Building control necessary to replace system-built wall insulation?

ed110220

I plan to replace the old fibreglass insulation in the exterior wall of one of my rooms with more efficient polyisocyanurate (PIR) board insulation when refurbishing it.

The wall is a little unusual as it is system-built rather than the usual cavity or solid wall. The present construction is, from inside to out, hardboard on timber studwork/noggins between steel uprights, glassfibre insulation, cavity then steel cladding.

Building control speaks of permission being necessary to install cavity wall insulation but what about replacing insulation? Does this even count as a cavity wall? Is building control a palaver and is it expensive?

Using a u-value calculator, replacing the insulation will bring the value from a present 0.55 W/m2K down to 0.18, so it will be well worthwhile (I believe the value for a new house's walls has to be no more than 0.27)

Canucklehead

Hi: see here.

HTH

Canucklehead

ed110220

Canucklehead wrote: »

Hi: see here.

HTH

Canucklehead

Thanks Canucklehead, but that only speaks of masonry walls when it talks of cavity or solid types - my walls have no masonry. They are steel cladding/timber/board on a steel frame.