ByJack Gray, Roof Online Editor• Last updated September 26, 2022
Table of Contents
- Introduction: Pressure Treated Lumber Weight Factors
- About These Pressure Treated Lumber Weight Values
- Table: Pressure Treated Lumber Weight by Board Size
- Type of Wood Used for Pressure-Treating
- Wood Pressure-Treatment Process
- Weight of Water in Pressure-Treated Wood
- Weight of Preservative in Pressure Treated Lumber
- Ask the Lumber Company!
- Related Pages
- More Resources for Information on Pressure-Treated Wood
Introduction: Pressure Treated Lumber Weight Factors
The weight of pressure treated lumber depends on how much time has gone by since the wood was treated, as well as the size of the board or post.
Most pressure treated lumber is made from southern yellow pine, which is a relatively heavy wood to begin with, so pressure-treated wooddoestend to be heavier than most other lumber because of this alone.
But the weight that people really notice when it comes to treated lumber is the water weight that the wood picks up while being treated.
A 6×6×10-foot long treated post weighs about 153 pounds immediately after being pressure-treated, but it will only weigh around 87 pounds after it has had time to dry out.
And a 10-foot-long 2×6 pressure treated board will weigh around 40 pounds right after being treated. The same board will only weigh around 23 pounds after it has had time to dry out.
About These Pressure Treated Lumber Weight Values
The following table provides the heaviest approximate weight (dead load, self-weight)per linear footof pressure treated lumber.
The weight values we provide are for the wood immediately after being treated, for the wood after it has dried thoroughly, and for untreated wood with the same dimensions.
The values given are for one of the densest wood species, longleaf pine (southern yellow pine, longleaf), commonly used to produce pressure treated lumber.
This table is intended to give you an idea as to what pressure-treated wood might weigh at its heaviest.
The “freshly treated” column in the chart shows the weight for the wood when it contains the highest amount of water commonly added to the wood during treatment (close to four gallons, or about 32 lbs., per cubic foot).
Table: Pressure Treated Lumber Weight by Board Size
For an explanation of the difference betweennominallumber dimensions andactualdimensions, see ourLumber Dimensions Table.
| Weight of Pressure Treated Lumber | ||||
|---|---|---|---|---|
| (Made from the Longleaf Pine Species of Southern Yellow Pine) | ||||
| Nominal Dimensions of Lumber in Inches | Actual Dimensions of Lumber in Inches | Untreated Lumber Weight (Air Dried Lumber) | Freshly Treated Lumber Weight (Maximum Weight) | Treated Lumber Weight After Drying |
| Cubic Foot | 12 x 12 x 12 | 41 pounds per Cubic Foot | 73 pounds per Cubic Foot | 41.6 pounds per Cubic Foot |
| Board Foot | 12 x 12 x 1 | 3.42 pounds per Board Foot | 6.08 pounds per Board Foot | 3.47 pounds per Board Foot |
| Per Linear Foot: | Per Linear Foot: | Per Linear Foot: | ||
