BC approval for adding partial insulation to walls

[RobertL]

i've had various bits of building work done on my house, mostly consisting of moving a stud wall and fitting a bathroom. The builder the didn't put in a building notice (a misunderstanding) and now the BCO wants me to make a regularisation application for the works.

Most of the work is straightforward and the BCO has actually had a look at the bathroom and informally said it will be OK. But we have also added some thermaboard insulation to the inside of some of the external walls which the has not been told about, although he knew we were considering doing so.

Beefore I put this insulation formally on the regularistion I want to know what the position is. In some places the added thermaboard is not thick enough to bring the (solid) walls up to modern insulation requirements, but it is clear better than doing nothing (that's why I did it). There was no change to the wall other than adding the thermaboard.

Any opinions folks? I'd like it regularised. On the other hand I don't want the BCO to say "you must either add insulation enough for full modern building regs or add none at all". The reason the insulation is thin (30mm) is that there is not room to fit more because of the position of the door frame on the adjacent wall.

thank you,

Robert

[geraldthehamster]

Robert, see Table A1 in Appendix A of Approved Document L1B

're looking at "Renewal of intenral finish to external wall or applying a finish for the first time".

I'd say whether you have problems or not will depend on whether your BCO is helpful or a jobsworth. Or whether you mention it ;-)

Cheers Richard

[RobertL]

Thank you Richard, this is very helpful.

it does seem from the document you linked to that if I add insulation to a wall then I must put enough to bring the insulation up to modern levels. In my case justifications for doing less seem to be "would reduce floor area by more than 5%" and "door frame gets in the way" . So I hope they will eb accepted.

Another interesting example is where I have battened out an alcove to make it the same depth as another alcove. Although this was not done to reduce the heat loss, it will have that effect to a ssmall extent. I'll see what the BCO says about that. In principle he could take a dislike to it I suppose.

Robert

[geraldthehamster]

In principle you could stop worrying, and telling him so much ;-)

Cheers Richard

[dennis]

8<

Unless you have peed off the building inspector he is unlikely to complain that a "repair" is better than the original. If it were new build ne would almost certainly complain.

[Man at B&Q]

Such stupid rules are best ignored. In the face of such stupidity it won't be long before someone takes account of the (tiny) insulating effect of wallpaper on a previously unpapered wall.

MBQ

[The Natural Philosopher]

The key used to be that if you undertook a 'material alteration' the 'material' part of it had to be to modern standards.

Which is a good intention,..if you are upgrading, do it properly .

However if you get a jobsworth BCO, and there are a few, though not as many as you might think - then the definition of what is a material alteration is open to question.

BCO's round here have been content that a refurb left the place at least better regulation-wise than it was.

I think in these cases it is best to adopt one of two positions.

One is simply do it and don't say anything, and the other is talk to the BCO before you do anything, and be guided entirely by his viewpoint.

Anything else is likely to be a fall between stools, and the worst of all possible approaches IME.

[PeterC]

I was thinking that - there's a paint that has tiny insulating beads in it (can't have much effect in a coat of paint), so that would be even worse than wallpaper - the BCO would want 3 dozen coats.

[RobertL]

yes, unfortuneately that is the situation. I thought the builder had put in a building notice but he hadn't. So, the work has been done and the BCO wants a regularisation application.

It raises another point. It looks as if I have to pay =A3120 fee for each wall I have insulated. In some cases the insulated area was only a few square metres so the fee is the biggest cost and probably makes it uneconomic to insulate.

Robert

[Man at B&Q]

Agreed, it's a good aspiration to bring things to the latest regs or even beyond, but it's a stupid rule if it says everything has to be that way, rather than just saying don't make it any worse and don't make just a bit better.

MBQ

[geraldthehamster]

I think the key criteria for whether to involve the powers that be are:

1. Is the work the sort of thing you'd need to mention when selling the house, and for which a potential house-buyer's conveyancer would want to see a certificate?

Anything significant and structural would be; something like a refurbished bathroom, probably not.

