How do I keep my deck boards from shrinking?
If you have a high moisture content, leave less space between the boards as they will shrink as the moisture is released. If you have a low moisture content, leave more space to accommodate the expansion of the boards as they gain more moisture.
Do pressure treated deck boards shrink?
Treated wood is often still damp when delivered, so it is recommended to butt deck boards tightly together during installation as they will shrink slightly in width and length as they dry out.
How much do decking boards shrink?
Wood doesn't expand or contract equally in all directions. For example, a 16-ft pine board could potentially shrink around 1/8 to 3/16” in length, and ¼" in width as it dries.
Does decking timber shrink?
Note: Decking shrinks and expands by varying amounts depending on the species. Laying kiln dried decking boards tight (ie with no gap) will not allow water to be shed from the deck.. If decking is green or wet after treatment then this is not such an issue as the deck will shrink as it dries out.
How do you prevent wood shrinkage?
Keep your house at 40 percent humidity (not lower than 35 percent) if you have lots of wood in your house. Keeping your humidity (moisture in the air) at this level really helps with shrinkage since the wood will acclimate to that moisture level. When the humidity is high, it's the exterior air that's humid.
Do deck boards swell or shrink?
It's also critical to remember that wood is a natural material that slightly expands and contracts depending on the humidity and moisture levels in the environment in which the deck is installed. As a result, you need to ensure you leave the proper spacing between boards when you install your wood decking.
How long does it take deck boards to shrink?
Over time, most treated lumber will shrink slightly across its width as it dries out. Take this small amount of shrinkage into account when laying decking or fence boards. After being outdoors for six to 12 months, treated lumber will develop cracks, called "checks," along the surface of each board.
How much does pressure treated boards shrink?
In the area you plan to use the PT, look for a similar material that's been installed. For 1x12 you might look at and measure several wooden fences and measure the gap. Most installers butt the pickets tight and level as they go. Most 1x6 pickets here shrink a little less than 1/2" or about 9%.
Do treated boards shrink?
After all, this is a naturally made material that swells when wet and dries in the sun. Even products that are sealed and treated are going to shrink. This most typically occurs across the width of boards, so builders should take into consideration the fact that their lumber will shrink over time.
What is the average lifespan of decking?
Life Expectancy
Softwood decking will typically last between 10 to 15 years and will need to be regularly treated. Well-maintained hardwood decking can last for longer and, in some cases, can last for as long as 25 years. Regularly oiling, cleaning, and refinishing will be needed.
Do you need a gap between deck boards?
Traditional wood decking is typically installed with a 1/8” gap, as long as you install the boards after they have dried out and acclimated to your local climate. If installing freshly treated wood, install it tight (no gap) to allow for the shrinkage.
Do you need to leave a gap between pressure treated deck boards?
How much room should you leave between treated lumber boards? If you're building with kiln-dried lumber, make sure to leave boards ⅛'' apart for the best results. You can use a framing nail or a 16D nail to make sure that each board is a uniform distance from each other.
What causes shrinkage in timber?
Shrinking and swelling occur as the wood changes moisture content in response to daily as well as seasonal changes in the relative humidity of the atmosphere, i.e., when the air is humid, wood adsorbs moisture and swells; when the air is dry, wood loses moisture and shrinks.
Does wood shrink more in length or width?
Wood is fairly stable along its longitudinal direction, parallel to the grain. Green lumber shrinks only 0.01 percent of its length as it dries. An 8-foot-long board will move only 3/32 inch. Wood moves much more across the grain, tangent to the growth rings.
Does decking expand in summer?
Decking expands in the heat and contracts in the cold; therefore, when installing, close attention must be paid to the weather conditions during the installation. All boards will expand when exposed to high temperatures.
Does cold make wood shrink?
Generally speaking, wood does tend to contract in cold temperatures. This is because the molecules within the wood slow down and move closer together, causing the wood to shrink. Conversely, in warmer temperatures, the molecules speed up and move further apart, causing the wood to expand.
What is it called when wood shrinks?
The amount a piece of wood will shrink lengthwise, called longitudinal shrinkage, is so small—typically about 0.1% to 0.2%—that it is usually inconsequential to the volumetric shrinkage.
How much do boards shrink when drying?
This is called the tangential surface. Wood shrinks about 8 percent along this surface as it dries from fsp to 0 percent MC. Thus, a 10" wide quartersawn board dried from fsp (assume 30 percent MC) to 15 percent MC would shrink about 0.4" in width.
Why are my deck boards cupping?
The combination of 'too moist' conditions on the bottom of the deck board and too dry on the top, creates internal stresses in the wood. The wood will cup upwards naturally to relieve the internal stress.
Does pressure treated wood shrink or swell?
