Drying timber

[Kalle B]

I'm thinking about cutting down some spruces and sawing them into beams for an upcoming garage construction. But drying timber isn't so simple, I suspect. From what I understand, it shouldn't dry too quickly, or it will crack. What's the best way to do it? Debark them first, I suspect, but then what? Cold/warm outside/inside? And how long should one expect it to take?

 

[Kalle B]

I saw before I dry, then?

End of July, would it be too late in the year? And let them lie until May-June next year?

 

[Fein]

You don't need to debark. Cut down the trees, saw them into the dimensions you want, and add a few % for shrinkage. Stack them with 25mm spacers between layers, stack narrow and high rather than low and wide (to apply pressure on the boards so they don't warp during drying). Don't stack against a sunny wall. Cover with something against rain, but keep it airy. Don't wait too late in the summer/autumn, high humidity can cause mold.

Expect cracks at the ends, which can be sawed off later. It may be minimized by painting the ends of the logs before sawing with some kind of sealing paint, although I haven't tried this.

I'm no expert, but that's how I do it.

not an expert either but Doesn't wood dry through the end grain? I know that's true with firewood, the shorter the pieces, the quicker they dry. it must be a very long process if you cover it up.

 

[Kalle B]

Many valuable tips here, I thank you humbly.

 

[Milkshaken]

hello..... Everyone knows that the lawn needs to be mowed 2 times a week and that the wood dries fastest BEFORE MIDSUMMER.... that's how it is... if you want quality timber, it should be sawed in April,,, then air-dried through, Stabbning... to be later used for its intended purpose.....

 

[Kalle B]

Well, I have never ever managed to finish the firewood before midsummer, but it has warmed well all winter for that ;D

 

[Karin_Lindhagen]

Shouldn't the trees preferably be cut in the winter as well to contain as little sap as possible already when the drying process begins?

 

[Ubbe]

However, the logs should never be dried because drying cracks should be avoided. That's why the logs are watered at the sawmills.

Drying cracks occur in the lumber dryer if the wood is dried too aggressively.

Unsawn timber does not crack more than a few centimeters in from the end grain. Watering is done partly to keep insects away and partly to prevent the timber from drying. The problem that arises when the timber begins to dry is that it becomes impossible to hit the right measurements during sawing.

When wood is sawn, you have to add a number of mm in "drying allowance," i.e., compensating for the wood shrinking during drying. If the wood you are sawing is already dry, it will not shrink at all as expected, and the measurements will be completely off for the dried wood. In practice, it often happens that a log that has been lying for a long time (e.g., windfalls) has started drying from the outer surface inward and thus has a varying moisture content. When this is then sawn, the shrinkage will also be varying... Planks often end up wedge-shaped with both widths and thicknesses that vary. A board that should be 25mm may be exactly 25mm at one end but a whole 28-29mm at the other end... It becomes impossible to use if precision is needed...

Regarding pith cracks, the secret is to saw along the pith. If this fails, you will almost always end up with a crack from the pith outward.