Converting attic - what insulation to use?

[Paul Moore]

Hello,

My next home project is to convert the attic. I was wondering about insulation. Should I use loose stranded fibreglass insulation like Rockwoll, or a solid insulation? I was planning to clad the ceiling with wood panelling, and I thought that glass fibres might escape through the cracks between the panels and contaminate the air.

Should I also use a plastic sheet between the insulation and the wood panelling? I suppose that this should also seal the glass fibres in place?

Many thanks, Paul

[Christian McArdle]

Conversion of a loft comes under building control. There are many, many issues that must be addressed to make it legal. You'll need to consider the following (and loads more I've forgotten).

1. Insulation (for maximum thinness, this is best done with Kingspan/Celotex. There are loads of rules about air gaps, cold bridging, thickness, breathable membranes, vapour barriers etc.)
2. Fire escape (usually you need to make your stairway fire proof (no open plan lounges) and install an escape window in the loft. There are many other methods of complying.
3. Fire alarms. You'll need mains powerered linked smoke detectors.
4. Fire protection. You'll need fire resistance between the top floor and the others.
5. Foundations. They will have to be strong enough for the extra weight.
6. Walls. They will have to be strong enough for the extra weight.
7. Floor joists. They will almost certainly need replacing or supplementing with much stronger examples.

Christian.

[Rob Morley]

Are they pretty much the same in Belgium as in the UK?

[Paul Moore]

Rob and Christian,

From what I've seen here, what regulations there are are usually ignored!

[Owain]

The Regs aren't even the same in England and Scotland.

Owain

[John Rumm]

Nope (except for under the floor where it will let you meet the fire and noise transmission regs)

or a solid insulation? I was planning to clad the ceiling with wood

Use PIR foam, it is one of the few ways to meet the required u Values and not lose too much headroom.

Should I also use a plastic sheet between the insulation and the wood

No need - it is foil covered. You can tape the joins with foil tape to keep them air tight.

[John Rumm]

Looking at the UK regs, they are to be honest mostly just common sense. They are also pretty easy to comply with.

You may choose to ignore them but since they are primerily concerned with ensuring you are able to escape from a fire, and you have a room that is quiet, and maintains a comfortable temperature all year round, the only people you ultimately end up cheating if you avoid complying with them is you and the family.

[leon]

Hi, we are just having a loft conversion done and the insulation we use was tri-iso super 9 its 14 layers but only about 20mm thic uncompressed its good stuff. Its not cheap but depends on what your using it fo

-- leon

[Matt]

If as expected we have a very cold winter do come back next summer and tell us all exactly how it performs.

[polomora]

Lads,

Belated thanks for the ideas here.

Cheers, Paul