While the chemicals in pressure treated lumber prevent rot and ward off insects, they don't prevent moisture from seeping into the wood. On a deck that's going to be directly exposed to rain, water can seep into the boards and cause them to swell. As they dry in the sun, they'll shrink.
How do you tighten deck boards?
It's best to install wood deck boards in dry, warm weather. If installing in rainy or humid weather, make sure to minimize the space between the deck boards because they will contract over time.
Should deck boards be wet or dry when installing?
One to two weeks is usually sufficient, as long as your wood is stored properly during this period. DON'T: Never install your wood decking or siding immediately. If your outdoor wood acclimates too quickly, you may get excessive surface checking, cupping, twisting, warping or other problems.
Should I let deck boards dry before installing?
For example, if you don't give the wood enough time to dry after pressure treatment, you risk a patchy, uneven paint job. Here's the scoop on how to properly stain pressure-treated wood for the best end product, whatever your project may be.
What happens if you stain pressure treated wood too soon?
If you put deck boards in wet you are supposed to put them on pushed completely t and then they will shrink about 1/4" in width. However when the shrink they tend to split along the grain where the screws are because the screws won't let the board shrink so it splits instead.
How do you keep pressure treated boards from warping?
Clean, Dry Storage
Keeping a clean and dry storage area for your wood can prevent moisture from causing it to warp. Here are a few ways to ensure that you store your wood properly: Put wood piles onto flat foundations. Place wood boards and the stickers in uniform stacks with boards of the same thickness.
Can you lay wet decking boards?
The wood will expand pretty much the same thing that happens when untreated wood gets wet. Therefore, when building with treated lumber, you must allow for its expansion should it get wet. The growth of wood when it gets wet, any competent carpenter or woodworker will consider the change of the wood.
How do you keep pressure treated lumber from warping?
Pressure treatment with waterborne preservatives leaves some moisture in the wood that may affect the penetration and drying of stains and paints. For optimal performance of paint and stain coatings, allow the treated wood to dry prior to application.
Does treated wood expand when wet?
Adequate spacing between boards provides for possible expansion and also caters for ventilation: · Decking boards up to 90mm wide must have a minimum of 5mm gap between board edges. Decking boards wider than 90mm must have a minimum of 8mm gap between board edges.
Should you let pressure-treated wood dry?
If you're going to install a new one, or you moved into a house that already has a deck, you're likely wondering when you'll need to consider replacing it. You can typically expect a deck to last 10-30 years for untreated wood and 50 or more years for treated wood and composite.
What is the standard gap between decking boards?
This is an easy DIY project that doesn't require a permit or, in most cases, rebuilding the deck's structure, because posts and joists aren't directly exposed to the elements and often outlast the decking. You'll save a lot of time and money by replacing only the worst deck boards instead of the whole deck.
Can a wood deck last 30 years?
Significant, Noticeable Damage
From cracks to missing screws, some deck issues will lead to a simple repair while other damage will require a full replacement. If you notice significant damage, such as large holes, split boards, signs of termites, and many other issues, you know you need a new deck.
Can I just replace deck boards?
Wood doesn't expand or contract equally in all directions. For example, a 16-ft pine board could potentially shrink around 1/8 to 3/16” in length, and ¼" in width as it dries. Different wood species have different coefficients of shrinkage as they dry. The importance of deck board spacing can't be overemphasized.
How do you know if your deck needs replacing?
Regular pressure treated wood tends to be somewhat wet when it's new. That means, as it weathers in the sun and the heat, it will dry out some and shrink slightly.
How much do deck boards shrink?
For deck boards, screws are the fasteners you want to use for holding strength. They provide excellent retention of the boards and prevent the dreaded board squeak that occurs when nails are used. Board squeak is what happens when there is distance between the deck board and the frame.
Does pressure treated wood shrink?
How much will decking boards shrink and how should I install them? Treated wood is often still damp when delivered, so it is recommended to butt deck boards tightly together during installation as they will shrink slightly in width and length as they dry out.
Should you nail or screw deck boards?
Are the boards on your patio deck too close together? If so, they may cause deck rot. When the deck boards are too close together, water won't drain properly and air does not circulate. Your deck boards stay wet causing rot and that can lead to structural failure/ wood rot.
Will deck boards shrink?
Without the right deck spacing, the boards may expand, cup, and buckle out of place. As a result, you may have to replace broken decking, or reinstall the boards with wider spacing to prevent further cupping and buckling, which can be time consuming and expensive.
What happens if deck boards are too close together?
Keep your house at 40 percent humidity (not lower than 35 percent) if you have lots of wood in your house. Keeping your humidity (moisture in the air) at this level really helps with shrinkage since the wood will acclimate to that moisture level. When the humidity is high, it's the exterior air that's humid.
