Shrinkage

[Backwoods Savage]

An interesting idea was proposed to me by a neighbor. We were talking about one of my wood piles and talking about seasoning. I mentioned to him that even though most of the stacked wood was ash that was dieing, I stacked it approximately 54" high. By fall it was down to about 46." (I forgot to write down the 46". I think that is right but will measure again today and write it down this time.) At this point he said that if I measure that wood pile in late summer it will have expanded.

Now there is something I never considered but I do not think he is right. His theory is that in his house there is a spot where the floor will separate in the winter but when warm weather comes it will expand back. My thought is that he is comparing what happens in an enclosed environment vs. the wood which is always out in the weather. Heating the home in winter dries the air further (otherwise nobody would have humidifiers) which causes his shrinkage. Then when he quits heating and yes, more humidity in the summer it goes back. I do not think this would happen to any great extent in the wood pile. However, I am going to do some measuring from time to time.

I can say for certain that the wood pile is the same height now as it was last year when I measured in September and December.


Has anyone ever done experimenting or keeping track of their wood shrinkage like this?

 

[smokinj]

the stacks will shrink in the summer.....I always think someone is steeling it! lol

 

[Backwoods Savage]

Jay, naturally they will shrink the first summer. We are talking about the second or third summer.

 

[quads]

I intentionally stack my freshly cut/split wood 4 1/2 feet high. That way within the first year it shrinks to about an even 4 feet tall. After the first year, it never moves again, and it certainly never goes back up any.

 

[smokinj]

Jay, naturally they will shrink the first summer. We are talking about the second or third summer.

I still say shrink if it swells its going to be in the wet spring or fall. jmho

 

[firefighterjake]

All I know is that my wood definitely shrinks as it gets older . . . and in the cold . . . especially cold water. :bug:

 

[Jags]

Dennis - I don't think you are gonna have a "re-hydration" (swelling) of the wood to a measurable degree. Follow me if you will: The majority of shrinkage comes from the internal cell walls loosing their moisture (seasoning - to us wood burners). Relative humidity cannot really "re-hydrate" those cells. For one, the cell walls have been damaged due to the drying process and two, the water got there when the tree was alive and "pumped" it into the cells.

If you kept it in a bucket of water - probably. Depending on relative humidity to do it - probably not.

 

[webie]

Seen the title ws thinking Stienfeld

 

[rdust]

I was in the pool! Oh wait, never mind we're talking about a different kind of shrinkage.

 

[70marlin]

I don't know about shrinkage. But the ground heaved and tipped over my wood pile?

 

[Wood Duck]

I have piles that shrank a lot in their first summer, and I have not noticed any increase in height since then. I believe that wood, once it is seasoned, reaches an equilibrium with the air, which makes the wood dry out a little when the air is dry, and regain some moisture when relative humidity of the air rises again. I don't think the increase in moisture is a lot compared to the amount in the wood before it seasoned, and I don't think it is enough to notice a change in the height of the stacks. just my guess...

 

[EatenByLimestone]

Ponder the thickness of his floorboards and the splits in your stack. What he is seeing is the floorboards returning to normal equilibrium. They are artificially dried over the winter by his furnace. It's just like a kiln. Since his boards are thinner they are going to be a bit quicker at returning to the equilibrium.

Your splits are thicker so they are a bit slower to change, either dry out or rehydrate. Since they are stored outside they are always at equilibrium. Now if equilibrium is really wet, they could easily pick up water, but will not show it as fast as a floorboard since they are so much thicker.

Matt

 

[michaelryba]

Two thoughts:
I think a lot of what a woodburner would call shrinkage is really just the pile settling. Gravity, time and the occasional gust of wind will eliminate some air gaps over that first year.
I agree with previous posts about the indoor lumber being unnaturally dry from heating. I think it does absorb and "grow" in the spring, but only to the more natural "equilibrium" level. Just to throw out some numbers for illustration: His house lumber would go from 10% water in winter to 15% water in summer. However, your woodpile never got to 10% in the firstplace, so it would stay at a 15% level all year long.

