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View Carloz's profile

Why is 2x4 so wet?

by Carloz
posted 05-20-2017 04:09 PM


22 replies so far

View Woodknack's profile

Woodknack

12399 posts in 2554 days


#1 posted 05-20-2017 04:31 PM

Trees have water inside. That water will dry up naturally but it takes time. So mills put the lumber inside a kiln which removes moisture faster. Hardwood is dried down to 8-12% while construction lumber is only dried to around 18%. So you’re right, it isn’t rain.

-- Rick M, http://thewoodknack.blogspot.com/

View Carloz's profile

Carloz

1147 posts in 765 days


#2 posted 05-20-2017 04:35 PM

It is not 18% . It is more like (judging by the weight) 50%

View TravisH's profile

TravisH

621 posts in 2109 days


#3 posted 05-20-2017 05:16 PM

I think all the products I come across at HD are either framing lumber & stud (kiln dried) or exterior pressure treated products. Never have come across “wet” framing lumber/stud material as it would be worthless for its intended purpose do to mold issues, loss of product before use, etc..

Only time I have seen “wet” 2×4 are the pressure treated products. Typically a water based copper or sodium borate product. This solution will well up when driving screws or cutting at times in the fresher stuff that they put out. I usually sort this out and get the older stuff that has dried out more slowly in the store as no issues with the splitting. As mentioned they will dry out quickly and split, bow, etc.. quickly once brought home and laid out.

View SignWave's profile

SignWave

451 posts in 3209 days


#4 posted 05-20-2017 05:47 PM

I agree with TravisH. All the 2×4’s at my local HD are either KD or pressure treated. The pressure treated stuff was definitely wet and heavy, and dried considerably.

-- Barry, http://BarrysWorkshop.com/

View Rich's profile

Rich

3757 posts in 763 days


#5 posted 05-20-2017 05:47 PM


I think all the products I come across at HD are either framing lumber & stud (kiln dried) or exterior pressure treated products. Never have come across “wet” framing lumber/stud material as it would be worthless for its intended purpose do to mold issues, loss of product before use, etc..

I gotta go with Carloz on this one. I have bought much 2x lumber at HD that was physically damp to the touch. It’s not going to mold, since it’s in open air when you use it and it will eventually reach an equilibrium with the environment. There’s no loss of product, since wood doesn’t shrink significantly along the grain.

For a base to put my workbench slab on, I bought 2×4, 2×6 and 4×4 pieces at HD. They were literally damp to the touch.

Carloz, you’ll get two suggestions here — sticker and stack and let them dry a couple of months (and pray they don’t twist to the point of being unusable), or do your build to lock them in place.

I chose the latter for my base. I jointed and planed them to true the surfaces (purely aesthetic reasons), and did the build that day, using 3/8” dowels. I put 3 dowels in the 2×4 stringers that attached to the legs, and 5 dowels in the 2×6 aprons. That was about a year ago and it hasn’t budged.

Another upside was that my shop smelled like a Christmas tree lot for about a month after.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

View William Shelley's profile

William Shelley

592 posts in 1643 days


#6 posted 05-20-2017 05:58 PM

I can’t speak for home depots in other parts of the country, but in the pacific northwest, HD does not stock KD lumber longer than 104-5/8”. The KD lumber they carry: 2×3-96, 2×4-92-5/8, 2×4-96, 2×4-104-5/8, 2×6-92-5/8, and sometimes 2×6-96. All other dimensional lumber is “green”. That being said, even “green” lumber should not be dripping water. I would have been more picky when purchasing the wood in the first place.

HD and Lowes source commodity items like lumber from different mills and thus sometimes one unit will be much wetter, or be a different subspecies of Fir, etc. If you look up in the racking next time you’re at one of those stores you’ll probably see units of lumber with different mill’s wrapping on them.

And, again I can’t speak for other stores but at the two home depot stores I’ve worked at, if the unit of lumber that was available to pick from was significantly not to your liking, you can ask for a new unit to be dropped. It’s up to the discretion of the lumber department associate and/or the manager on duty, but I’ve done it for people many times and it was the norm at my stores, if someone was legitimately unhappy.

-- Woodworking from an engineer's perspective

View sawdustjunkie's profile

sawdustjunkie

387 posts in 1891 days


#7 posted 05-20-2017 06:16 PM

I live in Wisconsin and we have the Menard chain.
The 2×4’s they sell all look like bananas. I have to go thru 30-50 to find 5-10 that I can use.
If I don’t use them in a few days, they will warp so badly, they just become scrap.
The Home Depot’s by me, seem to have better lumber, especially plywood and that is where I shop for wood.

