Vapour barrier and insulation for new workshop

[MuzzerParticipant @muzzer]

As you say, its been around and in use for ages. I used a quilt insulation on the loft conversion in our Cambridge house about a decade ago and it seemed to be pretty effective to me. Without having done any hot box testing myself (regardless how realistic they are), I have no objective means of evaluating it but the experience in cold winter and hot summer was quite convincing compared to previously. Having said that, I fitted it all myself, so made certain there were no gaps or cold bridges, which is possibly where some installations come to grief, knowing how builders like to cut corners and possibly don't understand the subtleties of installation.

Incidentally, the workshop / dining room extension we are currently finishing off has 1" of polystyrene and 3" of rockwool in the cavities (polystyrene next to the outer skin) and the roof has 4" of Eurothane GP (polyurethane foam) between the 6" joists (under a breathable waterproof felt) and an additional 1" of the same foam over the underside of the joists. The plasterboard will sit on the inside of that. We could have used a quilt instead of the foam but it's more expensive and is best saved for when you want to save a few inches of space eg in a loft conversion where head height etc is valuable. And yes, it's been signed off by the local planning officer here in Lancs.

Murray

[Raymond AndersonParticipant @raymondanderson34407]

Well Muzzer, you have it in a nutshell re the quilt insulation. If it does not perform as it is specified to then it can usually be traced back to the installation. although it would have been more apt if you had said SOME builders and not lumped us all in the same category….

Worked on a new build some months ago. It was a nursery for Aberdeen UNI and the style was "PASSIVHAUS "

All penetrations through the insulation in the cavity had to be sealed even a single cable. Inside kit was 200mm thick as opposed to the usual 140mm None of the normal double or triple glazed sealed units for windows, these were special types, same with the external doors and frames. Even the cills and door soles were a special rigid plastic, not the normal pre cast units. Never worked on a building like it before. At the completion it was the subject to a barrage of tests and had to pass them all.

It is reckoned to be so efficient that the whole nursery can be heated / cooled with only 7 % of what a normal build would need using traditional practices and materials. The whole build was valued at 1.3 mill which is about double of what a "normal build of the same size would be. Although look at the savings on energy costs.

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