 

[Backwoods Savage]

Two thoughts:
[b]I think a lot of what a woodburner would call shrinkage is really just the pile settling. Gravity, time and the occasional gust of wind will eliminate some air gaps over that first year.[/b]
I agree with previous posts about the indoor lumber being unnaturally dry from heating. I think it does absorb and "grow" in the spring, but only to the more natural "equilibrium" level. Just to throw out some numbers for illustration: His house lumber would go from 10% water in winter to 15% water in summer. However, your woodpile never got to 10% in the firstplace, so it would stay at a 15% level all year long.

With all due respect, I do not hold to that theory. While some piles indeed will settle (look at some of the pictures posted from time to time), most of the shrinkage is still due to moisture loss. I could compare some of our piles over the years and there just is not much if any "settling" but lots of moisture loss which is shrinkage.

 

[wooddope]

I'm not a scientist, I don't even play one on tv, but I've noticed my pine woodpile seems more responsive to humidity changes than the hardwood pile.Once the pine is well seasoned and the weather is dry with low RH the pine is very light and clinky.However, if the weather turns muggy, the pine becomes heavier and feels wetter.The hardwood pile seems more consistent or, due to the pieces weight, is not as noticeable.Could this be due to the differences in cell structure or density?Oh boy,I'm in really in over my head now!Just my observations.

 

[Battenkiller]

Going from 54" high to 46" because of shrinkage of the wood alone doesn't correspond to any tables that I am aware of in the wood industry. No wood should shrink 15% in any direction, no matter how dry it gets. Your stack height shrinkage probably amounts to settling as well, as Pondman pointed out.

 

[heus]

Seen the title ws thinking Stienfeld

Me too. George Costanza!

 

[SolarAndWood]

I only stack on concrete and asphalt and see upwards of a foot after a year with 10' stacks. It led me to change my game and leave it outside in the heap longer as that amount of shrinkage combined with my lack of stacking competency leads to instability.

 

[BrotherBart]

Wars used to break out over this subject on the old forum.

 

[golfandwoodnut]

As George would say, "It just does". Shrink that is. Wood Floors will shrink and expand minimally. I think wood piles just shrink, look at the HH theories where you can put a stick at 10 feet and when the top reaches 8 feet, you know it is seasoned. I know my HH has shrunk considerably, although I did no exact measurements.

 

[bogydave]

Well I know my pile shrinks more in the winter than in the summer.
Last years pile totally disappeared.
I finished the winter burning some dead fall spruce.

Alaska's winters are good at drying wood, never measured to see how much shorter the pile is due to drying though.
8" would be noticeable, I stacked it in the wood shed into the rafters.

Something I'll watch this year

I'm just hoping it don't expand & lift the roof :bug:

 

[Backwoods Savage]

Going from 54" high to 46" because of shrinkage of the wood alone doesn't correspond to any tables that I am aware of in the wood industry. No wood should shrink 15% in any direction, no matter how dry it gets. Your stack height shrinkage probably amounts to settling as well, as Pondman pointed out.

I answered this post in the other thread, but here goes again:


Very interesting. Now please observe this picture very closely. Look at the very end of the stack that that ugly man has his hand on.

Now someone please describe for me exactly where and how the end of the stack has settled. The measurement was actually taken on the opposite side of the stack and it was measured from the bottom of the bottom split to the top of the top split. Notice I did not measure from the ground up because the saplings that the wood is stacked on have probably settled into the ground a bit.

 

[bogydave]

please describe for me exactly where and how the end of the stack has settled. :

Maybe somebody is taking a layer off the top each stack & making a new stack.
Have you counted your stacks lately. LOL

Looks good to me. That just seems like allot of shrinkage.
Since you measured it with the same tape, I believe it.
Wood shrinks, that's a fact. each of your splits shrinks about 3/4".

Going to watch mine & see how much they shrink, more curious about it than anything.
I bet every wood type has a different shrink ratio. I have birch & spruce.

BTW: VERY Nice stacks

 

[SolarAndWood]

You will get a good display in your shed Dave. No doubt in my mind after jamming it tight against the ceiling and seeing how far it drops.

 

[Battenkiller]

each of your splits shrinks about 3/4".

I bet every wood type has a different shrink ratio. I have birch & spruce.

Not to offend, but I sincerely doubt that. Since these threads are already crossing, I'll post the table of wood shrinkage I posted on the other thread. Your woods of choice are highlighted in green.