-- Steve: Franklin, WI

View josephf's profile

josephf

204 posts in 2270 days


#8 posted 05-20-2017 09:57 PM

when i am first into the stack at lumber yards the lumber is often very heavy and wet .longer it stays that way longer it will stay straight and not crack . bums me to see someone pick through the pile and leave it all thrown up off the pile to get sun and air .just means yard has more junk wood they cannot sell .
the kiln dried comes at a higher price .if stack is outside they try to keep tarps on it though hope it sells fast enough . but even kiln dried lumber -2x stock isn’t really dried enough for wood working projects .expect some shrink .
the issue with the very wet wood is it can also cause problems with a house frame either when it dries and moves or dries and causes moisture issues [like mold ] in the project .
does that help .
if you buy kiln dried you should be getting a relatively dry material .forget what the moisture specs are so reluctant to give numbers

View jbay's profile

jbay

2748 posts in 1073 days


#9 posted 05-20-2017 10:18 PM

Because they pay less for it.

-- “Hanging onto resentment, is letting someone you despise live rent-free in your head.” (Ann Landers)......

View JohnnyBoy1981's profile

JohnnyBoy1981

235 posts in 611 days


#10 posted 05-20-2017 11:44 PM

I ran into this problem too. I bought some 2×4x8 studs that were advertised as kiln dried from Lowe’s. I was digging through a large pallet of them, but the deeper into the pile I got the more I noticed that the boards were fairly damp. I grabbed the straightest boards I could find and laid them out in my garage about a week ago. I haven’t checked them to see if they’ve dried into a horseshoe shape.

View Carloz's profile

Carloz

1147 posts in 765 days


#11 posted 05-20-2017 11:51 PM

My guess is that they pass the risk of the wood twisting and bending to the customer. While it is wet is stays straight. When it dries it looses the shape and then nobody want to buy it in the store.

View Hermit's profile

Hermit

209 posts in 1499 days


#12 posted 05-21-2017 05:05 PM

Lumber mills here will put sprinklers on top to keep the logs wet for a number of reasons. Reduce the risk of fire, easier to cut wet wood, easier on their saw blades, keep powder post beetles out etc. If you were to buy 2×4’s that were dried and unbanded I doubt you’d find a straight one.

-- I'm like the farmer's duck. If it don't rain, I'll walk.

View tomsteve's profile

tomsteve

844 posts in 1393 days


#13 posted 05-21-2017 11:53 PM

when framing lumber is put into a kiln, there are no stickers between each layer- it is put in the kiln just as it is found at the store. the lumber on the ouside of the stack may be down to 18% mc, but the lumber in the middle isnt.
the only way to tell the MC is by using a moisture meter. cut a pice off and put the pins in the cut end. using the weight of a piece of lumber as a measurement of moisture content is not accurate at all.

View bruc101's profile

bruc101

1255 posts in 3716 days


#14 posted 05-22-2017 03:10 AM

Our HD sells only KD Spruce and SYP. In the past year they’ve also started selling Fir that seems to be wet and heavy and I don’t mess with it.

Just this past week I bought a Spruce 2×6 12 feet long from our HD to match a table leg, I glued it up to make a 4 inch leg and turned it yesterday. It was very dry and turned beautifully for such a soft wood. It sanded out smooth except in a couple of places and a small amount of speckling paste fixed that.

The 2×4’s are no different than the 2×6’s and I’ve never had any problems with them.

-- Bruce Free Plans http://plans.sawmillvalley.org

View Carloz's profile

Carloz

1147 posts in 765 days


#15 posted 05-22-2017 02:57 PM

the only way to tell the MC is by using a moisture meter. cut a pice off and put the pins in the cut end. using the weight of a piece of lumber as a measurement of moisture content is not accurate at all.

- tomsteve


Is it ? Moisture meters is nothing more than an ohmmeter that tries to guess the moisture content based on the resistance. It cannot be very accurate as there are many factors involved, such as how clean and free of oxidation the probes are. how good contact with the wood is and most importantly how uniformly dry the wood is. Green wood moisture content at the surface is very different from that of in the center. You suggest to cut off the piece and measure it, however the moisture at the end of a board again is different from the moisture at the middle of the board ( that is why lumber cracks at the edges more when drying). Also I would guess the resistance of the same wood could be very different depending on the soil where the tree grows. The more salt is in the soil the lower is the wood electric resistance.
Measuring by the weight change if far more accurate. Wood consists of dry matter with density approximately the same across the same wood species and water. If you know the wood density ( most wood databases will give you that number ) calculating accurate moisture content is a straightforward task.

