Insulation on top of loft boards

[SlugDisliker]

Hello, I have a quick question about loft insulation. I have seen some differing views on the subject and was hoping to get your thoughts.

I am looking to insulate a loft which, I am told, currently has no insulation at all, and which is 90% boarded (apart from the eaves).

I do not know how deep the joists are, but the house was built in the 30s.

Due to time, distance and access constraints (rented property) I have to travel to the property and carry out the work in one day.

Having had a bit of DIY experience working in lofts, I know that the work can be quite awkward and the time can easily slip away, but I would like to get some insulation in now before the weather turns colder.

In an ideal world I would be able to go, lift boards, install insulation between the joists (75mm or 100mm), replace boards and put on a top layer (200mm).

However, I think it is likely that I will only have time to either:

1) Only lay insulation on top of the boards (probably 200mm top up)
2) Lift some boards, insulate between the joists (75mm or 100mm), replace boards and then lay insulation on top of all the boards (again 200mm top up)

If I can do 1) or 2) I can then return when I have more time to properly get the insulation between the boards.

Having read elsewhere it seems that condensation and building regs are the main issue with not putting the insulation between the joists.

Would just like to get your opinions on whether 1) or 2) is workable for this winter, with a view to doing it properly next spring?

 

[JohnD]

I think at the very least you need to pack mineral wool between the joists all round the edges, to prevent cold winds blowing through the gap between the loft floor and the ceiling beneath.

Are you a BTL landlord?

 

[SlugDisliker]

Thanks for that. Yes, I will definitely put wool between the joists where they are exposed. I am hoping that I can at least slide some wool underneath the boards, even if not all the way, as the boards should really be 90 degrees to the joists, but until I get there I won't be able to do much planning.

Yes a BTL landlord.