Pine T&G Floorboards - secret nail advice

[rarara]

Am going to lay new 20mm x 118mm wide pine boards onto the existing original floorboards, but have a few queries....

1) Will it make much difference if the new boards are going to run parallel to the existing boards?

That way they will be perpendicular to the joists. The main reason to do it this way though is that the boards (4.5M long, and the room width is 4.3M) can be laid whole, rather than having a bunch of staggered boards, cuts etc when laid along the 6M length of the room.
​

2) What sort of fixings to secret nail the tongues?

The boards will be fixed to the boards underneath, rather than to the joists - for that thickness what sort of fixing, if I was to say hire a pneumatic nail gun? I don't want floating or glued - I want the most sound and stable possible.
​

3) If I hire a nailgun I may take the opportunity to fix a floating maple hardwood T&G floor in the hallway which creaks like laminate when walked on. It too is approx 20mm thick - can the same nails be used as for the pine?

 

[Burnerman]

Before you get stuck in.....
Expect new boards to shrink quite dramatically if they aren't left to acclimatise - and they should be fitted with the help of floorboard cramps.
May I ask why you are putting new boards on top of old, rather than replacing the originals?
John

 

[rarara]

I searched for new boards which are dried to a lower MC, so I am expecting any shrinkage to be with acceptable limits. Are floorboard cramps not attched to the joists, so not an option for me?

New on top of old as I am looking for the extra sound insulation provided by both layers of boards (as well as a layer of 2mm HD soundproofing rubber). Downstairs neighbours are musicians

 

[Burnerman]

Yes, floorboard clamps are secured to the joists when in use....bloomin' good they are too - I had to use large ply wedges in my day.
Others may comment on the noise situation - you have every sympathy! I don't know whats best (maybe acoustic insulation but that means floor up) but noise loves to come through gaps.
Presumably you aren't concerned about a step up into the room, and the door fitting?
The last floor I did - I left the new boards to acclimatise for a month (in the same room - it was the whole top floor) before I laid them -and they still shrunk a little, but not so bad to make a fuss.
Others will advise on the nailing - I've never owned a nail gun.
John

 

[gregers]

hire or buy 1 of these,

 

[rarara]

any idea what nails/pins though for 20mm pine and/or maple?? Do they fire in at 45 degrees? If so, then I think 50mm would give a depth of approx 40mm, so would be through the board and through the sub-boards with a tiny bit to spare - does that seem OK?

 

[tony1851]

You risk splitting the tongues if you try secret nailing.

 

[rarara]

You risk splitting the tongues if you try secret nailing.

should pilots be drilled, screws used or should it be face nailed/screwed instead? the data sheet for the timber suggests screws to the tongue, but the suppliers confirmed nails would be fine