I’ve been adding more roof insulation. We recently threw away a pile of junk in the lofty space. This has lowered the temperature in our bedroom in particular. I know this from years of monitoring the temperature with a thermometer most recently on a alarm clock. It hasn’t been as warm. I’ve also tried to put some in the roof space in the kitchen which has helped although I’m too claustrophobic to get in far enough to do everything that needs doing. Although I have not given up.
I’ve put a lot of loft insulation in the past in multiple goes, although not for a number of years. Part of the problem in doing it this way is I’m not sure how much is present. The UK building regulations suggest 270mm and any added on top of that is going to be less and less effective (and cost effective). Nevertheless laying stuff down and rearranging the loft space has led to me seeing places which need more.
I have used rockwool (glass fibre) in the past but its thoroughly unpleasant stuff to work with. Its very itchy on bare skin and gets in your lungs. One of my MSc lecturers in Biomedical science was a world renowned lung expert and reckoned it did no long term damage.
The more recent alternative is made from recycled plastic. This not only reduces the plastic waste problem (search this blog for other posts on that) but is very very nice to work with. No need to wear gloves and its easy to tear with the hands. The R-Value is almost identical to that of rockwool. For an explanation of R-values and U values see here.
What I have done over the last years with the floored bit of the loft is rescued “cloud nine” floor underlay from skips and laid it as a base layer of insulation (up to 5 layers). This should be reasonably effective and allows moving around. I’ve also rescued polyisocyanurate boards from skips and put as much as possible of our stored stuff on top of them. I’ve just discovered these my leach CFC’s becoming less effective over time. Now I’m filling in with 100mm recycled plastic shown above and I’m considering a rack shelving system so I can lay insulation under stuff.