Attic Insulation advice

chris_ie · 18-01-2022 4:52pm #1

I've been looking at getting my attic insulation upgrade/replaced. Had a few insulation guys out but wasn't too impressed. To be honest, they didn't give much of an assessment or advice. One crowed had suggested spray foam before even really seeing the attic space. On looking at their info, they seem to be doing spray foam the majority of the time. I don't want to go down that route. Another fella basically said he'd do half the job.

So, I'm tempted to just DIY it.

Basically I have a 2 storey house with converted attic. There is attic crawl space to the front and back of the house, with a small attic space above the attic rooms. There is a single layer of fiberglass insulation between the joists at the minute. Compressed in places, twisted in others. Random foam board insulation panels under some of the fiberglass (panels that fell off from behind the knee walls because they couldn't be bother to fit it due to plug sockets, radiator etc..) And, as mentioned, parts of the knee wall not insualted with others poorly fitted.

Another big thing is that under the attic floor isn't insulated (understandable), but the gaps between the joists under the attic room floor are not sealed. i.e I can see right under the attic room floor from the crawl space. So, warm air can leak into the attic space and cold air can get down. You can feel this downstairs at times. None of the insulation guys said anything about this when I pointed it out. I've seen guidelines online where they seal these gaps to prevent heat loss. Anyone on here done similar?

So my plan is to seal those gaps, if theres no issue. Remove the insulation that is down. Replace this with Rockwool or similar and insulate the water tanks (currently not insulated). I had planned on doing two layers of insulation, but I'm wondering if one layer would be good enough? The joists are about 225mm deep. If not I'd roll another layer across the joists. I was hesitant to do this myself due to making sure air gaps are maintained etc but might not be too difficult.

The other issue is above the attic rooms. The room with the hatch is insulated above using fiberglass rolls, but the other room has nothing at all! Its a bit of a tight crawl to get over to those rooms as there is no hatch in those rooms, and you have to reverse crawl to get out 😄 So I'm trying to figure the best approach here. Options being, use rolls also, precut and then drag them up into the attic space, use blown in insulation somehow or add a new hatch in the other room to make access easier and do rolls from that side.

Apologies for the long post!