what size of screws for old floorboards?

[JohnD]

I have lifted some boards in an Edwardian house. I have taken up the ones that have obviously been lifted by past generations of gasmen, plumbers and electricians. Boards appear to be 4" x 3/4" and were originally held with cut nails, now the lifted sections have been lightly tacked down with an assortment of French wire and panel pins. In most cases, the cut nail heads have pulled through the boards with varying damage and the boards were already pretty loose. Some of them have been cut and the cut pieces only span between two joists along a passage. Joist sizes are mostly 8"x2", some 12" x 3" possibly to support partition walls or because of spans.

I was thinking of drilling and countersinking the boards, and pilot drilling the joists, am wondering what would be the "proper" screw size. I was thinking 1 1/2" x 8 (35mm x 4.5mm is it?) but maybe this would not be big enough?

 

[big-all]

yep if thats what you have although 1 3/4 " would be the ideal but 1 1/2 is fine

but have some 2x1/4" handy for where the nails have left a large hole

all pipes and services should be at least 2" from the surface so mark any area where they arnt