Insulating Between Floors

[tsomo2000]

Hi All

I live in a 1970's built semi, and its a really cold house. To try and help the heat situation I was thinking of insulating between the ground and first floor with rock wool (loft style) insulation.

Is this something that I will be able to do quite easily, by lifting the floor boards. From having a quick gander at google, it would seem that i need to ensure there is a gap left under the insulation, but if so, how much of a gap?

Is there anything I should not insulate (I will keep away from any electrical wires, but am I ok to insulate on top of radiator pipes?

Thanks

Alex

 

[mointainwalker]

How do you currently heat ? Are there operating heaters upstairs and downstairs ?

I ask because most people accept that heat leakage downstairs to upstairs is a reasonable way to heat bedrooms ( to a certain extent).

You might find it difficult to get floorboards up without mangling them and don't know if in 70's they were already using chipboard panels which will also be a pain. Do you have any tools ?.

If you get that far, it's easy to put in the insulation and you can lay it on pipes and you don't need any gap inside the envelope of the house. You have misunderstood that bit.

 

[tsomo2000]

I have fully working central heating with radiators in each room, the heating of the room is not really the issue, its more the heat retention, the rooms below the floor are very cold.

I have had a radiator replaced in the room, and the plumber had to take up a few boards, he seemed to make light work of it, so im hoping for the same.

For starters, I am just going to insulate the small bedroom floor, to see if it makes any/much difference.

My main concern was to leave a gap for the air to circulate (if required) as i didnt want to cause myself any future problems with condensation/rot if I put the insulation down wrong.

Ive just lifted a floor board next to the external wall, and cant believe how much of a draught I can feel. Im hoping that the insulation will make a bit of difference.


Thanks

Alex

 

[mointainwalker]

What is the downstairs floor - boards or concrete - and what covering do you have - carpet, parquet, vinyl ?

If downstairs is cold, it is far more likely that the floor is uninsulated and cold air in the underfloor void ( if not a concrete slab) is refrigerating your living room. Check for draughts, air-leaks around skirting-board and also around electrical sockets.

Are the walls insulated or do they also feel really cold ? I think a 70's house might, as standard,, have as little as 50 mm of insulation in the loft and that would be it .

 

[Deluks]

Yep, loft first, ground floor second. Insulation between your GF joists will make loads of difference.

 

[HERTS P&D]

If you live in a 70's house, the best thing to do is drop all the downstairs ceilings. Supply and apply loft insulation to the joists (leaving a gap around electrical wires) Then re-board with double skin plaster board and replaster.

Job done.

Andy

 

[mointainwalker]

@Hertdrainage

Why are you saying use two layers of pb ?

This is both a waste of cash and a waste of insulation space wtih an inferior material.

Please explain your reasoning .

 

[ajrobb]

I've just lifted a floor board next to the external wall, and cant believe how much of a draught I can feel. I'm hoping that the insulation will make a bit of difference.

I've just refurbished my 1978 build house. The joists had massive gaps around them as they go into the outside wall, which are a major source of draughts and heat loss. I packed the gaps with mortar, roughly in line with modern building practice. I think you are supposed to leave a rebate and finish with a bead of mastic to allow for shrinkage in new builds. I reckoned that the joists had shrunk enough over 30 years, so didn't bother.

And yes, I dropped the old ceiling (the nails were popping anyway). I considered resilient bars for the new ceiling but I have the stairwell in the lounge so it wasn't going to be easy or effective. Resilient bars, two layers of plasterboard and 100mm of acoustic (heavy) mineral wool are part of a standard noise reduction system.

 

[tsomo2000]

Yep, its a concrete floor downstairs (currently laminate floorring, but soon to be carpet).

So, if I was to install some insulation between the ground and first floors, would I need to leave a gap to let air circulate? I was thinking of using some netting, draping the netting across the joists, allowing it to drop around 100mm into the void, then stapling it in place, insulation would then go on top, and I would then just put the floor boards back as normal.

Therefore there would be a gap below the netting/insulation allowing for the air to circulate.

Thanks

Alex