Does pressure treated lumber shrink? It’s a common question, and the answer is yes, it does. In fact, the treatment process itself causes the wood to swell with moisture, often reaching up to 50% moisture content. When exposed to air, the treated lumber will shrink, a process that takes months. This shrinkage can lead to paint cracking and poor adhesion, especially on installed decks and boards.
When installed, the treated lumber will dry at different rates, its width fluctuating as it absorbs and releases moisture. With proper sealing, however, these fluctuations can be minimized, allowing you to enjoy your deck without worrying about the shrinkage rates.
What’s the Best Way to Seal Pressure-treated Wood Surfaces to Prevent Further Shrinkage and Cracking?
When it comes to sealing pressure-treated wood surfaces, prevention is key. To prevent further shrinkage and cracking, follow these simple steps:
- Clean the surface thoroughly with a wire brush and soap to remove dirt, grime, and any old sealants.
- Use a wood filler to fill any cracks or holes.
- Apply a coat of primer specifically designed for use on pressure-treated wood.
- Use a high-quality, water-based or oil-based sealant, depending on your preference and the type of wood.
- Apply the sealant evenly, following the manufacturer’s instructions.
- Allow the sealant to dry according to the manufacturer’s instructions.
- Repeat the process as needed, typically every 2-5 years, depending on the environment and usage.
Remember to choose a sealant that’s compatible with the type of pressure-treated wood you’re working with. Some popular options include:
- TWP 1500 Wood Sealer
- Thompson’s WaterSeal
Keep in mind that it’s essential to follow the manufacturer’s instructions for each product, as well as any local regulations or restrictions.
How Do Moisture Rates Influence the Shrinkage of Treated Lumber during Installation?
When installing treated lumber, it’s essential to consider the moisture rate to ensure a successful and durable outcome. Moisture rates play a significant role in the shrinkage of treated lumber during installation.
Factors Affecting Moisture Rates
Moisture rates are influenced by several factors, including:
- Climate and region : Different regions have varying levels of humidity, temperature, and precipitation, which affect the moisture content of the lumber.
- Lumber grade and type : The type and grade of lumber can affect its moisture content and absorption rate.
- Environmental conditions : Lumber exposed to direct sunlight, high temperatures, or high humidity will experience more shrinkage than lumber in a shaded, cooler, or drier environment.
How Moisture Rates Influence Shrinkage
As treated lumber is exposed to its new environment, it will adjust to the surrounding moisture levels. If the moisture rate is:
- Higher than the lumber’s natural moisture content , the lumber will absorb more moisture and expand. This can cause fitting issues, such as gaps between boards, and may lead to increased risk of rot and pest infestation.
- Lower than the lumber’s natural moisture content , the lumber will release moisture and shrink. This can cause gaps between boards, and may lead to increased risk of warping and cracking.
Recommendations for Successful Installation
To minimize the impact of moisture rates on treated lumber shrinkage:
- Choose the right lumber grade and type for your specific climate and environmental conditions.
- Monitor and control environmental conditions during installation to minimize exposure to extreme temperatures, humidity, and sunlight.
- Follow manufacturer recommendations for installing and maintaining the treated lumber to ensure optimal performance and durability.
Understanding the relationship between moisture rates and shrinkage is crucial for a successful treated lumber installation. By considering these factors and taking proactive measures, you can ensure a durable and long-lasting outcome.
What’s the Average Cost of Pressure-treated Lumber to Consider for a Deck Installation?
If you’re planning to build a deck, one of the essential components to consider is pressure-treated lumber. This type of lumber provides protection against rot, decay, and termite damage, ensuring your deck remains sturdy and safe for years to come.
- Types of Pressure-Treated Lumber:
- Ground-contact lumber: Designed for use with footings, piers, and other underground applications
- Above-ground lumber: Suitable for use in decks, fences, and other above-ground structures
- Factors Affecting Cost:
- Lumber grade: Higher grades like #1 and #2 are more expensive than lower grades like #3 and #4
- Lumber width: Wider boards are more expensive than narrower ones
- Quantity: The more lumber needed, the higher the cost
- Regional pricing: Prices vary depending on your location and the supplier you choose
So, what’s the average cost of pressure-treated lumber for a deck installation? Here are some general estimates:
- Ground-contact lumber: $0.50 to $1.00 per linear foot for a 2×6 beam
- Above-ground lumber: $0.30 to $0.60 per square foot for a 2×6 deck board
- Decking accessories (screws, nails, etc.): $0.10 to $0.30 per piece
Keep in mind that these estimates are rough and may vary depending on the specific needs of your project. It’s always a good idea to consult with a professional contractor or supplier to get a more accurate quote. They can help you determine the best type and amount of pressure-treated lumber needed for your deck installation.
