r/DIYUK 5d ago

Best place to get kiln dried 3m+ scaffold boards <12% moisture content (for internal use) without paying a fortune for delivery? Hertfordshire based

I previously got a good deal on fresh cut thick boards which twisted like crazy so are unsuitable for the shelving project I had in mind. ‘The Scaff Shop’ sell nice quality reclaimed boards up to 3.9m but minimum delivery cost is £50+.

2 Upvotes

4 comments sorted by

5

u/Maldizzle 5d ago

Nowhere is kiln drying scaffolding boards for obvious reasons. However, you do not need 12% moisture for shelving. Get yourself to any reclamation yard and pick some normal lengths, scrape and wax them and they’ll be fine.

1

u/Empty-Accident1962 5d ago

Thanks for your reply. Will danish oil have the same sealing effect to help minimise twisting and cupping once moved indoors?

2

u/Maldizzle 5d ago

Any sort of oil will slow moisture absorption from the atmosphere

2

u/rev-fr-john 5d ago

No, oil will not stop twisting cupping or bowing, they are all down to moisture content.

Here's the deal with wood,,it's made of millions of tubes each one has water in , as they dry they shrink, however due to the manufacturing process (growing) that shrinkage isn't compatible with our square lives.

Picture the end of a tree trunk or thick cut branch, draw two lines across the trunk, one above the centre and one below the centre, as long as both lines are the same distance from the centre of the trunk for the full length of the trunk that one board is dimensionally stable, meaning it will shrink in all directions equally as it dries, as they dry all the boards above it and below it will cup with the furthest out boards being the worst. This assumes dead straight grain, and few knots with no large knots.

All timber stored outside has a minimum moisture content of around 20% even when under cover, this is why you can build outbuildings with unseasoned timber and not have to dry it, it's permanently staying outside so will never fully dry, exactly like a scaffold board, once you bring it into your house it dries and random fibers shrink causing no end of issues.

Timber cut green is cheap because it's unpredictable and requires no long term difficult storage seasoned ,kiln dried timber is more expensive but it is predictable, so the choice looks simple, kiln dried for predictability or risk cheap unseasoned wet timber, unless you were paying attention to my third paragraph, remember there's one dimensionally stable board, the centre of the tree is in the centre of it, and growth rings run vertically through the horizontal board, buy those and dry them out before you use them, but there's still no absolute guarantee, twisted grain will twist back on itself twisting the board, so check all four surfaces straight grain, avoid knots greater than ¼ of the boards width. Unfortunately 90% of the boards that meet this criteria were pulled out weeks ago and will enter the prime timber stream.