Attic insulation - plan to convert down the road. What would you recommend

Bad Chemicals

Hello, we are renovating a 1950s 3 bed semi and, after replacing the single glazed windows, the next greatest source of heat loss is the attic.

We were going to go with spray foam insulation until the recent furore about it (mostly in UK). Another problem with it is that to avail of SEAI the foam will need to protrude past the rafters, meaning when we want to put a ceiling in down the road we will be limiting head height.

Then we started looking at cellulose insulation on the floor of the attic. Again, to avail of SEAI it will need to be so thick that overfills the joists, so the only floor we could put in would be a raised floor, again limiting head height and reducing cost. We did get a quote for cellulose insulation and when I raised concerns about the floor and potentially just putting in less insulation, and forgoing the SEAI grant, I was ghosted!

Have other people had this issue, and what did you do? If we do go with cellulose on the floor alone, that means the attic room will be cold.

Maybe we could go with some cellulose on the floor (if we can find someone to do it) and kingspan insulated boards between the rafters on the roof?

Calahonda52

1: you either insulate the floor of the rafters, not both

2 good decision on the spray foam

3: the sketch from another project is just for ideas.

4: when the room is converted , then you need to have the thermal envelope along AC CB BD DD on both sides and CC will not need to be insulated

5: the conversion may require steel beams to be fitted so IMO you might consider getting the steel in before doing anything in the attic.

Pls post a picture of the roof trusses, they might mitigate against a conversion