Is drying wood indoors ok?

[Niels J. Larsen]

I have the opportunity to buy some 2½" walnut planks, that have been cut about 2-3 months ago.

Will it be ok to stack them inside my shop (constant temp about 20c) or will I have to let them dry outside for about 2yrs before taking them inside to dry further?

I'm worried that the heat and dry climate in my shop will make the planks warp and crack etc. Am I right about this?

Thanks
Niels

[Bob Genovesi]

I cut and dry wood in my shop on a regular basis. Having said this I'm talking about 25 to 30 board feet at a time.

I store them up high spacing them apart with 3/4 scrap. I've never had a bad warping issue but all wood after it's cut into plank will warp and twist a little.

[John Keeton]

I think the wood will be fine, although rapid drying can cause a little more movement in my experience. But, not knowing your climate, introducing a significant source of moisture in the air of your shop could cause an issue with your tools - lots of factors at play here, including temperature, relative humidity, tightness of your shop, etc. You do not state the quantity of wood.

[Niels J. Larsen]

Well, the climate here in Denmark is generally on the dry side and my shop is a separate building which is insulated almost to normal building code.
This means about 300mm of foam insulation in the concrete floor, 300mm of fiberglass insulation in the ceiling and about 150mm fiberglass insulation in the walls.
I have the gas heater for the house located in the shop and this gives off enough heat (from tubing etc.) to keep the temperature at a constant 18c.
The moisture content is also stable at about 45-50%.

I'll be buying 23 planks of 2½" walnut, 4ft long in different widths ranging from 6" to 18".

If you think this will introduce enough moisture to cause rust on my machines and tools and/or heightened moisture levels in the dry wood that I already store in my shop I am concerned.

Will this be the case?

[Julian Nicks]

Stack and sticker them, put anchorseal on the ends, and you can even add a fan to aid in air circulation. If there is a good amount of boards, watch out for the excess moisture rusting all of your cast iron surfaces. Another good idea is to put the boards in your attic. It will act like a kiln. Don't forget no matter where you stack the lumber to weight it down to help keep it from twisting.

[Niels J. Larsen]

Stack and sticker them, put anchorseal on the ends, and you can even add a fan to aid in air circulation. If there is a good amount of boards, watch out for the excess moisture rusting all of your cast iron surfaces. Another good idea is to put the boards in your attic. It will act like a kiln. Don't forget no matter where you stack the lumber to weight it down to help keep it from twisting.

Thanks for the suggestion Julian. I didn't think of that!

I'll put 'em in the attic and by the time it's dry I've probably forgot about it... :rolleyes:

[Chip Lindley]

Walnut is one of the easier woods to dry! 10/4 planks that have already seasoned 3 months will be fine to dry in a shop building. But, I have to wonder if putting them in an attic's heat might be too much, too fast! Sometimes More is not Better, concerning lumber-drying!

Anyone have a schedule for length of time to air dry before kiln drying lumber?

[Julian Nicks]

Generally you want the wood to be around 12-15% before putting it in the kiln, which equates to 3 months air dried for 4/4 in the midwest.

[Cliff Rohrabacher]

It's preferable. No bugs, no rain, no wild swings of humidity, no soaring temperatures.

[Jim Becker]

It's preferable.

I have to respectfully disagree with that. Initial drying is generally considered best done outdoors where prevailing air movement wicks away the moisture from the wood as it's expressed outward. Temperature, ambient humidity in the air, etc., don't matter much. A simple cover to keep standing water/snow/ice off is all you need. Once the wood gets to somewhere in the 12-15% MC range, moving it indoors (still stickered) is more workable, but there still needs to be good air movement. Personally, I leave it outside until it's "done". I've dried about, oh...3000+ BF here on the property with excellent results, both walnut and poplar.

[David Keller NC]

Well, the climate here in Denmark is generally on the dry side and my shop is a separate building which is insulated almost to normal building code.
This means about 300mm of foam insulation in the concrete floor, 300mm of fiberglass insulation in the ceiling and about 150mm fiberglass insulation in the walls.


