Insulating vs. new floorboards

[samaudio]

Hello,

We have exposed floorbards in the downstairs of our Victorian house. The cold and draught coming from below is a major problem in winter.
I decided to use celotex to insulate the boards from below, however upon getting under the boards to assess how difficult it would be, I have decided against it. There is barely any room under the floor in most areas and I don't want to take the entire floor up.

So I am now considering putting a new tongue and groove floor on top of the existing floor (as the boards are pretty beaten up anyway). This would cause much less disruption and I think I could do it fairly cheaply.

I was wondering if there is any type of (thin) insulation that you can put under a new t&g floor, I had intended to use 3mm ply to ensure a flat surface to put the new floor on, but would like some insulation from the cold below...

Any ideas?

 

[TheVictorian]

Draught is probably the biggest heat loss here so sort that and you have resolved a big chunk of the problem. You could pop some of those fibre boards that are used under laminate flooring under your ply, that would have a minor insulating effect.

I think I would put reclaimed floorboards on top to try to preserve some of the character, seems a shame to bury your original floorboards under ply and a new floor.

 

[geraldthehamster]

I agree it would be a shame to put a new floor on top. It would also create issues with hearths, skirtings and door threshholds. Have you considered discreet application of frame silicone into the worst gaps, and the application of Persian rugs?

cheers
Richard

 

[geraldthehamster]

This thread ought to be moved to Floors, Stairs and Lofts...

 

[samaudio]

I agree in principle that it would be a shame to cover an original floor, but actually the floor is in very poor condition and is painted, as a large area had to be replaced with new pine boards. It is quite abused and dented/cracked/filled etc.
I did buy draughtex rubber strip and fitted between the boards, but it didn't seem to do much to combat the problem.
My thought is to cut an amount from the bottom of the skirting all round, to fit the new boards in neatly (the skirting is quite high). And we would do the entire ground floor, so thresholds shouldn't be too much of a problem...
We already have a couple of beautiful persian rugs - they are good for draughts, but don't cover the whole floor, sadly!

 

[geraldthehamster]

In that case, to be honest (and speaking as an inveterate floor puller upper) I'd be tempted to pull up the floor, insulate underneath with Celotex, and put some reclaimed boards down - or you can get new boards that are re-sawn from old timber beams, which have the advantage of no damage (I have some nice pitch pine ones in my bedroom). You should be able to get the boards out/in without removing the skirting (though this isn't guaranteed!), or having to shave the bottom of the doors. Obviously I'd do this one room at a time. It would be quite disruptive, but you'll need to empty each room to lay a new floor in any case.

Cheers
Richard

 

[samaudio]

Hmmm, I don't relish the idea of pulling up the entire floor! Although it would be good to get insulation in underneath.
Also, I haven't had good experience with reclaimed - when I had to replace an area of floorboards, I wanted to get reclaimed to fit in visually with the rest of the floor. After trawling through several yards, I only found badly damaged boards that were barely useable.
Where did you source the re-sawn ones? And what was the rough cost? (I'm guessing not as cheap as new pine boards).
Thanks,
Sam

 

[geraldthehamster]

Mine were from here:

http://www.reclaimedfloorboardsuk.co.uk/


Cheers
Richard

 

[JohnD]

rip it up. Once you get started it will not be hard.

It will not only save your skirting problem, but also the doors which will not fit a higher floor.

Once it is up you can clean out your subfloor void, unblock the airbricks, lag pipes, pack mineral wool between the joists to block draughts and to insulate, treat woodworm, lay cables incl. internet, TV, phone, alarm and speakers, and lay your nice new floor on top.

 

[geraldthehamster]

A good method, once you get the the first board or two up, is to put a bit of 4x2 across two joists, and use another bit as a lever. A vigorous action can remove several boards at once, in short order. Just make sure not to displace the joists

Cheers
Richard

 

[TheVictorian]

As above, once you get going it is an easy and not that dirty job to pull the floor up.

 

[endecotp]

I agree that you should probably lift the floorboards. I've investigated options for a similar project, and the best insulation you could lay on top of the existing floorboards is this:

http://www.proctorgroup.com/images/...therm/Proctors - Spacetherm C - Datasheet.pdf

But it's very expensive. It might make sense if you were going to carpet over it, but if you want to lay more wooden boards then it's getting rather thick with obvious implications for skirtings etc.

 

[AronSearle]

Do a half hearted job and expect to get half hearted results.

Draught proofing without upgrading the insulation will likely result in more internal condensation and mould issues, particularly around and above the skirting area, unless you increase ventilation elsewhere (which obviously negates your draught proofing) or run dehumidifiers.

 

[geraldthehamster]

I can sort of see where you're coming from, but I don't think condensation and mould is very likely - maybe on an external wall. Victorian houses are usually quite well ventilated (unless they have plastic abominations instead of windows) - but you don't tend to get low level condensation in modern houses either.

I'd certainly insulate. All my floors are insulated and it makes a noticeable difference. A search of this forum for "suspended floor insulation" will bring up plenty of discussion on how to do it. My preferred method is Celotex between and/or under the joists, completely sealed with expanding foam, making sure that all the air bricks still ventilate the space undeneath.

Cheers
Richard

 

[BenTheDog]

I agree with everything Richard and others say above. It will be hugely less trouble to lift and relay with properly sawn reclaimed boards. I made the mistake in our bedroom of taking up all the old boards, half of which were damaged, then buying 'new' second hand boards from a reclaim yard. The problem was, getting boards that were all the same width and thickness. I half managed it, but it was a pain to do, there are gaps and slight differences of level in spite of sanding, and I am not really happy with the results.