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I’m turning to the STW hive mind for advice on where to turn.
We had a loft conversion carried out two years ago buy a Which? Trusted Trader who turned out to be the most devious, despicable companies I’ve ever had the misfortune to pay a large amount of money to do a half arsed job. Long story short(ish), they did a shocking job, added costs at every opportunity and caused us a huge amount of stress and inconvenience. We thought we’d finally drawn a line under it 18 months ago only for the flat roof to leak over Christmas 2017, causing water to pour into our bathroom on Boxing Day. Another nine months later and they eventually re-laid the roof and we hoped never to have to communicate with them ever again.
We’ve always thought the loft room was very cold, but put it down to it having a large amount of external wallage. However when taking out a light fitting all I can see is a thin layer (20mm max) of foil and wool ‘blanket style’ insulation. A quick google suggests that building regs stipulate a minimum of 270mm fibre/wool, 175mm of rigid board or equivalent to a u value of 0.18W/m2. Buildings consents were granted (by an inspector appointed by the loft convertor).
So my questions are: is this insulation likely to meet building regs? If not where do I turn – presumably the Inspector was complicit and/or incompetent, likewise the loft convertor, but can I expect ether to do anything about it and if so who? Which? were involved as an ombudsman during out initial contractual issues , but were quite frankly more hassle than they were worth – they get paid by the trader to use their Which? Logo on marketing material and offered us minimal support. Is this a job for a lawyer? I can feel my blood pressure rising as I write this. Any advice gratefully received.
Phone your local council Building Control Dept in the morning. In my experience mine have been very helpful.
Very good I values can be achieved using tri iso insulation or similar. Depends where and what they have used.
my first thought reading your post was it could be tri iso like wrightyson mentions. not used it for a long time but its handy where space is limited.
just finished doing a job a couple of weeks ago, building inspector wanted 140mm of kingspan.
tri-iso on it's own won't get the U value, usualy need 50mm Celotex/Kingspan/etc between rafters/joists too.
You'd be best to contact the approved inspector (AI) rather than the local authority. I work for a LA and we'd point you in that direction, but it would be worth asking the LA if the AI has served a completion notice
Thanks all. We have a Final Certificate issued by the AI issued in May this year. We'll get in touch with them first, but as I said they were contracted by the trader. We only managed to get the completion certificate after chasing and chasing ourselves.
From memory the only thing the inspector picked up on was the position of one smoke detector. There is a layer of tri iso (having googled it!), but I cannot recall seeing any riding board kingspan or celotex going in and there certainly isn't any in the storage they put in the eaves - they're draft as hell!
How is the u-valued measured? Does each material come with a rating and they just add up?
Basic silver foil quilt or whatever you want to call it that I'm about to use in lining my summer house/shed is equivalent to 75mm of cellotex. It's u value also differs in how and where you use it.
What did your architect specify?
No architect - the convertor did the designs. Round here (1930s semi's) they often don't even come to the house to quote!
I want to be sure that it conforms to building regs which sound pretty stringent. My confidence in this trader is rock bottom after having to fight to get even basic snagging done. I've learnt a lot through this saga! We're doing a ground floor extension with full architect designs and a personally recommended builder.
Which recommendations are fairly worthless, realise this doesn’t help you but....
The insulation could be a bit of a red herring, but still get it checked regardless. In my experience rooms that are always cold have a leak/hole/gap somewhere, likely candidates are poorly fitted or low quality windows and doors.
Use an online u-value calculator. If of course you can find out what all the layers are and their thicknesses.
Well done for going with an independent architect second time round. 'Designers' working for a contracting company will always have saving money (for the contractor) as their paramount consideration.
Has a warm deck not been installed, would seem odd for a flat roof loft conversion not to have one. We did this in our last house, kingspan in the walls too and always seemed chilly.
If you have got a cold deck, you will get thermal bridging through the joists, not ideal.
The vast majority of dormer roofs are cold deck. They're easy to vent in that situation and don't reduce head room as much as a warm roof. Thermal bridging is accounted for in the u-value calculation. The multi foil under the roof joists would reduce thermal bridging.
Multi foil and 100mm wool would get you pretty close to 0.18. It doesn't sound horrific and not wrong enough to go through the stress of pursuing anyone.
I appreciate that you don't have any faith in the builder but they might have got this bit right.
Chances are the building inspector didn’t visit site or if he did it might only have been once. Much of the “approval” will have been based on the drawings and verbal assurance from the builder to what they actually did (or said they did more likely).
Anecdotally there has been a lot of issues with the non council building inspectors. If you are really concerned then you need a report on the state of the work from an independent inspector then sue the building company and possibly the inspector for any breaches of the specification.. this would involve a fair bit of mess as obviously you need to cut into voids etc to see what is actually there. whether its worth the hassle only you will know
All very useful, thanks all. Yes, as MrSmiff says, I think despite my serious doubts over the quality of their work, I can only hope that the trader has at least met the very minimum standards and it is not worth the inconvenience or stress of pursuing this further.
There is at least some insulation in there and I intend to try and pack out the wind tunnel that is the under-eaves storage. I suspect reducing the draft through there may have a dramatic effect on the overall insulation.
Sparksmcguff - I couldn't agree more. Which? Trusted Trader status was simply used by the trader to draw in business with no assurance of any quality. The trader knew exactly what he could get away with, namely endless verbal assurances but nothing binding ever in writing. Oh how I have learnt from this process!
Our experience would also back up tjagains and rockhopper's suggestions. A private inspector working for the trader is hardly going to bust a gut to spot any failures to meet regs, and once it's all plastered and finished it'd take some commitment to point the finger.