Leveling Floor Fastening Advice

[Jase1976]

HI,

I'm levelling out a floor in an old (120yo) terrace. It's the upper landing floor with a span of approx 1m and it drops just over a cm.

A stud wall has been built up over the furthermore joist, so will be trimming the boards flush to the joist and fastening some 50mm x 25mm timber to increase the height.

Could someone recommend a screw for this job? And what pattern should I use when screwing together. Obviously I only have access from one side.

Many thanks in advance!

 

[oldbutnotdead]

I'd not be bothering myself for 10mm in a metre but if you really want to.... you're planning on fixing roof battens to the side of the joists to level the floor up? Bit of a shoddy way to do it but some decent 2" x 8 screws (Reisser or something similar that will bite properly and don't need piloting) and stick them in at 6" centres ish alternating high and low on the batten. And then sell the place.

If you're planning on living there then do it properly and pack the joist tops- use some 10mm shuttering ply on the highest one, put a straight edge across the rest and use ripped bits of hardboard and/or felt support trays (my favourite shims- £2 for 1500mm x 400mm of 1mm shim, bargain) to bring them to level, fix them to the joist tops with panel pins. Much better job since you're then working in compression rather than applying torque.

 

[Jase1976]

Thanks for the reply...

I'd rather do it properly to be honest (even though I am selling anyway - I like to do things as best I can).

Reading through your second paragraph, how do I pack the joist top of the lowest joist when it has a stud wall on top of it? The only reason I thought 'sistering' the lowest joist was the way forward was because packing wasn't an option. I do plan packing the joists in between the highest and the lowest, but couldn't think of another way to do the lower one?

Happy to listen to any advice offered so thanks again.

 

[oldbutnotdead]

Aah yes of course, the boards will be hanging at the wall end won't they?
I'd go for 3 x 1 screwed to the joist rather than 2 x 1 but still with the good screws (not the cheap ones- they won't pull your support board into the joist). Again zigzag them at 6" centres, the bottom screws will be doing most of the supporting, the top screws will be preventing the 3 x 1 rotating away from the joist. If the sole plate of the stud wall is in line with the joist then screw into that as well- the higher the top screw the better. If you're packing the rest then the loading on that last element will be pretty low.

 

[Jase1976]

Sorry if I wasn't totally clear in my op - yes, the boards would be hanging at the stud wall.

3x2 it is then - and will fix as you describe.

Perfect! Thank you so much for your time!

 

[oldbutnotdead]

You can use 3 x 2 if you want but you'll need longer screws....... 3 x 1 will be fine, the joists you're fixing to are doing the hard work of spanning x metres, all you're doing is raising floor level a bit. And again for 10mm across a metre the benefits are questionable, if you have to lift nailed boards then you'll almost certainly split one or more. odds are even worse if they're tongue and groove.