Can You Perform a Simple Test to Check If Your Pressure-treated Lumber is Already Shrunken?
If you’re dealing with pressure-treated lumber that’s been stored for a while, it’s essential to inspect it before using it for your project. One simple test can help you determine if the lumber has already shrunk.
The Test
To perform the test, follow these steps:
- Find a straight section of the lumber with no knots or branches.
- Measure the width of the lumber using a tape measure or calipers.
- Submerge the lumber in a bucket of water for at least 30 minutes. This will help the lumber relax and return to its original state.
- Remove the lumber from the water and measure the width again . Compare the two measurements.
If the lumber has shrunken, the second measurement will be smaller than the first. The difference in measurements can give you an idea of the shrinkage rate.
What to Look For
When inspecting the lumber, pay attention to any cracks, warping, or twisting. These signs can indicate that the lumber is already shrunken or prone to shrinkage.
Keep in mind that not all pressure-treated lumber will shrink equally. The type and quality of treatment, as well as the drying process, can affect the lumber’s final dimensions.
Can You Still Use Treated Wood for Decking If It’s Been Left Outside for a While?
If you’ve had treated wood for decking sitting outside for a bit, you’re probably wondering if it’s still good to use. The answer lies in the type of treatment and how well the wood has been maintained.
- Borate-treated wood: If the wood was treated with borate, it’s likely still effective against insects and rot. However, the treatment may start to break down over time, making it less effective.
- Alkaline copper quaternary (ACQ)-treated wood: ACQ-treated wood is more susceptible to decay if left outside for too long. The copper components can leach out, reducing the wood’s protection against rot and insects.
- Copper azole (CA)-treated wood: CA-treated wood is known for its long-lasting protection against rot and insects. Even if left outside for a while, the treatment should still be effective.
Before using treated wood for decking, inspect it for signs of damage or decay. Look for cracks, splits, or discoloration, and check for any visible rot or insect infestation. If the wood looks good, you can still use it, but you may want to apply a deck sealant or stain to protect it further.
What Happens to the Width of Pressure-treated Boards as They Dry Entirely?
Pressure-treated boards are a popular choice for outdoor projects, such as decking, fencing, and patio construction. However, as they dry completely, the width of these boards can change. Here’s what you need to know:
How Pressure-Treating Works
Pressure-treating involves immersing cedar or pine lumber in a chemical solution, typically containing copper or arsenic, to resist rot and insect damage. The treatment process involves forcing the chemical solution into the wood under pressure, which helps it penetrate deeper into the wood fiber.
Impact on Wood Grain
When the wood grain shrinks due to drying, the width of pressure-treated boards can change. Here are a few key factors to consider:
- Wood grain direction : Wood grain direction affects the rate of shrinkage. For example, wood with a strong directional grain, like eastern white pine, tends to shrink more than wood with a less directional grain, like Douglas fir.
- Moisture content : The moisture content of the wood also plays a role. Wood with higher moisture content will shrink more than wood with lower moisture content.
- Pressure-treating process : The pressure-treating process itself can influence the wood grain’s direction and subsequent shrinkage.
What to Expect
As pressure-treated boards dry completely, you can expect the following changes:
- Width reduction : The width of the boards will likely decrease due to the shrinkage of the wood grain.
- Length and thickness changes : The length and thickness of the boards may also change, although not as significantly as the width.
- Neighborly effects : The drying process can also cause neighboring boards to shift or separate, potentially affecting their alignment and stability.
Wrapping Up
When it comes to pressure-treated boards, it’s essential to consider the impact of drying on their width and structure. By understanding how the grain direction, moisture content, and pressure-treating process influence shrinkage, you can better plan and execute your outdoor projects. Remember to monitor your boards’ dimensions and adjust accordingly to ensure a sturdy and visually appealing final product.
