In our "extension + refurb" of our solid brick end terrace we've insulated everywhere (loft, underfloor, cavity walls of block and brick extension, EWI where possible to solid wall, IWI where not possible).

For the IWI we've used mostly 75mm celotex, but on a couple of walls where we don't have space we've used aerogel - the type laminated to a magnesium silicate board either 49mm (40mm aerogel + 9mm board; on the internal face of an external wall of an alcove where the window is < 50mm from the wall - we're already cutting into the architrave a bit here) or 29mm (on the wall overlapping the EWI and on the chimney breasts which project into the rooms, both to avoid cold bridging. The chimney breasts will be filled with more insulation, either surrounding the flue or completely filled).

My problem is that our inspector from Building Control has never heard of aerogel and has asked for BBA certificate etc... This was a bit of a shock to me, given that I thought aerogel was a pretty much accepted product (i.e. appears on energy savings trust publication CE71 as amongst the 'highest performance' insulation materials). I have asked the manufacturers to email the data to building control, but they have been a bit slow about doing so.

What happens if building control won't sign off the use of aerogel insulation in these fews areas where celotex would have been impossible? Am I looking at a huge expense of having it removed?

It's not the Proctor Spacetherm product. It's Magnaline superslim from enviroformsolutions.

The aerogel bit of the product is the same as in the proctor product (multiples of 10mm aerogel blanket), but it is fixed to a magnesium silicate board rather than a fermcell or plasterboard or plasterboard and ply board as in the proctor product.

I've been asked about BBA certification, rather than BRE certification. I'm not sure if this is a statutory requirement (i.e. if it doesn't have it, then the stuff is an automatic fail) or if it's particular to my BC inspector to demand it. I know DamonHD has used Magnaline superslim as he's blogged about it, but possibly not in a context where it requires BC approval.

If the 'aerogel' bit is certified, does it matter what board it's on? (i.e. can I use the fact that aerogel has third party certification, albeit laminated to a different board). The insulation layer is the very same stuff.

What can they do to me if I can't get the necessary certificates.....could I argue that celotex unreasonable for those applications and therefore it's a choice between aerogel and nothing.

Given that any number of people build an extension and put in NO insulation in the non-extended part of the building (and current government has just shot down suggestion that anyone be forced to do anything in this regard), it is pretty galling to be penalised for putting in one of the highest performing (and most expensive) insulations on the market. I'm feeling a bit at the 'end of tether' about it.

weeeell... you could certainly argue on the 'practical or technical' get-out clauses in L1B that it was not possible to achieve 0.3, but then I think what they'd want would be to see what you could achieve with a lesser thickness *of an approved insulant*. I agree it does seem a too-technical technicality.

It's tricky if your supplier is being slow with the tech info. If you can get it, even if it does not amount to full 3rd party certification, you could try presenting it to the BCO, but I failed when I tried it with some sheep's wool and recyc fibre insulation.

Damon, I hoped you'd come in! I fully agree with what you say, but unfortunately some LABCOs will simply refuse insulants without 3rd pty certs, however good they are. I hope that JTG's will bend with a bit of tech data, but (as with my LA) it is not guaranteed.

I will talk to any prospective new buyer for you, clearly you have done a great job, shame about the inspector, sack him!

After my run ins with our local authority Building inspectors I would only use a private one in future, not saying they are all bad just that I seem to get the bad ones.

Can't you just pay for your own BC these days, eg the equiv of Part P? You simply find one who understands aerogel and other 21st century miracles (electricity, squirty foam, etc, too).

Else of course you may gently enquire as to the appeals process against subjective judgements ... independent tribunal ... judicial review ... etc etc... I have twice found now that going to the LA's legal dept and saying "I'd really like to do this the proper way and avoid wasting both our monies getting it overturned in the courts, can you help..." has been effective. If you're not doing anything outrageously wrong there's no reason that the LA should expect other than to lose expensively if they're making unreasonable judgements that cost you time and money...

Rgds

Damon

Google found..

http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7850

Author DamonHD CommentTimeSep 24th 2011
Hi,

I think I'm not out of order here quoting from and email today from John of Enviroform Solutions about fixing my new 30mm-aerogel-backed magnesium board:

"The fixings we recommend are from Twistfix and are from their Insofast range. We use ISF 35s. The 35 relating to the diameter of the domed head of the fixing and they are 105mm long. When we submitted the MagnaLine SuperSlim data to the BRE for them to run them through the BREDEM program the difference in thermal conductivity once the fixings were introduced was marginally less than a milliwatt. ...snip...

I bet he's only carrying out a tick box exercise, so I'd print out the BRE certificate for Proctor 'Spacetherm' product and give him a copy and say nowt !!

Aerogel Spaceloft, the brand used for construction by all the suppliers in the UK received a full ETA (European Technical Approval) last year. I think that should keep him happy.
"The BBA has been designated by the UK Government to issue European Technical Approvals (ETAs) and to represent the UK in the European Organisation for Technical Approvals (EOTA)."

Here is the ETA

http://www.eota.be/pages/valideta/detail.aspx?uid=8f3063eb-9ff6-48e0-9188-53ae7ed26480

ETA - 11/0471

Stop knocking Local Authority Building Control, they dont write the requlations. It would appear that most people are advocating the use of unregistered and untested products. The BBA certificate process has been around for years.

How may people have made their views about Building Regulations known thrrough the recent part L consulation??

Approved Document Part L has a section 3.13 on materials. Annoyingly I can't cut and paste the section. It says

You may show that you have complied with regulation 7 in a number of ways. These include demonstrating the appropriate use of"

"A product bearing CE Marking in accordance with the Construction products Directive (list of directives)"
or
"A product complying with an appropriate technical specification (as defined in those Directives mentioned above"
or
"A British Standard or alternative national technical Standard of a member state.."
or
"a product covered by a national or European certificate issued by a European Technical Approval body"

Presumable the latter includes a BBA/BRE or simlar.

Lots more words in that section that may provide a get out of jail card. Finding hot box tests might be enough?