Laying wood floor in first floor flat

[johnmcmullin]

Hello everyone,

I have just purchased a 1st floor flat in a 1910 conversion, to live in myself. Currently there is a badly installed laminate floor throughout. This was laid on top of an old carpet, on top of chipboard panels, over the original floorboards. I really want a real wood floor but realise that going back to the original floorboards might cause sound insulation problems. I can't really stand carpets.

There seems to be a sag in the middle of one or two of the rooms as well.

I am thinking that I will pull up the carpet, put an underlay on top of the chipboard, and then lay down pine tongue and groove boards which I will stain and varnish myself.

Can this be a floating arrangement and will it be sufficiently quiet for the downstairs neighbours? What is the best underlay to use?

Also, is the sag in the floor a problem? There was a small leak in a radiator that rotted one of the chipboard panels in the saggy part of the floor. This caused the laminate to snap in that area.

Thanks very much for your opinions. I wish I could just sand the original boards really but I realise that'd be anti-social.

Regards,

John

 

[ajrobb]

Currently there is a badly installed laminate floor throughout. This was laid on top of an old carpet, on top of chipboard panels, over the original floorboards. I really want a real wood floor but realise that going back to the original floorboards might cause sound insulation problems. I can't really stand carpets.

I suspect your lease says you must have carpet, most conversion leases seem to. This is usually because you might only have 6" joists. One specification for floors in modern flats is 10" engineered joists with an ordinary floor above and ceiling below. Given the stiffness goes up with the cube of the height, makes them over 4 times stiffer. Another specification is to have a floating floor above, a resilient ceiling below and sound absorbing mineral wool in between.

OK, so you want to go for the floating floor bit. There are various products that you can use. A quick Google shows
http://www.soundservice.co.uk/part_e_timber_suspended_floor_R-10.html

The chipboard (preferably 18mm exterior grade T&G ply) floats on top of this resilient layer. The joints in the floating layer are glued.

In fact, the best material to float on top of the resilient layer might be 18mm T&G cement bonded particle board. This is heavier than chipboard or plywood. (It is also waterproof, fireproof and vermin proof.)

A hard floor surface will generate more impact noise than carpet unless you creep around in socks. Scraping of chair legs is also particularly awful.

Also, is the sag in the floor a problem? There was a small leak in a radiator that rotted one of the chipboard panels in the saggy part of the floor. This caused the laminate to snap in that area.

I think you are going to have to take up the flooring, chipboard and carpet and inspect the original floorboards and joists. I had a leaking bath seal that destroyed the twin joists below:

Untitled

• ajrobb
• 24 Apr 2010
• 5

Hopefully, it will just be the chipboard that's gone soggy.

 

[johnmcmullin]

Thanks for your reply.

Sorry for seeking clarification. I think that the resilient bar under the joists option isn't possible because that would involve taking the ceiling down in the flat below.

Do I need to lift the joists and put in mineral wool between the joists? Before replacing the floorboards and putting in soundproof matting.

Also, at the end of it all, I want a real wood layer on top. Would I just float the pine tongue and groove over the quietboard or is another layer needed on top of the chipboard in order to keep down the sound?

Is the sag in the room a problem for the panels which are all very rigid?

Many thanks,

John

 

[ajrobb]

Do I need to lift the [floorboards] and put in mineral wool between the joists?

I'd discuss this with the freeholder and/or flat below

Would I just float the pine tongue and groove over the quietboard or is another layer needed on top of the chipboard in order to keep down the sound?

If you float and glue together T&G chipboard on top of the resilient layer, I think you can nail/screw your pine floorboards to that.

Is the sag in the room a problem for the panels which are all very rigid?

As you say there may be some water damage, you'd need to inspect the existing floorboards and joists. If the floor is in good condition but warped, I suppose you could lift the floorboards and fit tapered firring strips to the joists to flatten the floor.