (some high conductor not being properly packed in insulation. e.g. a steel joist.

A thermal survey is no better than you doing a thermal map with an infrared heat sensor gun that can be purchased for £30.

Essentially you heat your room and scan 6 inches or so apart and map the temp. Where you see different temps you have suspect areas. As the heat drops in the room keep testing. This will give you an indication where the problem is. You can then explore what to do.

If you find lots of cold spots then its probably that the insulation was installed with gaps and not properly taped, if its just one area then it could be simple to fix with foam.

Some pics will help.

I have looked at these but there are so many. Any thoughts on which one you would recommend please?

Also we thought a survey would give a written report from an independent source if we needed to take legal action against the builder for any issue. Maybe worth using our own gun first though.

 

[DumbBlonde5]

Sounds like there's just insufficient insulation; 15º is not acceptable for a bedroom.

If you have a flat-roof dormer, you'd need a total of around 150mm thickness of foil-faced board in the roof (usually 100mm between the joists and 50 mm underneath, with taped joints) going by the regs in force 12 months ago.

The sloping roof at the front is likely to have less than this thickness.

If the joints haven't been taped with the aluminium tape before plasterboarding, its possible you may get condensation stains on the ceiling at some stage.
If there are low walls near the eaves, its possible they've not been insulated adequately.
What thickness of insulation did your plans show? Assuming you had plans drawn?
As regards any liability, forget Building Control. They are not quality control inspectors and they can't check everything and may miss some things (as MoT inspectors often do on cars).
Good luck sorting this out.

Yes we had plans and structural drawing but the builder kept complaining about them saying he had to change things and not to worry. The same builder did this with our friend's loft too even though they had their plans drawn up by a different person. We have a large flat roof dormer at the back and I saw the huge thick foam for the roof of that.

 

[jeds]

Did you take photos of the work during the build. Maybe there are some that show the insulation?

Do you suspect that the insulation is undersize, or that there may be large areas missing?

PS. what insulation was specified on your drawings?

 

[oldbutnotdead]

The underfloor insulation is doing you no favours.
As for draughts in the room- have a go with a smokey candle around the walls, windows etc but it's quite likely the draughts are just warm air that has been cooled by contact with cold walls/ceilings.
If the PIR board joints weren't taped you are potentially losing much of their thermal performance due to cold air whistling round, especially if there's a void between the insulation and the pb.
Pics of the build in progress would be very useful to determine what you've actually got.
Without pics, or other definitive evidence that your builder has significantly deviated from plans and good practise, you're unlikely to get anywhere by chasing him.
Start logging some data - easiest way is invest in some cheap usb temperature loggers. One for outside, one for inside, one for the radiator. Set them to sample hourly & you'll build some useful info about the thermal performance of the room.
When (if) the weather improves you'll probably have to remove a couple of sheets of plasterboard so you can see what's actually behind them.
If you find there's insufficient thickness of insulation and gaps all over the place you will then be in a better position to decide what to do.

 

[jeds]

If the problem is missing insulation it will show quite easily with a thermal camera. Personally I have found cheap ones to be a waste of time so I hire them for surveys at about sixty quid a day. You get a decent quality camera, with decent resolution, that will show gaps in insulation quite clearly. It's more of a problem if it is under-rated insulation because only the really expensive cameras have sufficient sensitivity to measure and report accurate difference between 100mm and 140mm.

 

[oldbutnotdead]

If the problem is missing insulation it will show quite easily with a thermal camera. Personally I have found cheap ones to be a waste of time so I hire them for surveys at about sixty quid a day. You get a decent quality camera, with decent resolution, that will show gaps in insulation quite clearly. It's more of a problem if it is under-rated insulation because only the really expensive cameras have sufficient sensitivity to measure and report accurate difference between 100mm and 140mm.

Didn't realise they were that good- that'll be an excellent start, far cheaper than pulling boards off

 

[DumbBlonde5]

 

[DumbBlonde5]

Some photos of the work above. Normal plasterboard (not insulated) was placed on top and then skimmed.

 

[oldbutnotdead]

All those joints (board to timber and board to board) should have been taped if there was no over the timber cover sheet. Not just to prevent draughts but also as a vcl.
If those timbers are 4 x 2 (they look like it) there's max 100mm of insulation in the walls- that's adequate inside a solid brick wall but if the outside of the dormer is only cladding or something like then possibly not.
Looks as if there's 50mm under the rafters but can't see if there's anything between them.
Get that thermal camera going.....

 

[DumbBlonde5]

All those joints (board to timber and board to board) should have been taped if there was no over the timber cover sheet. Not just to prevent draughts but also as a vcl.
If those timbers are 4 x 2 (they look like it) there's max 100mm of insulation in the walls- that's adequate inside a solid brick wall but if the outside of the dormer is only cladding or something like then possibly not.
Looks as if there's 50mm under the rafters but can't see if there's anything between them.
Get that thermal camera going.....

The small front dormers have cladding using our old roof tiles. The rear dormer is also tiles but new. The walls seem thin as all our windowsills are very shallow and you can't place anything on them due to it.