Loft Insulation

[Heather2011]

Hi,

I'm planning to insulate the loft (floor joists). A few questions here and would appreciate any advise.

The distance between the floor joists is about 57.5cm. Searching in DIY stores, I can't find precut rolls with the exact width but spotted a special offer with B&Q - £3 for 3 rolls, which is brilliant price. Would it be a good idea to try to use them. I was thinking that I can make them fit by
cutting one roll in the middle and use one and a half to fill in between the joists. Can anyone advise whether this could work?

In additiona to this, the loft has already had some loose insulation (cellulose fibre pellet) poured on the floor joists. Should I remove them before laying new insulation or can I just leave them there and lay on top?

Sorry about the endless question, the final one! The loft has already been insulated in between the rafters. They are quite old. I was told that these are called 'warm roof' and was used back in 1980s. If I now insulate the loft at floor level, would this create any problem on the rafter insulation?

Thanks, Heather

 

[Burnerman]

Fitting your new insulation that way would be absolutely fine, just don't leave any gaps!
Leave the existing vermiculite where it is - its totally inert.
For insulation between the rafters, there must be an air gap between the insulation and the tiles / slates - this keeps things dry. Whether its worth leaving it is debatable!
You could qualify for an insulation grant, you know....just have a wee google.
John

 

[Heather2011]

Fitting your new insulation that way would be absolutely fine, just don't leave any gaps!
Leave the existing vermiculite where it is - its totally inert.
For insulation between the rafters, there must be an air gap between the insulation and the tiles / slates - this keeps things dry. Whether its worth leaving it is debatable!
You could qualify for an insulation grant, you know....just have a wee google.
John

Thanks very much John! I can now happily go grab those bargain rolls now!

In terms of hte air gap between rafter insulation and the tiles, how can I check this? I had a look earlier on in the loft and it looks to me that the existing rafter insulation is glued onto some sort of felt. Does that mean there aren't any gaps there? I can, however, see plenty gaps in the eaves. Hope they would help with the ventilation and therefore keep things dry?

 

[Burnerman]

If the house was mine, Heather, I'd be inclined to remove the odd piece of insulation from between the rafters, and see if there are any nasties in the form of mould, etc, in there. There is likely to be an underfelt between the tiles / slates and the rafters, so leave that alone if you can.
Elderly buildings didn't have this felt, and relied on a sort of lime mortar pointing to glue the slates together from the underside.
Your gaps in the eaves don't mean a great deal really - there is no guarantee that air is circulating up to the top of the roof, but it does show that the soffits are vented.
Worry ye not! If there were roof problems they would have shown up by now so go ahead with your insulation - but dont forget if there are any water tanks up there they will have to be cared for too as the immediate area will soon be much colder.
Don't forget a dust mask and the usual anti prickly clothing.....and try not to slip off the joists and push a knee through the ceiling
John