Insulation between 1st and 2nd floor.

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We moved to a flat in old Victorian house in Kent. We are not from here so for use British winter is very VERY cold.

House is 3 floors (ground floor, 1st floor, 2nd floor) has 3 apartments, each apartment is 170sqm, house on top of the hill and 360 degrees views, no buildings around so wind hit the house from everywhere, good views and nice air circulation as we have windows everywhere.

We are renovating the flat completely(we are the top flat, 2nd floor) we are insulating the walls with 100mm Celotex, and also renovating the loft and change insulation up there.

Problem is the floor:

Downstairs neighbour (we talk with her about temp she has), she sets the whole flat to 15 degrees Celsius during winter. And she has no insulation in walls as is not renovated. Plus one thermometer controlling all 170sqm flat, so I guess is not all unanimous temperature and is probably colder in other rooms.

We like our heating to 21 degrees during winter, (new boiler and smart heating every room),so every room is on check.

We have carpet as previous owner re carpeted not while ago, like a year before moving, it’s very thick.

We got tired and want to insulated under our floor as everything seems warm except the floor, when walking barefoot it feels cold but the body feels warm except feet. We have to put rugs on top of the carpet and the kids are complaining the floor is cold.

Builder who’s helping with our renovation advice not to insulate the floor as it takes the heating from downstairs and that benefit us (but I guess he don’t get the point as he is not barefoot and wears boots inside the house). But we differ. What heating we gonna take if downstairs is 15 degrees or probably less and the height of the ceilings are 3.2 meter tall, I doubt by the time the heat goes up and goes to my floor I’m getting something tbh. Am I crazy or we really are getting heating from downstairs?

Am I right putting insulation in between floors?
The underfloor is wooden planks and wooden joists, and then is the ceiling of our neighbour.

The gap between floors is 22cm, we thinking to put insulation and fill it. I guess that should do? Should we just fill 22cm or get more insulation and compress it a little bit to be tight.

what about air gap, does it need it mineral wool or glass wool?

thinking on something cheap, could I just use loft roll that is cost effective, or I have to go for something more expensive like insulation slab which is more solid but expensive. I will have to avoid celotex as is super expensive for whole flat.

Would it be needed to cover heating pipes? I hear is good to insulate them to avoid heat loss, but if I gonna put insulation would not be enough already? . About electric wiring, if left there on top of insulation, could it be fine by itself?

thank you.
 
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Warm air rises, so it is possible for heat to come into your flat from below.

Cold air doesn't.

It is possible for cold draughts to get into the space below the floorboards, for example if there is an unlined bay window roof against it, or a disfunctional hollow bay wall, and mostly enters through the gap under the skirting round the edges of the room.

More likely you are feeling a cold draught from doorways and the fireplace.

You can carry a smoking non-stick around to identify the path and source of draughts.

The carpet provides sufficient insulation against heat loss by conduction, and there will be no heat loss by convection through the floor.

Invest in some socks and slippers.

Mineral wool is not flammable, which I consider to be an advantage. The brown type treated with ecose (marked on the wrapper) does not shed dust and fibres.
 
Thanks for the info, the fireplaces had been refurbished and sealed so no draught around them, neither the doorways and we don’t have skirtings and the wall go until the floorboards and is insulated as well anyway.

I mean, if you go to the center of the room and put your hand in the floor or your feet, you can feel the cold sucking you up, like when you are outside and feel the soil sucking all the warmth if you walk barefoot there for example.

but that got me thinking, maybe is just as simple as lift carpet and subfloor planks around the outside walls, insulate over there, as we insulated walls but we didn’t insulate the wall gap between the neighbour ceiling and our floor.

do you think if we do that can be the solution or still needs to put some rockwool.
 
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Actually this is really good advice, thinking about socks and how to mimic their effect. I think the solution is as I remember to seal between subfloor planks to stop the draught from coming up or wherever it comes from, and then to put a ticker underlay for the carpet to mimic the socks effect, and that should do, will be cheaper and will not need rockwool, a foil backed one should do.
 
I think the solution is as I remember to seal between subfloor planks to stop the draught from coming up or wherever it comes from...
Or an older, possibly faster, approach - lift the carpet, lay a skin of hardboard over the floors, tape the joints and relay the carpet (ideally with a heavy felt underlay). I did this on a previous house and it worked a treat to stop draughts and make the upstairs warmer
 
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Oh wow, yeah that’s the real solution, thanks, ticker felt it is then, much appreciated
 
Can’t see how your neighbour can set the entire flat to one temp unless it’s open plan? If she has a stat in the hall (for instance)with no heat source the rest of the flat could be in the high 20’s before the stat is satisfied .
 
Actually this is really good advice, thinking about socks and how to mimic their effect.

I don't want to put words into @JohnD 's mouth, but I don't think he was suggesting to mimic the effect of socks. Rather, I imagine he was referencing the age old tradition of putting them on your feet.

And I must say, the effort of socks - and slippers - on feet is a far simpler and cost effective solution than any of the others mentioned.
 
Your flat sounds like the equivalent to an extension that we did above a double garage. The garage is not insulated, but pretty draught proof and the boiler is running in there. Even with frost outside the temperature is usually no less than 8°C. The extension room above has plenty of rock wool in the floor and the thermostat in the room set to 18 to 20°C depending who is in there. The floor is usually o.k. to walk on bare feet.
But taking up the floor boards to insulate the complete floor in your 170 sqm flat sounds a bit of a nightmare.
 

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