What happens if you don't space deck boards?
There are four main causes of shrinkage: shoplifting, employee theft, administrative errors, and fraud. Understanding how shrinkage happens in retail stores is the first step in reducing and preventing it.
How do you stop wood from shrinking?
Rather, wood expands and contracts with changes in the atmospheric humidity. In Understanding Wood, Bruce Hoadley estimates that the seasonal change in humidity in the average U.S. climate for a two-story wood-framed house can change the height of a house by 3/4”!
What is the biggest cause of shrinkage?
This is because much of its water content is removed during tree cutting. Then, it will continue to shrink gradually during the drying stage. This may take several years, depending on the type of wood, how it was cut, the weather and humidity in the area where it will be dried.
What are the four major causes of shrinkage?
As noted in Chapter 4 of the USDA Forest Products Lab's Wood Handbook, “The thermal expansion coefficients of completely dry wood are positive in all directions; that is, wood expands on heating and contracts on cooling.” However, moisture fluctuations impact dimensional movement of the wood at the same time.
Does wood shrink in summer?
As temperatures change, deck boards expand and contract - without the right gapping, your boards can warp, buckle, or leave big, unsightly gaps in your deck surface. In addition, leaving the right gaps between your deck boards allows water to drain away rather than gathering on your deck surface.
How long does it take for lumber to shrink?
Life Expectancy
Softwood decking will typically last between 10 to 15 years and will need to be regularly treated. Well-maintained hardwood decking can last for longer and, in some cases, can last for as long as 25 years. Regularly oiling, cleaning, and refinishing will be needed.
Does wood shrink in heat or cold?
When humidity is high, wood absorbs moisture and swells. When humidity drops, wood shrinks. This “movement” is gradual, so you probably won't notice weekly changes. But seasonal changes cause problems you can't miss, like sticking doors, ugly gaps in woodwork or a crack in a tabletop.
Do deck boards shrink or expand?
Wood shrinks to its smallest dimension in the winter and swells to its maximum in the summer. The wood in winter projects will expand; the wood in summer projects will contract. In the spring and fall, remember that the wood will expand half your total movement allowance and contract the other half.
What is the average lifespan of decking?
The greatest shrinkage occurs parallel to the growth rings. This is called the tangential surface. Wood shrinks about 8 percent along this surface as it dries from fsp to 0 percent MC. Thus, a 10" wide quartersawn board dried from fsp (assume 30 percent MC) to 15 percent MC would shrink about 0.4" in width.
What causes wood to shrink?
This shrinkage varies considerably from species to species, but as a rough rule-of-thumb, wood undergoes about 8% tangential shrinkage, 4% radial shrinkage, and 0.1% longitudinal shrinkage from the green to ovendry condition. Heavier (denser) woods generally shrink more than lighter woods.
Does wood shrink in winter or summer?
Over time, most treated lumber will shrink slightly across its width as it dries out. Take this small amount of shrinkage into account when laying decking or fence boards. After being outdoors for six to 12 months, treated lumber will develop cracks, called "checks," along the surface of each board.
Where does most wood shrinkage occur?
Wood expands and contracts with changes in the surrounding humidity and to a lesser degree the temperature. More humid air will cause wood to expand; drier air will cause wood to contract. This movement cannot be stopped.
What are the three types of wood shrinkage?
For those with boards that are already cupped, you could try unscrewing those boards, and then you can flip those boards over and screw them back into place. Make sure that a minimum of two screws are used on both sides of your decking boards. Longer screws are also preferred for an easier fastening process.
How long does it take deck boards to shrink?
To keep your deck boards from cupping and splitting, it needs to be installed correctly: 1) two fasteners at EACH support (screws are better than nails and they should penetrate at least 1 1/2” into support), 2) keep fasteners about 3/4” from edge of deck board to keep it from cupping, 3) pre-drill fastener holes at ...
How do you stop wood from expanding and contracting?
What causes wood to shrink or swell?
How do you fix cupping deck boards?
How much does treated decking shrink?
How do I stop my deck boards from cupping?
Over time, most treated lumber will shrink slightly across its width as it dries out. Take this small amount of shrinkage into account when laying decking or fence boards. After being outdoors for six to 12 months, treated lumber will develop cracks, called "checks," along the surface of each board.
How long does it take deck boards to shrink?
Generally, six screws placed the length of your board will keep the board flat and secure. Use two screws at either end of the board and two more towards the outside of the board at every joist. This will keep the boards in place, giving them no room to move or warp.
How do I keep my deck boards from curling?
Keep the Ends of Your Deck Boards Square
To make the ends of your decking square, lay a carpenter's square on the last board where it hangs over the end joist. With a pencil, mark several deck boards along your carpenter's square. To continue this line along the whole deck, snap a chalk line.