On 5 Apr, 09:12, "JWBH" wrote:

I was going to nail
them down, but was advised by neighbour to screw them instead, since he says
nails can work loose.

Not bad advice.

If it's 100 years old and uses real floorboards, then you can nail
them down successfully so long as you use real floorboard cut nails
(just ask in any real builders' merchant). If you use typical wire or
oval nails, they'll work loose.

OTOH, screws work, screws work in modern flooring materials, and
screws are easily removable. If you might ever want to lift the board
to gain access for pipes, use them. Use modern parallel screws, such
as Screwfix's Goldscrews. Lubricate with candlewax if you want
(better ones are pre-done) but don't use soap or PVA as that's more
likely to cause rusting, jamming and snapping.