Insulation material on top of floorboards

[DIY-A]

Hi all

Newly joined here, Looking for some help in regards to insulating suspended wooden floor in my lounge.

I was going to lift up the boards and install membrane and insulation method between the joists but the floorboards a pretty delicate now and tend to break easily after trying to lift a couple, also budget doesnt really allow to replace the whole floor etc. So ive decided against this solution

Another solution I found was some foil insulation which state that the product can be laid over the top of the floorboards and then sealed around the perimeter of the room with foil tape and then lay the finished floor over the top of this. Hence creating an airtight space. This will help with the draught's coming in from the gaps around the perimeter and also warm the space up

Now im worried about condensation appearing on the face of the insulation which will be against the floorboards. I checked the specs on some of these insulation foils and they say condensation doesn't occur because they are built up of multi layers but around 4-6mm in thickness but im still worried that over time there might be condensation occuring. I think the stack up is foil on the outer sides with a foam middle layer. Does this sound like it would work?

The other method would be to tape up the perimeter of the room with foil tape to close the gap between ends of the floorboards and the walls, But the areas of the floor close to the external wall where the air bricks are will still be cold

Has anyone had any experience with insulation floorboards from the top like this? I was thinking that I could coat the floorboards with a wood treatment to make them water proof and then have this kind of insulation on top. Would this work?

Hope you can help, Thanks

 

[Lower]

I replaced the suspended floor in our lounge because it was rotton and had some woodworm and insulated the replacement floor with 100mm pir foam between the joints. We also fitted a hgih tog underlay and the carpet. Disappointedly, we've not noticed any benefit from the new insulation. The floor is still cold.

 

[DIY-A]

I replaced the suspended floor in our lounge because it was rotton and had some woodworm and insulated the replacement floor with 100mm pir foam between the joints. We also fitted a hgih tog underlay and the carpet. Disappointedly, we've not noticed any benefit from the new insulation. The floor is still cold.

Yea I didn't want to go down this route only to find it did not improve anything. The floor could ideally be replaced as it is abit tired now but costs won't allow so I repaired what I can. An insulation over the top of the floorboards would be good but just need a definite answer on the condensation issue if there will be or not using a foil insulation which is sealed up around the perimeter. Becomes an airtight seal from the void below but there's no gap between the insulation and the top of the floorboards so need to know what issues could arise

 

[John D v2.0]

Anything thin that can be laid over the floorboards will help with draughts but not insulation. However given how draughty most suspended floors are, this can be a massive improvement for your house!

Regarding the benefit from 100mm PIR this will be very big, but again the draughts must be addressed, as these will negate the insulation.
Make sure the boards are hard against the bottom of the floorboards, and cut accurately. Then either foil tape the edges to the joists and foam to the wall, or you could try to put a poly sheet in there.

Even with insulation, a floor is never going to feel "warm" as the room will be heated to 20c and your body is 37c. But the floor temperature might be 18-19c instead of 12-13c when it's freezing outside. If you want a warm feel, UFH is the solution. Or thick socks!

 

[JohnD]

Another solution I found was some foil insulation which state that the product can be laid over the top of the floorboards and then sealed around the perimeter of the room with foil tape and then lay the finished floor over the top of this.

If you put anything on top of the floorboards you will have to saw the bottom off the doors. This is the worst idea.

You talk about floorboards breaking up. Are they planks, or chipboard?

How old is the house?

 

[DIY-A]

If you put anything on top of the floorboards you will have to saw the bottom off the doors. This is the worst idea.

You talk about floorboards breaking up. Are they planks, or chipboard?

How old is the house?

The multifoils I saw are around 4-6mm so shouldn't be too thick. I'd have to trim the doors anyways for the laminate flooring so not much of an issue there
They are tongue and groove from the 1950's. Started to take up a few and they started to crack pretty easily