Woah - 300 mm?!? That's 30 cm or 12 inches of insulation in the floor - it must get mightily cold in Denmark to make that a worthwhile endeavor.

You should be fine stacking the wood in a shop at 40-50% relative humidity because it's been setting out for 3 or 4 months. By this point, the "free water" in the wood should be gone. However, you will probably need to very thoroughly seal the end grain to prevent it from checking badly. That's usually not an issue with 8-12 foot long boards, but with only 4 feet, losing 6 inches off of each end from checking wouldn't be good.

[Cliff Rohrabacher]

Everything I stored out side I lost to dry rot, bugs, and other problems
The air carrying moisture away won't be any less efficient indoors.
That is so long as the "indoors" in question is not hermetically sealed.

[Niels J. Larsen]

Woah - 300 mm?!? That's 30 cm or 12 inches of insulation in the floor - it must get mightily cold in Denmark to make that a worthwhile endeavor.


Well, I didn't do the math, but there's really no choice - it's required by law. Remember I have radiant heat in the floor.

And no, it doesn't get mightily cold, but the reason for doing it is conserving energy instead of wasting it to heat the outside.

There are experimental houses being built using a "low-energy" concept where there's about 460mm of insulation in the roof and about the same in the walls. With active ventilation re-using the hot exhaust air in addition to "normal" heating, they can be heated for about $20 a month. Pricewise the house is only slightly more expensive to build compared to a "normal" one.

[David Keller NC]

Niels - I'm curious about this. 12" of insulation in the ceiling and 6" of insulation in the walls makes sense, but how does one go about getting 12" of insulation in a concrete floor?

Is this "embedded" insulation like the little polystyrene beads that are mixed with the concrete? Otherwise, I'd think the weight of a concrete floor would just crush a layer of "normal" insulation, whether it's fiberglass bat, rigid foam or some other type designed for walls and roofs.

[Niels J. Larsen]

David, what we use here is called "sundolitt" and you can see everything about it here: http://www.sundolitt.dk/upload_images/069A069E43644A518113F3705862CAC2.pdf

Sorry that it's in danish, but if the pictures aren't enough you can probably translate it using an online translator.

On top of that you place some spacers in which you place a steel mesh made of 10-12mm thick round bar with about 10x10cm squares. To this the radiant heating tubes are fastened.

On top of everything you typically pour a 10cm thick layer of concrete. When that's hardened you pour another finer layer which you level out etc. and THEN on top of that you can either put tiles, wood flooring or whatever you like.

[David Keller NC]

Interesting - It looks like dense styrofoam. Makes me wonder whether it's suitable to use as stickers in a lumber stack.

[Niels J. Larsen]

I think it all depends on how wide you'd make the strips and naturally how much wood you'd place on top of it :), but yes - I think it would fit the bill.

[phil harold]

I don’t know what the laws are in Denmark but I heard in Germany they build with the idea that a building is to last 300 years
something not heard of in the states.
By building a building that will last ages is green building in my eyes
making it energy efficient is just makes it better

And you got to love radiant heat

[David Keller NC]

I don’t know what the laws are in Denmark but I heard in Germany they build with the idea that a building is to last 300 years
something not heard of in the states.
By building a building that will last ages is green building in my eyes
making it energy efficient is just makes it better

And you got to love radiant heat

Yeah, we don't do things like that in the 'States - we allow things like "amish heating mantles" and (even worse) the "Cool Surge" portable air cooler that works on "just pennies a day". Of course, if you've got a science background you realize that the $200+ units are basically a fan that blows air over plastic ice blocks, and the power required to freeze those ice blocks is going to cost a lot more than "pennies a day".

There are definitely some characteristics of European society that are often cited as "restrictive" in the US. We could use a lot more of that restriction....

[Niels J. Larsen]

I don’t know what the laws are in Denmark but I heard in Germany they build with the idea that a building is to last 300 years
something not heard of in the states.
By building a building that will last ages is green building in my eyes
making it energy efficient is just makes it better

And you got to love radiant heat

We don't do that here in Denmark, and frankly I doubt they do it in Germany either.

