Boarding my loft and insulation

Surbybird

Following on from my quesion about loft ladders, I also have to board my loft and it occurs to me that it might be a good time to top up my insulation. There is already a reasonable amount up there (it comes to within about 3cm of the top of the joists from what I can see while perching precariously on top of the step ladder!) but would it be more effective to remove what is there (hoping the answer is 'no') and replace it compeletely?

Presumably if I go with topping up I just put the insulation material on top of what is there and then fix the boards on top? Do I need to leave an air gap between the insulation and the boards?

I hate DIY.

:mad:

ormus

just top it up to the top of the joists. no need to replace it.
then board it out. no need to leave any gap.
ideally you need 270mm in total. (current regs).

you can also try this: or similar product.
http://www.space-insulation.com/board.html

Surbybird

ormus wrote: »

just top it up to the top of the joists. no need to replace it.
then board it out. no need to leave any gap.
ideally you need 270mm in total. (current regs).

you can also try this: or similar product.
http://www.space-insulation.com/board.html

Thank you! I am glad that I can just top it up as I didn't much fancy the thought of taking it all out first.

Kind regards

Kate

27col

Even if you top up to the top of the joists this is not going to provide a serious amount of insulation. Probably a maximum of 100mm. As ormus says, you really need to go up to 270mm.if you are serious about improving the insulation level in the loft. If you are insistent on boarding out the loft, it would make a lot of sense to board out the absolute minimum area that you can manage with. Then apply a much thicker layer of extra insulation everywhere else in the loft. This would have the effect of raising the average insulation level in the roof, whilst allowing some storage.

Surbybird

It's already full of insulation to within about 3cm from the top of the joists so if I put 100mm on top it would take it to 70mm above the joists. Is that not enough? I am assuming that there must already be about 200mm there so that would make 300mm. Once I put the boards on it will be packed pretty solid.

Or am I completely wrong? (it has been known...)

AdrianW2

Your joists are 23cm deep?

Don't pack insulation down. It's the air that does the insulating, no point having the insulation if you're going to squeeze the air out.

Canucklehead

Good morning: you need to take into consideration any wiring you might have in the loft space before you insulate...more here.

HTH

Canucklehead

Surbybird

AdrianW2 wrote: »

Your joists are 23cm deep?

Don't pack insulation down. It's the air that does the insulating, no point having the insulation if you're going to squeeze the air out.

Well, I am guessing, based on what I was told and what it said in the HIP pack when I bought the house! I can't currently get up in the loft but once my ladder is in place (see my other thread) I can get a better idea of how deep it is and how much more I need to put in before I put the boards down.

This insulation malarky is a lot more complicated than I thought it was going to be!

Surbybird

Canucklehead wrote: »

Good morning: you need to take into consideration any wiring you might have in the loft space before you insulate...more here.

HTH

Canucklehead

Thanks for the link - I shall have a look.

Well, at least I know where the wiring is because having just had the house rewired, the electrician very helpfully laid it out nicely and told me where it all was. However, I might just skip putting more insulation in and board it all over and live with what is there!

AdrianW2

Surbybird wrote: »

what it said in the HIP pack

Our HIP said, IIRC, 75mm. When I got up into the loft it was clear from the bare plasterboard that there wasn't any at all.

I wasn't going to wade into the electrical cabling issue but since I'm posting. Once of the reasons I got nPower's contractors in to do our loft was because I didn't fancy laying a vapour barrier and moving the cables. In the event they didn't bother either and just dumped the insulation on top.

27col

AdrianW2 wrote: »

Your joists are 23cm deep?

Don't pack insulation down. It's the air that does the insulating, no point having the insulation if you're going to squeeze the air out.

AdrianW2 you took the words right out of my mouth. Great minds think alike!