UKC

We're buying some reclaimed wooden floor boards for one of our rooms and we are trying to work out how much to buy.
The floor is 32m2 and the joists have 60cm centres. is there a rule of thumb we can use to work out how many extra m2 we'll need by the time we cut everything to length etc? Or does it depend completely on the floorboard length and width?

Ta!

In reply to MeMeMe:

Depends on the lengths. If you guessed at losing 0.4m off every length. Guess at the average number of joints along the length (say 2?). You will lose the width of room x 2 x 0.4m. Something like 4-5m2.

600m centres is quite wide. Make sure the boards are 20mm+ thick.

In reply to sbc23:


60 cm between joists is massive, the floor must be bouncy as hell.

In reply to sbc23:


I think you'll need something a bit thicker than 20mm to span a third of a mile!

In reply to gethin_allen:

Possible loft conversion? Modern trusses are usually at 600mm c/c.

In reply to MeMeMe:

32m2? That's massive. Did you miss a point out? 3.2m2 by any chance?

In reply to RockAngel:


No it's not, but 3.2m2 is very small. My living room is over 40m2 and I wouldn't say it's massive.

In reply to MeMeMe:

Normally around 10% waste allowance.Depends on the quality of the reclaimed boards.Span between joists is quite wide.Probably best to overboard joists with 18mm ply or chipboard then glue/nail flooring to the ply/chipboard.

In reply to Wsdconst:


Your living room may well be 40 square metres, I very much doubt it's 40 metres square!

In reply to Fraser:


I was thinking that, 600 mm between ceiling joists or studs in a stud wall but not in a conventional floor

In reply to sbc23:


Yup, we're looking at 22mm boards so it doesn't bounce.
We built the floor and chose 60cm centres because it's a relatively low ceiling in the kitchen underneath and the beams are exposed and 60cm centres just looks so much better.

I think in the end I've decided it really depends on the length of the boards, with short boards that don't divide neatly by 60cm there's loads of wastage but if the boards happen to be the right length then there's hardly any!
Unfortunately the eBay adverts for boards don't tend to specify board length.
I guess we'll assume 10% for pricing up and then we'll have to measure up more carefully when we actually order.

If anyone got a recommendation of where to get boards? Just looking on eBay at the moment.
We don't mind having to sand them down ourselves (well, we'd rather not have to but if it's cheaper we will!)

In reply to Oceanrower:


Just to remove any doubt the room is 4m x 8m, not 32m x 32m! So it's a pretty big room but not ridiculous!

In reply to Speed Reed:


We'd thought about this but thought it would just be adding expense, but now I think about it it would mean much less wastage and we could also use thinner boards.

In reply to MeMeMe:

I hate to throw a potential spanner in the works, but did you get a building warrant (or an engineer certify) for the load-bearing floor having joists at 600mm c/c? I think even 22mm boards may be a bit springy at those relatively wide centres.

In reply to Fraser:

I'm no tradesman , but that is what I was thinking.

Could he put noggins across the joists to stiffen it up ( or perhaps screw a 5mm layer of Ply down first before laying the boards?)

In reply to gethin_allen:


They're about that far apart (though very unevenly spaced) in my 30s terrace with 20mm softwood boards on top. The floor's springy/soft in places but mostly where joists have been damaged one way or another.

Assuming the room is square then you need ~5.5m boards so at least one join, probably averaging more like 1.5 joins/board for a complete run. If they're genuinely random lengths you'd expect to be throwing away on average 600mm-900mm per full board run so between 10 and 15% waste. Could be much worse if they're all similar lengths and happen to be just too short for your application meaning each needs a big cut to match your joist pitch and one needs a long chunk thrown away because it's too short to be used in the next run. Probably also worth factoring in cutting out damage, splintered nail holes etc if they're anything like the ones I pulled up.
jk

In reply to MeMeMe:
If you are worried about the loadings as pointed about above, TRADA span table gives joist size for 4m span, 600mm centres, intermediate floor (gk=0.5kn/m2, live load=1.5kn/m2) as 220x63mm with minimum bearing of 80mm at each end. That's 9x3"s on big joist hangers.

Worth a check before you board it and dynamically test your bed.