Here in Denmark there's a separate building directive which is basically a set of rules on how you construct all aspects of a building. It's meant as a directive for the people actually doing the construction as well as a way for the people in charge of the build, to control that everything is being done correctly.
If you want to build a house (or shop for that matter) you have to make detailed drawings of all aspects of the building and send them to the local county, where they will be reviewed. Based on that review they are either approved or rejected with a reason so you know what you need to change.
There's also rules about where on the property you can place your buildings in relation to neighbors, public roads etc. as well as rules about how many square meters of building you can build on a piece of land. Usually you can place buildings on 25% of the land you buy.
Then there's a local regulation that may specify how many floors you build, what type of roofing, gutters, wall type etc. This is done to avoid a bright pink home or a 4-story building in the middle of all the other "normal" homes. When I write this I can see that it may come across as a bit like the old USSR, but it's really not that bad.
All of these things are ONLY for homes in a residential area. If you were to build a building for a business or a home in a agricultural area, other rules apply - and I don't know them well enough to describe them here.

[phil harold]

We don't do that here in Denmark, and frankly I doubt they do it in Germany either.

Here in Denmark there's a separate building directive which is basically a set of rules on how you construct all aspects of a building. It's meant as a directive for the people actually doing the construction as well as a way for the people in charge of the build, to control that everything is being done correctly.
If you want to build a house (or shop for that matter) you have to make detailed drawings of all aspects of the building and send them to the local county, where they will be reviewed. Based on that review they are either approved or rejected with a reason so you know what you need to change.
There's also rules about where on the property you can place your buildings in relation to neighbors, public roads etc. as well as rules about how many square meters of building you can build on a piece of land. Usually you can place buildings on 25% of the land you buy.
Then there's a local regulation that may specify how many floors you build, what type of roofing, gutters, wall type etc. This is done to avoid a bright pink home or a 4-story building in the middle of all the other "normal" homes. When I write this I can see that it may come across as a bit like the old USSR, but it's really not that bad.
All of these things are ONLY for homes in a residential area. If you were to build a building for a business or a home in a agricultural area, other rules apply - and I don't know them well enough to describe them here.

So you can build a house with siding that will need to be replaced in 15 to 30 years? Hot air furnaces are designed only to last 20 years now in our area the builder only has to warranty his work for one year, and thus quality suffers

[Niels J. Larsen]

So you can build a house with siding that will need to be replaced in 15 to 30 years? Hot air furnaces are designed only to last 20 years now in our area the builder only has to warranty his work for one year, and thus quality suffers

Well yes - and no. If you build a house either completely and wood or only with wooden siding I wouldn't expect all of the siding to last more than 30 years. Naturally you'd maintain it with some kind of surface treatment but I would expect that the side towards the south would be at least partially replaced.

15 years sounds a bit too early for me, but again it all depends on what type of material you choose for the siding.

[Curt Harms]

We don't do that here in Denmark, and frankly I doubt they do it in Germany either.

Here in Denmark there's a separate building directive which is basically a set of rules on how you construct all aspects of a building......

from the zoning and BOCA codes although it may be somewhat more restrictive than where I live. I suspect we'll see higher energy efficiency standards in new construction, it's a one time cost at construction time vs. paying for not building for energy efficiency every month for years and years.

[Tom Sontag]

Back to the original question: I do not worry about the walnut at all since walnut is so well behaved and dries without much worry or effort. I think the real question here is what the excess moisture might do to everything else in the shop. If the building is sealed I could see the moisture causing rust problems quickly; wet wood holds lots of water.

If you leave a window open or find some way to circulate fresh air daily then I think it would go just fine.

Occasionally this drying indoors question comes up and with difficult woods degrade can happen, but the effect on the indoor environment is ALWAYS my first concern. I know people who lost their house to toxic mold; you do not want to saturate your indoors with water for weeks at a time.

Niels: keep fresh air exchanging regularly and you will be okay. If you ever walk in and sense the humidity then things are not right for your shop.