engineered wood flooring - new subfloor and old subfloor

[46philh]

Engineered wood flooring in new kitchen / dinner.

We are having a kitchen / dinner extension. Existing area is 3 X 3m dining area and 3 x 3 kitchen. There are being knocked through with steel beams to support above. The new area will be 6.5m by 6m in total.

The existing house has a 5 foot void beneath it. Going to put kingspan between joists.

New extension has three foot void below timber joists.

In the existing dining area we have good solid floor boards from when it was built in 1960. In the kitchen we have flooring grade pine TG which has small bows in. The void area under here seem a little damp. Adding more air bricks.

Q. What are the options for the wood subfloor in the extension ranging from cheap to expensive long lasting?

Q. Do we need / should we to remove the kitchen pine TG floor boards ?


P.S We won't be moving house again so need the sub floor to last another 40 years!

 

[pinenot]

I'm going to presume you have access under the said floor to fit the insulation upwards, thereby keeping the existing floorboards intact!
If right, a vapour permeable layer fitted to the underside of the existing joists (fixed with rustproof staples) would provide two functions.
1. prevent any dampness from coming up through the floor.
2. provide a physical restraint against any drop down of the insulation should seasonal shrinkage occur in the joists etc.

Using the existing floorboards in these circumstances should be perfectly good , some extra screws through floor to joists, should provide a solid base to work from...pinenot

 

[46philh]

Should we go with subfloor as ...

1.WBP ply
2.PTG Floor
3. Steico 2400x600x18 Flooring Chipboard MR P5 TG FSC
4. Steico 2400x600x22 Flooring Chipboard MR P5 TG FSC
5. Steico 2400x600x22 WeatherDek2 Chipboard P5 TG FSC

 

[pinenot]

As I said in MY reply, you should have no reason not using the existing, but are you saying there's a problem doing this? ...pinenot

 

[Whitling2k]

I would only replace the floor if you need to. signs of wet/dry rot, wood boring insect etc?

I'm speaking from experience - I am just replacing a technicolour floor - 1/3 woodworm infested floorboards, 1/3 damp/ 22mm water proof chipboard (supported by woodworm infested noggings) and add a few rotten, shattered and unsupported T&G flood boards with glued 22mm Caberfloor P5 T&G chipboard.

It's quite an easy job doing the actual floor it's self - whats taking time is improving my electrics, walls, plumbing, heating, networking, replacing all the noggings with treated timbers, treating their end-grains... all "whilst the floor's up"

Going off topic here - but the Black and Decker electric drill-driver that dies after approx. 20 80mm screws isn't helping the cause (bought a Bosch PSR18.2 LI today so fingers crossed )

 

[46philh]

As I said in MY reply, you should have no reason not using the existing, but are you saying there's a problem doing this? ...pinenot

Sorry did not explain. In the new extension it will need a sub floor so looking for best material / budget for that ?

however since post the topic we have discovered part of the existing house has wet rot timbers so will need to replace some of current.

//www.diynot.com/forums/building/water-under-the-house.395383/ (Yes now struggling with the stress of all this)

 

[pinenot]

Oh well, better to find out now than later when the new floors down eh! and your sure it's wet ROT not just wet and requiring drying.
Further to the condition noted above, you should find out what the cause is/has been...pinenot