wood: splits in floorboard

[Stephen]

Hello,

I asked my local timber merchant to plane down a few lengths of 5x1 to replace some floorboards. I didn't have a close look at the time but they seemed ok when I bought them. I've come to fit them and I see there are some cracks along the surface. It's hard to tell how deep they go; they certainly don't go all the way through the wood. What has caused these?

Have I stored them at the wrong temperature or wrong humidity? They have been kept cold but dry. Will they be safe to use as floorboards? I don't want them breaking beneath my feet!

Thanks.

[The Natural Philosopher]

Wood splits naturally on drying. simply because tangential shrinkage is about 3 time radial shrinkage, and heartwood generally doesn't shrink much at all.

The aim of commercial timber producers is to reduce it to the minimum, and for quality cabinet work, to zero.

You do that by cutting it ito planks, an reducing moisturee content slowly. Then overdrying it in a kiln, and then leaving it to harmonise with whatever its stored at.

Softwood, being cut from generally smaller trees so each board spans more of the original trunk is very prone, and it also has serious growth rings, due to high and variable growth rates, which alter the properties across the ring stricture.

In short, it is crap by and large. which is why only idiots use it for anything but structural work, where it doesn't matter.

You probably got structural wood planed down. That's what its like.

They

Oh they wont do that.

They will just look what any softwood floor looks like. crappy. ;-)

And if not protected will wear into grooves as well.

[Cash]

The natural process of drying out.

If thet are around 3/4 of an inch (20 mm) thick, it's very unlikly that they will "break beneath your feet" even if they are quite badly split.

What you should now do, is place the boards in the room where they are to be laid for a few days to 'acclimatise' them - in other words, to get them down to the right moisture content and allow them to shrink (and probably bend) before laying - let us know if you get a board that looks like an aeroplane propellor as these are very interesting to lay. LOL

Cash

[dom]

Cracks along the length of the boards and on one face only?

Look at the boards end on and see if they're cupped. Look at the grain pattern on the end - is the grain relatively flat or quite curved?

Boards cut from near the centre of the trunk are more prone to cupping (and consequently cracking on the convex face), whilst side boards are less prone (but more expensive).

Are they tongue and groove or square edge boards? (t&g have the tongue slightly off-centre and should be laid so that the tongue is nearer the bottom).

If not t&g, can you lay them with the cracks facing down? Good practice is to nail them with the cups facing upward (cracks down) so that the nails tend to pull it out of cup.

Don't worry about board strength if the joists are good, & correctly sized & spaced.

[Stuart Noble]

Softwood from northern latitudes doesn't have high growth rates

Ah. I see we're in dogmatic mode today

[meow2222]

Most unlikely to break. Even if theyre split right through before laying, theyre easily repaired with a bit of metal strip screwed to the underside.

NT

[Stephen]

Yes

I'm not sure not you mean by cupped. Do you mean that the wood is curved? It's not curved but of course, it went through their planer. The grain is quite curved at the end.

Square edge just to replace one section of one board I lifted out.

Sorry for the late reply and thanks for all the reassurance. I guess it dried out too quickly once I bought it inside.

[Stuart Noble]

Don't blame yourself. It was rubbish timber. Good stuff should shrink without twisting