building regs - insulation

si_man_2

Hi,

We are having an extension built, and the builders have nearly finished the woodwork for the roof. The building regs officer from the local council has insisted that there must be further insulation between the rafters, in addition to the tri iso super 10 insulation that was submitted on the planning application.

This is priced at £2750 + vat. Our building consultant mentioned something about a recent court case?

Any builders/planners know what this court case is? or why this is necessary.

Thanks

adaze

:eek:

We just had Kingspan type insulation between the rafters at 90mm thick, BC were happy with that. Sounds like an absolutely ridiculous amount of money, your not attempting to build an extension the size of terminal 5 are you?

si_man_2

That sounds like common sense. The extension is not that big, but this extra insulation apparently costs £40 a sheet and the sheets are not that big.

We thought the tri iso would be enough, it's very frustrating not to mention expensive!

peediedj

tri iso 10 is a stupid price bought some for a customer at work and they near died when i todl them the price

robv_3

tri iso super 10 is a foil type insulation which has failed the British standard Hot Box Test (BS EN ISO 8990:1996) a number of times. The local building control were advised to use a lower R-Value than the manufacture specified (BR 443) resulting it additional installation being required as per your case.

This went to court and the foil insulation company won the case but it was more on the legality of BR 443 than if they work and the ratings.

On a personal level I've used them a number of times and would NEVER use them in my house unless it was for additional installation over the legal requirements.

robv_3

sheet are 2400 x 1200 and between 30 -> 60 quid a pop depending on the thickness.

Grumps

I've got a similar question but not involving Building Regs.

Daughter (and family) are in a house with a flat roofed kitchen extension. Having removed the 'faux' timbering, the ceiling is in such a mess that it will be easier to drop the lot and replace the plasterboard. I am anticipating that there will be NO insulation above the existing ceiling.

Therefore I will be looking for a 'rigid' product to cut and place between the ceiling timbers.

Any suggestions please? Product name? And will it fit in the car or need to be delivered? Obviously I am mindful to leave an air gap between the top of the insulation and the underside of the roof structure. Judging by the span, I expect the ceiling timbers to be a minimum of 6" x 2".

Thanks.

robv_3

kingspan or celotex. comes in 8x4ft sheet so unless you have a very large car will not fit. Very easy to strap to the roof even without a roof rack as its extremely light. Just make sure the wind does not get underneath it. From memory current building regs need 165mm worth between the joists but you will need to do your own calculations.

You could just stick fibre glass insulation up between the joists.

jennifernil

We have recently insulated using Kingspan, we used 2 x 90mm thicknesses, it was just over £30 per sheet (1200mm x 2400mm). There is a place that sells it very reasonably on-line with free delivery over a certain amount. It could be Planet Insulation or something like that. We bought locally as it was cheaper for our whole order as we had plasterboard too..

maninthestreet

Grumps wrote: »

I've got a similar question but not involving Building Regs.

Daughter (and family) are in a house with a flat roofed kitchen extension. Having removed the 'faux' timbering, the ceiling is in such a mess that it will be easier to drop the lot and replace the plasterboard. I am anticipating that there will be NO insulation above the existing ceiling.

Therefore I will be looking for a 'rigid' product to cut and place between the ceiling timbers.

Any suggestions please? Product name? And will it fit in the car or need to be delivered? Obviously I am mindful to leave an air gap between the top of the insulation and the underside of the roof structure. Judging by the span, I expect the ceiling timbers to be a minimum of 6" x 2".

Thanks.

Try Spaceboard - 50mm thick, comes in 4ft lengths, available in all the major DIY stores.

robv_3

maninthestreet wrote: »

Try Spaceboard - 50mm thick, comes in 4ft lengths, available in all the major DIY stores.

IMHO its a DIY version of kingspan or celotex, eg smaller sheets and more expensive.