19mm T & G over existing floorboards

Hi,

I have done a search, but could not quite find what I was looking for.

We are going to be having 19mm T & G Karri boards installed in the near future.

We currently have Baltic Pine boards running through the house, which have been mutilated quite a bit by previous owners (obviously lifting boards to access sub-floor/ceiling cavities, etc), hence the new boards. The existing boards are structurally good, i think they are 22 or 25mm thick, and would provide a good base.

We want to run the new boards in the same direction as the existing boards, so the way I see it is that we have 2 options:

1. Install 4mm ply over existing boards, and lay new boards over the ply.
2. Remove old boards, lay red tongue sub-floor, and lay new boards over sub-floor

If we go for option 1, we don't want to go for anything thicker than 4mm ply, as it will raise the floor too much. Does this seem like a viable option? Will it present any problems down the track, with movement, etc? We are on a fairly tight budget, so this is a more attractive option, if there are unlikely to be any problems down the track.

If option 2 is the go, I will undertake to remove the old boards and install the sub-floor. Are there any tricks/traps to laying the sheet flooring? I'm a bit unsure about how to deal with removing re-laying the floor at door jambs, and where the floor and walls meet (if that makes any sense?). Is the r/t merely top nailed to the joists? Would a coil nailer be the go?

The area is roughly 100sqm over ground floor and 1st floor.

BTW, the new Karri boards are being installed by the supplier, who recommended option 1.

Any input appreciated.

Thanks,
Jonty :2tsup:


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