View Hermit's profile

Hermit

209 posts in 1499 days


#16 posted 05-22-2017 11:50 PM

Buying a better quality moisture meter will help. I use http://www.inspectortools.com/Tramex-Moisture-Encounter-Plus-Moisture-Meter-p/tr115.htm
I’ve had this one for probably 15 years. Pentetrates 1” deep.
The inexpensive pin type aren’t very accurate.

-- I'm like the farmer's duck. If it don't rain, I'll walk.

View diverlloyd's profile

diverlloyd

3179 posts in 2031 days


#17 posted 05-23-2017 03:05 AM

Get a good moisture meter and let the wood sit for a couple months to equalize. Carloz you could make the same arguement about wood density not being the same due to no two trees being the same or if it’s heart wood or sap wood or a burl in a piece or a knot. Do you know the exact species of wood the 2×4 is made of? That will all change your calculations and what scale are you using to weight said wood is it calabrated. Oddly enough I just walked out to the shop and measured the moisture content with a good meter and a $8 dollar meter both are within 1% of each other and the nice one just got back from being calabrated. 2×6 is only a 2% difference from the pre cut ends to the center cut I made 9% on the ends and 11% on the center with the good meter the cheap one is reading 10% and 11%and on pressure treated I only did the ends I’m not cutting the crap but it’s reading 18% on both meters stuffs nasty anyways. All the wood was purchased this afternoon and dropped off a couple hours ago.
If anyone is interested in how the math works for carloz’s way
https://is.mendelu.cz/eknihovna/opory/zobraz_cast.pl?cast=19370.
I think I will stick with the meter it will be close enough for the unsavory types I run with.

To answer your original question it’s because big box stores don’t care about it the same way that a 2×4 or 3/4 ply is that size when they are not 90% of their customers don’t care so neither do they. Local sawmill kiln dried wood is what the say it is if it’s a 2×6 then that what it is not 1 1/2×5 1/2.

View bondogaposis's profile

bondogaposis

5053 posts in 2525 days


#18 posted 05-23-2017 12:41 PM

Construction lumber is not dried to the level that furniture lumber is. 18 -20% is pretty standard for 2×4’s fresh from the mill.

-- Bondo Gaposis

View Tennessee's profile

Tennessee

2887 posts in 2688 days


#19 posted 05-23-2017 12:46 PM

I think the problem is simpler than most think.
HD buys in bulk, from various sources, taking into consideration cost of the lumber and shipping costs.

So it is not out of the question that a load of lumber destined for a store in Arizona might have come from a mill a couple of states away.
All of the lumber that I have ever seen being unloaded at any big box store has arrived on flat bed truck. (Correct me if I am wrong.)
This means that your driver could have driven through a major rain storm, sat overnight in a truck stop in a pouring rain, etc. And although it should have been wrapped or at least a tarp, it is also likely that water easily penetrated the stack while underway, or sitting overnight.

My experience with HD and Lowe’s is you just don’t know what you will find from day to day in their stacks. Some days nice, straight, fairly dry, some days full of knots, lots of warp, wet, etc. It’s the lowest form of lumber buying save for pallet wood.

-- Tsunami Guitars and Custom Woodworking, Cleveland, TN

View Tennessee's profile

Tennessee

2887 posts in 2688 days


#20 posted 05-23-2017 12:48 PM

And most decent home builders won’t even buy their lumber from places like HD. They go to known sources with dry, straight lumber since they don’t need the headaches on framing out their structures.

-- Tsunami Guitars and Custom Woodworking, Cleveland, TN

View gargey's profile

gargey

1013 posts in 949 days


#21 posted 05-23-2017 01:48 PM

Doug Fir weighs a shit ton more than Hemlock, so weight isn’t a great indicator of moisture content unless you’re quite familiar with what you’re doing.

View tomsteve's profile

tomsteve

844 posts in 1393 days


#22 posted 05-25-2017 11:20 PM



Doug Fir weighs a shit ton more than Hemlock, so weight isn t a great indicator of moisture content unless you re quite familiar with what you re doing.

- gargey

not only that, 2 pieces of the same species of wood, same volume, can have 2 different weights even when they have the identical moisture content.

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