| 1 inch x 2 inch | 0.75 inch x 1.5 inch | 0.32 lb | 0.57 lb | 0.32 lb |
| 1 x 3 | 0.75 x 2.5 | 0.53 lb | 0.94 lb | 0.54 lb |
| 1 x 4 | 0.75 x 3.5 | 0.75 lb | 1.34 lb | 0.76 lb |
| 1 x 6 | 0.75 x 5.5 | 1.17 lb | 2.08 lb | 1.18 lb |
| 1 x 8 | 0.75 x 7.25 | 1.61 lb | 2.87 lb | 1.63 lb |
| 1 x 10 | 0.75 x 9.25 | 1.98 lb | 3.52 lb | 2.00 lb |
| 1 x 12 | 0.75 x 11.25 | 2.40 lb | 4.27 lb | 2.42 lb |
| 5/4 x 6 | 1 x 5.5 | 1.57 lb | 2.79 lb | 1.59 lb |
| 5/4 x 8 | 1 x 7.25 | 2.06 lb | 3.67 lb | 2.09 lb |
| 2 x 2 | 1.5 x 1.5 | 0.64 lb | 1.14 lb | 0.65 |
| 2 inch x 3 inch | 1.5 inch x 2.5 inch | 1.07 lb | 1.90 lb | 1.08 lb |
| 2 x 4 | 1.5 x 3.5 | 1.49 lb | 2.65 lb | 1.5 lb |
| 2 x 6 | 1.5 x 5.5 | 2.34 lb | 4.17 lb | 2.36 lb |
| 2 x 8 | 1.5 x 7.25 | 3.09 lb | 5.50 lb | 3.12 lb |
| 2 x 10 | 1.5 x 9.25 | 3.95 lb | 7.03 lb | 3.99 lb |
| 2 x 12 | 1.5 x 11.25 | 4.80 lb | 8.54 lb | 4.85 lb |
| 2 x 14 | 1.5 x 13.25 | 5.65 lb | 10.06 lb | 5.71 lb |
| 2 x 16 | 1.5 x 15.25 | 6.52 lb | 11.61 lb | 6.58 lb |
| 3 x 4 | 2.5 x 3.5 | 2.49 lb | 4.43 lb | 2.51 lb |
| 3 x 6 | 2.5 x 5.5 | 3.91 lb | 6.96 lb | 3.95 lb |
| 3 inch x 8 inch | 2.5 inch x 7.25 inch | 5.15 lb | 9.17 lb | 5.20 lb |
| 3 x 10 | 2.5 x 9.25 | 6.59 lb | 11.73 lb | 6.65 lb |
| 3 x 12 | 2.5 x 11.25 | 8.01 lb | 14.26 lb | 8.09 lb |
| 3 x 14 | 2.5 x 13.25 | 9.43 lb | 16.79 lb | 9.52 lb |
| 3 x 16 | 2.5 x 15.25 | 10.85 lb | 19.31 lb | 10.96 lb |
| 4 x 4 | 3.5 x 3.5 | 3.49 lb | 6.21 lb | 3.52 lb |
| 4 x 6 | 3.5 x 5.5 | 5.48 lb | 9.75 lb | 5.53 lb |
| 4 x 8 | 3.5 x 7.25 | 7.22 lb | 12.85 lb | 7.29 lb |
| 4 x 10 | 3.5 x 9.25 | 9.23 lb | 16.43 lb | 9.32 lb |
| 4 x 12 | 3.5 x 11.25 | 11.22 lb | 19.97 lb | 11.33 lb |
| 4 inch x 14 inch | 3.5 inch x 13.25 inch | 13.21 lb | 23.51 lb | 13.34 lb |
| 4 x 16 | 3.5 x 15.25 | 15.2 lb | 27.06 lb | 15.35 lb |
| 6 x 6 | 5.5 x 5.5 | 8.61 lb | 15.33 lb | 8.69 lb |
| 6 x 8 | 5.5 x 7.25 | 11.35 lb | 20.20 lb | 11.46 lb |
| 6 x 10 | 5.5 x 9.25 | 14.48 lb | 25.77 lb | 14.62 lb |
| 6 x 12 | 5.5 x 11.25 | 17.62 lb | 31.36 lb | 17.79 lb |
| 6 x 14 | 5.5 x 13.25 | 20.75 lb | 36.94 lb | 20.95 lb |
| 6 x 16 | 5.5 x 15 | 23.49 lb | 41.81 lb | 23.72 lb |
| 8 x 8 | 7.25 x 7.25 | 14.97 lb | 26.65 lb | 15.12 lb |
| 8 x 10 | 7.25 x 9.25 | 19.09 lb | 33.98 lb | 19.28 lb |
| 8 inch x 12 inch | 7.25 inch x 11.25 inch | 23.22 lb | 41.33 lb | 23.45 lb |
| 8 x 14 | 7.25 x 13.25 | 27.35 lb | 48.68 lb | 27.62 lb |
| 8 x 16 | 7.25 x 15 | 30.97 lb | 55.13 lb | 31.27 lb |
| 8 x 18 | 7.25 x 17 | 35.10 lb | 62.48 lb | 35.44 lb |
| 10 x 10 | 9.25 x 9.25 | 24.37 lb | 43.38 lb | 24.61 lb |
| 10 x 12 | 9.25 x 11.25 | 29.62 lb | 52.72 lb | 29.91 lb |
| 10 x 14 | 9.25 x 13.25 | 34.89 lb | 62.10 lb | 35.23 lb |
| 10 x 16 | 9.25 x 15 | 39.51 lb | 70.33 lb | 39.90 lb |
| 10 x 18 | 9.25 x 17 | 44.78 lb | 79.71 lb | 45.22 lb |
| 12 x 12 | 11.25 x 11.25 | 36.04 lb | 64.15 lb | 36.39 lb |
| 12 inch x 14 inch | 11.25 inch x 13.25 inch | 42.44 lb | 75.54 lb | 42.86 lb |
| 12 x 16 | 11.25 x 15 | 48.04 lb | 85.51 lb | 48.51 lb |
Type of Wood Used for Pressure-Treating
Around 85% of the pressure-treated wood in the US is made from southern yellow pine.