1. Is anyone likely to notice that you've done it?

"Yes" if you can see it from the street ;-)

1. Am I competent?

For example, you might want a structural engineer to confirm that a wall you intended to remove was not load bearing. I would, anyway ;-)

It's certainly the case that once you've got Building Control involved you're likely to have issues over what is and is not in scope, although given the right BCO these can often be resolved satisfactorily. Mine is quite helpful.

Cheers Richard

[geraldthehamster]

Can I ask who involved Building Control, and what were the notifiable aspects of your job? Someone will correct me if I'm wrong, but I don't think moving a stud wall would be notifiable. Zone 1 or 2 wiring would be, and we've established that adding a layer to the thermal element would be. But that's all theoretical until you actually make the phone call.

Don't get me wrong, I'm not against BC approval per se - it's just that this occasion seems to have the potential to cause you both increased costs and a colder bathroom!

You are where you are, so can you either do the insulation and hope the issue doesn't arise, or add it later as part of the decorating, after the BCO has left? He (or she) is not going to want to see it decorated, just (in my limited experience) ready for decoration.

Cheers Richard Cheers Richard

[Hugo Nebula]

On Wed, 29 Jul 2009 01:34:34 -0700 (PDT), a certain chimpanzee, RobertL randomly hit the keyboard and produced:

If you've 'renovated' the plaster to a wall, then you should insulate it to achieve a U-value of 0.35W/m²K. It's not a case of all or nothing; the nothing isn't an option.

Check w/ the insulation board manufacturer to see if it will achieve the U-value. If not, I'd leave it off the regularisation unless the BCO picks it up, on the basis of, "don't ask, don't tell". Sometimes the best bit of kit a BCO can have is a pair of blinkers.

[fred]

In article , Hugo Nebula writes

Is there latitude for conservation of original ornate features?

In my case I have some deep ornate cornicing which dictates exactly where the finished wall surface must be. I had hoped to gain extra insulation on some external walls by stripping the original lath and plaster back to the stonework then re-building with 25mm or so Celotex and 12mm PB in the available space, bringing the finished surface back to meet the original cornice.

It'd be a shame to forgo the insulation just to avoid BC problems.

I'm sure I'd do it anyway on the QT but I could get caught.

[RobertL]

Ah yes, but I renovated nothing and replaced nothing. I simply added the insulation on top of the old wall without altering the old wall in any way. the forms ask me if I have "replaced" something.

According to this (which someone higher up suggested)

is some lattitude based on the presence of fixed features. Also, as i read it, you can stop when the insulation removes 5% of the floor area. But i need to read it carefully to be sure exactly what it says.

Robert

[RobertL]

We have another room where I would like to add sound insulation in the alcoves but what stops me is the cornice. The acoustic insulation takes about 150mm depth so it cannot be fitted 'into' the wall as you are considering. I had thought of making rubber moulds of the cornice and then casting a copy onto the ceiling one the acoustic insulation is in. This would presverve the original cornice underneath apart from damage where the 'mitred' corner goes.

Robert

[fred]

Rubber moulds is exactly how the expert plaster restoration people work but getting them in would be serious money. For a non expert, I think that it would be a very time intensive job with no guarantee of success. The alternative of trying to remove and re-fit the existing cornice would probably end in tears.

Difficult choices.

[george (dicegeorge)]

I'm doing similar.I have lots of seconds of kingspan, but perhaps where the plaster was thin I will use an insulator which is thinner but more efficient and much more expensive than bog standard kingspan.

I'v also been sawing cornice down with a woodsaw... which sort of works.. another thread needed?

[g]

[RobertL]

Also you hit the problem that was discussed above: if you don't use enough insulation to make the wall have a U

[RobertL]

What the L1B regs seem to say is that, if you do something new (or renovate) then you must do the work to modern regs. But that you can do things that reduce the insulation (like adding a window) provided to do something somehwere else to compensate. the net effect must be to reduce the carbon footprint.

This is very significant for us. We want to create a huge glass dorrway across the back of the house. This will reduce the insulation. However, the house currently has no loft insulation so we should be able to balance one against the other. If we had rushed in and 'did' the loft at the beginning we would have lost the ability to use it to offset the windows.

Robert