Insulating attic light shaft - fibreglass v Kingspan type panel

AC_Dublin12

Hi there,

I'm currently getting quotes from contractors to insulate my attic. Thequotes for insulating the ceiling with fibreglass/earthwool or theirequivalents are quite similar however there seems to be a difference of opinionwhen it comes to insulating the light shaft for our bathroom velux window whichextends through our attic.

Some contractors are saying just to wrap earthwool around the shaft and wrapit in netting, this leads to a competitive quote.

Others are saying that this is not best practice and we need to create asealed box structure around the light shaft with a Kingspan like panel in orderto seal off the shaft. Their reasoning is that the bathroom will generate a lotof heat transfer with steam and the earthwool is not the best product for dealingwith these conditions. These quotes naturally come in a lot dearer as thematerial and work involved is more expensive.

Any opinions on this?

muffler

Hi AC_Dublin12, welcome to the forum. We would appreciate if you would use the default font size 2 in your posts. I have changed the sizing of the text accordingly.

Thanks

Borzoi

Others are saying that this is not best practice and we need to create a sealed box structure around the light shaft with a Kingspan like panel in order to seal off the shaft. Their reasoning is that the bathroom will generate a lot of heat transfer with steam and the earthwool is not the best product for dealing with these conditions. These quotes naturally come in a lot dearer as the material and work involved is more expensive.

This is the far better option - you can get a better install. And unlike the fiberglass, the structure won't collapse under it's own weight. It is unfortunately a more expensive option.
I'm doing the same in my own house at the moment, to get 100mm around the light well is costing about half the cost of the rest of the job in terms of materials

Maudi

AC_Dublin12 wrote: »

Hi there,

I'm currently getting quotes from contractors to insulate my attic. Thequotes for insulating the ceiling with fibreglass/earthwool or theirequivalents are quite similar however there seems to be a difference of opinionwhen it comes to insulating the light shaft for our bathroom velux window whichextends through our attic.

Some contractors are saying just to wrap earthwool around the shaft and wrapit in netting, this leads to a competitive quote.

Others are saying that this is not best practice and we need to create asealed box structure around the light shaft with a Kingspan like panel in orderto seal off the shaft. Their reasoning is that the bathroom will generate a lotof heat transfer with steam and the earthwool is not the best product for dealingwith these conditions. These quotes naturally come in a lot dearer as thematerial and work involved is more expensive.

Any opinions on this?

i have one of these ridiculous light shafts too...mine is wrapped in rock wool in the attic then slabbed.this is all you need to do..dont go mad expensive with it cos one day you may convert your attic and remove said 'shaft' altogether.

scrgirl

Maudi wrote: »

i have one of these ridiculous light shafts too...mine is wrapped in rock wool in the attic then slabbed.this is all you need to do..dont go mad expensive with it cos one day you may convert your attic and remove said 'shaft' altogether.

How much does this job cost roughly?