There are a few different sub-species of southern yellow pine, with different wood densities. We used the longleaf variety to calculate the values shown in the chart.
SeeWeight of Dimensional Lumberfor the weights of other wood species commonly used for lumber.
A much more extensive list of wood densities, which includes the other varieties of southern yellow pine, can be found in “Weights of Various Woods Grown in the United States“.
Wood Pressure-Treatment Process
Pressure treated lumber is produced by usinghigh pressure to force a solution of water and chemical preservatives deep into the wood.
Stacks of lumber are placed in a large steel cylinder in a bath of water and preservative. This tank is pressurized until the wood becomes saturated.
After the wood dries out, the preservative remains throughout the wood, protecting it from decay for years.
Weight of Water in Pressure-Treated Wood
The noticeable extra weight of pressure treated lumber is due to the water added during the treatment process.
Typically, close to four gallons of water (almost 32 pounds) of water is added to each cubic foot of pressure-treated wood. This means that the wood weighs over 75% more when it comes out of the tank than when it goes in.
As the wood returns to its normal air dried weight over the following weeks or months, it also returns (almost) to its pre-treated weight.
Weight of Preservative in Pressure Treated Lumber
Once it dries, the weight difference between pressure treated lumber and untreated lumber is entirely due to the weight of the preservative retained in the wood. This weight is minimal.
The maximum additional weight due to preservative is around 1.5% for “ground contact” designated lumber using CCA (chromated copper arsenate) or ACQ (alkaline copper quaternary) as a preservative.
For much of the pressure treated lumber available today for residential use, the additional weight will be less. “Ground contact” lumber treated with the widely-used CA-C (copper azole, type C), for instance, will only weigh about 0.37% more than untreated wood.
Ask the Lumber Company!
The values given in the table are meant to provide a general idea of typical pressure treated lumber weights, and should not be used if precise values are needed for critical engineering calculations.
When precision is necessary, always refer to the specification sheet for the actual, specific product you intend to use, or contact the technical department of the lumber producer.
Seepressure treated lumber at the Home Depot. The approximate weights of the actual pieces of pressure treated lumber for sale are usually given in the product descriptions, so this can be a good resource for calculating these weights. Home Depot also delivers to your home, by the way.
About the Author
Jack Gray is a principal roof consultant and vice president at theMoriarty Corporation, an award-winning building enclosure consultant firm founded in 1967. He is also the editor of the Roof Online website.
Mr. Gray has worked in the roofing industry for over 25 years, with training and practical experience in roof installation, roof inspection, roof safety, roof condition assessment, construction estimating, roof design & specification, quality assurance, roof maintenance & repair, and roof asset management.
He was awarded the Registered Roof Observer (RRO) professional credential in 2009.
He also served as an infantry paratrooper in the 82nd Airborne Division and has a B.A. from Cornell University. Read full bio.
Related Pages
- Weight of a 2×4 by Wood Type and Length
- Weight of a 2×6 by Wood Type and Length
- Weight of a 2×8 by Wood Type and Length
- Weight of a 2×10 by Wood Type and Length
- Weight of a 4×4 by Wood Type and Length
- Weight of a 6×6 by Wood Type and Length
- Weight of Dimensional Lumber
- Weight of Plywood and OSB
- Weight of Roofing Materials
More Resources for Information on Pressure-Treated Wood
- Guidelines for Selection and Use of Pressure-Treated Wood – Forest Products Laboratory, US Forest Service, USDA
- PreservedWood.org, the website of the the Western Wood Preservers Institute (WWPI)
