Insulation under 1st floor floor boards

paddypaws101

As above! Next week I am getting my bedroom floorboards sanded and sealed. We are planning on lifting and shifting to close gaps so it seems like a good opportunity to add some insulation. 

Suggestions? Options I am
considering are A) the stuff usually used under laminate which comes in rolls. I think this could offer sound deadening as well as heat insulation. 

rock wool
if this option, can we just stuff the cavities between each joist or should we suspend it in netting? 

As it’s first floor I don’t want cost or bother of the more solid sheets which need cutting to size between joists 

grumbler

paddypaws101 said:

As above! Next week I am getting my bedroom floorboards sanded and sealed. We are planning on lifting and shifting to close gaps so it seems like a good opportunity to add some insulation. 

Usually it's next to impossible to lift the boards without breaking or damaging them because of rusty nails.

considering are A) the stuff usually used under laminate which comes in rolls. I think this could offer sound deadening as well as heat insulation. 

Waste of money and effort IMO. Too thin.

rock wool
if this option, can we just stuff the cavities between each joist or should we suspend it in netting? 

No need to suspend as it's not heavy, but

• do you really need thermal insulation on the 1st floor?
• for soundproofing there are special mineral wool mats (very easy to cut if needed).

FreeBear

paddypaws101 said: rock wool

if this option, can we just stuff the cavities between each joist or should we suspend it in netting?

As I have been removing ceilings on the ground floor here, I've been shoving rockwool/fibreglass insulation between the joists (no netting). It has reduced some types of noise being transmitted through the ceiling - Heavy footsteps are still a problem, but a decent underlay upstairs should help with that. The insulation has also cut down on draughts, which has helped to keep the place warmer.

Not sure I'd want to try fitting insulation by lifting the floorboards, but if you are having them up anyway, the cost of insulation is pretty minimal.

king132

paddypaws101 said:

As above! Next week I am getting my bedroom floorboards sanded and sealed. We are planning on lifting and shifting to close gaps so it seems like a good opportunity to add some insulation. 

Suggestions? Options I am
considering are A) the stuff usually used under laminate which comes in rolls. I think this could offer sound deadening as well as heat insulation. 

rock wool
if this option, can we just stuff the cavities between each joist or should we suspend it in netting? 

As it’s first floor I don’t want cost or bother of the more solid sheets which need cutting to size between joists 

I added 100mm rockwool inbetween the joist's when i rennovated my house. Its not expensive. My joists were not equal size so i cut the rockwool to the width and then push it through. Theres no need to add netting if you already have plasterboard ceiling underneath.
If you've got radiator pipes or hot water pipes going through, then it would be beneficial to lag them first (Climaflex) then add the rockwool.

the_lunatic_is_in_my_head

I'd use something like this over basic rockwall:

www.insulationsuperstore.co.uk/product/knauf-omnifit-slab-multi-application-100mm-x-600mm-432m2-pack.html