Thermal insulation requirements - over the top?

[RogerS]

Having just come off the phone to Kingspan I can't help feel that we've lost the plot (again). The rooms upstairs have part sloping ceilings and so the proposal is to insert Kingspan between the joists leaving an air gap between the insulation and the roofing felt.

But strictly speaking this airgap needs to be the size of the Mersey tunnel (50mm) to ensure that rats and mice can have unfettered access to my roof void. Nice hard strong elm rafters mean that they could be made smaller than softwood...which means that there's not enough depth between them to allow room for the Mersey tunnel and the insulation.....so he says put 100mm of insulation on top of the rafters and held in place by 25 x 50mm battens followed by plasterboard.....that's 6 inches!!!

Now the original building had (a) no airgap and (b) no insulation so I could stick up an egg-carton instead and that would be about 100,000 million% better then what was there before. So in the final analysis it's going to be left as it is unless I get a sympathetic building control officer.

 

[Scrit]

Now the original building had (a) no airgap and (b) no insulation so I could stick up an egg-carton instead and that would be about 100,000 million% better then what was there before.

Aren't the Building Regs wonderful! :roll:

Scrit

 

[OLD]

There is insulation available that meets the regulations thats quite thin look at page 566 in screwfix i am sure kingspan can give you info on there own high performance product.

 

[jasonB]

The Actis Tri-isosuper 10is only about 25mm thick, counterbatten then plasterboard so about 40mm height loss. And you could always chuck some celotex/kingspan between the rafters for good measure.

I used the tri-iso9 on this job, just staplegun to underside of rafers and batten out, I counter battened as I was fixing T&G.

Some BCO's don't like it though :wink:

Jason

 

[RogerS]

Old..are you referring to the Pitch Roofing insulation part 28148 for example?

Have to admit that I'm confused now as Screwfix claim to meet BR but list two u-values of 0.2 and 0.3. According to the Kingspan man, one needs to meet 0.2.

 

[RogerS]

Thanks Jason....I like that suggestion!

Also liked your gravity defying copper water pipes :wink:

Cheers

Roger

 

[OLD]

No its cat no86 part no 25009-86 a quilt material 0.2 u value. but i was using it as an example there are a number of manufacturers ,this high performance insulation looks ideal for your situation.

 

[RogerS]

Thanks, Old. Would you mind checking the part number as I can't find it on their website. Thanks

Roger

 

[jasonB]

Cat 86 is out of date, current one is 87 and I can't see any multi layer insulation in it, usually if you can't find the part No its been discontinued.

This is the Actis uk page

http://www.insulation-actis.com/

Jason

 

[OLD]

Yes its correct the roll is 1.5x10m at £225

 

[OLD]

Looks like i have binned the wrong cat. but like i mentioned it was just a example i am sure you will find a supplier.