Cold suspended floors - will a good underlay help?

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Hi all,

We have a house with suspended timber ground floors and tons of airbricks. Whilst this gives the timbers good ventilation it leads to very cold floors, especially at this time of year. I'd love to insulate underneath them but that is a bit impractical for a few reasons:

1) I'd need to lift all of the floorboards as there's no access underneath. Not easy to plan around the family!

2) The joists are only 100mm deep and supported by several solid brick dwarf walls. This means I'd need to leave gaps in the insulation above these dwarf walls to allow cross ventilation, or just put a thinner layer (50mm?) in those areas.

So I'm wondering if just doing as much as I can from above will make a worthwhile difference. I know it won't be as effective as a proper insulating regime, but would it help to stop the floors feeling so cold? Cold feet and ankles, plus getting chilly when playing on the floor with my son.

We're planning on replacing all of the carpets soon so I'm thinking about the following:

1) Caulk any noticeable gaps between the floorboards and caulk between them and the skirting.

2) Lay down a thick flooring paper, taping the joints, to seal off any minor gaps / draughts.

3) Use a thick felt underlay with a high insulating value.

4) Carpet.

Is the above likely to make any noticeable difference? Or do you have any other ideas on doing a proper insulating job underneath, bearing in mind the dwarf wall issue?

Thanks,
Andy.
 
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Personally I think thats a good plan - you may like to consider foam matting that can be laid below laminate floors at the same time?
Particular attention to skirting gaps is valuable to minimise draughts and prevent black dust lines forming.
John :)
 
I am a flooring retailer (just for your info)

Older propertys were designed to be draughty to give the open fires ventilation. Modern fashions are for a more "airtight" setup.

quickest fix we use is simply to fix plywood (6mm) to the floor (nice and tight joins please) before fitting your desired flooring. This will make a huge difference! But if you still have an open fire get ready for the room filling with smoke :eek:

Modern PU foam underlays also help "insulation" and of course if after plyboarding you still have massive gaps under the skirting boards then fillets of wood or caulking will sort them out

Once your flooring is down you will soon have warm feet
 
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Thanks guys.

No open fires to worry about here :)

Would you suggest a pu rather than felt underlay then? I know the likes of cloud 9 have a high tog rating but some of the felt type seem higher.

I did consider putting down some 3mm self adhesive closed cell foam underlay first (B&Q solid wood flooring type) but thought it might get a bit messy. Ply (or maybe hardboard). sounds like a good option though.
 
A natural felt underlay with high tog rating would have a number of advantages over puFoam albeit feel a little firmer, I would definately favour natural felt.
 
Had some of the carpets up today to have a squint at what the floor boards were like. I have to say, there were some massive gaps around the edge of the floor, particularly under the bay window. It was blowing an icy gale through them!

In some places the floor boards were nearly ½" away from the skirting, much too big for caulk so I rifled around in the shed and found some closed cell sealing foam strip I had left from an old project. Think super heavy duty draught excluder. I wedged this into the big gaps, caulked up all of the smaller ones, and I've put strips of 2" masking tape over all of the floor board joints I could get to.

It may be my imagination but it already feels warmer in there. We still haven't ordered the new carpets but I'm looking forward to stripping the rooms out completely so I can do a thorough job off sealing up all of the edges and gaps. With that, and good quality felt underlay I think we'll have a much warmer ground floor with minimal outlay. Got to be a good thing for a Yorkshireman :LOL:
 
Had some of the carpets up today to have a squint at what the floor boards were like. I have to say, there were some massive gaps around the edge of the floor, particularly under the bay window. It was blowing an icy gale through them!

In some places the floor boards were nearly ½" away from the skirting, much too big for caulk so I rifled around in the shed and found some closed cell sealing foam strip I had left from an old project. Think super heavy duty draught excluder. I wedged this into the big gaps, caulked up all of the smaller ones, and I've put strips of 2" masking tape over all of the floor board joints I could get to.

It may be my imagination but it already feels warmer in there. We still haven't ordered the new carpets but I'm looking forward to stripping the rooms out completely so I can do a thorough job off sealing up all of the edges and gaps. With that, and good quality felt underlay I think we'll have a much warmer ground floor with minimal outlay. Got to be a good thing for a Yorkshireman :LOL:

Ahhhhh!

....didn`t notice your location!

....clearly you are going to be far too "tight" to ply the floor which would be quicker more effective, but......

cost money!!!!!!!!!!!!!!!!!!!!!

Good luck - your method will work but take bloody ages!
 
:LOL:

I haven't ruled out the ply, I was just trying to sort some of the really bad stuff for now. The gaps around the edge would still need caulking anyway, and I've got close on 40m² to cover so it's a not insignificant extra cost.

6mm ply is more expensive per square metre than some of the carpets we've been looking at :oops:
 
Wish someone had suggested the ply option to me.

I caulked all the skirting boards to the floorboards and gaffer taped all the floorboard joints in the room. Then fitted the best underlay I could find with good quality wool carpet.

The floor is still cold.
 
Lower - I'm not expecting miracles from the ply.

Whilst I'm not doubting lymmrangers advice, at the end of the day ply has (virtually) no insulating value, it'll just be there to kill the draughts, which is why I'm in two minds about using it.

I know that nothing I do above the floor will make a significant difference as far as insulation goes so I'm just trying to make the best of a bad job I guess.

I've even had a crazy thought about raising the floor level! I've got enough 25mm celotex board to do the main front room. Some chipboard flooring boards on top of that and at least it ought to make some kind of difference.

Might keep banging my head on the door frame or tripping over the step on the way in though :LOL:
 
its the draughts that are making your room feel cold......

I also live in a house with a suspended timber ground floor

I have air bricks every 3 feet on all external walls

6mm ply warmed us up more than 10 degrees (felt like it anyway)

I am in the "game" and it was what I was advised to do.....


you asked for help - we cannot force you!

(Oh and no one said ply had any insulative value))
 
Please don't get me wrong, I really do appreciate your advice and am not knocking it in the slightest (as I mentioned).

I know I joke about being tight but after working outside in this God forsaken weather all day I'm sick of returning to a house which is so cold downstairs but almost tropical upstairs, so I'm just scouting around for the best possible solution for my particular situation. I can feel a difference just from the rudimentary draughtproofing I did over the weekend so I know what you're saying is right, I'm simply trying to see if there is anything else I can do to improve upon it further :)
 

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