How Much Do Deck Boards Shrink?


If the wood is put up dry, it might swell some in the rain, but will not dry much under 12% MC, so lengthwise shrinkage is minimal. Normal shrinkage is 0.1% for many species without juvenile or compression wood. Another factor, away from the juvenile core, which is 15 to 20 rings out from the center, are knots.

How much will a 5 4 deck board shrink?

With cedar 5/4 decking installation should be with 1/16″-1/8″ gap (2-3mm), which will expand to 1/8-1/4″ (3-6mm) once the wood has dried. The reason for the difference spacing installation for the decking is due to shrinkage.

How much do pressure treated boards 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.

Can I build with wet pressure treated wood?

Building With Wet Pressure Treated Lumber (Can It Be Done?)

However, you really want to start building your woodwork project as soon as possible. In theory, yes you can build with wet pressure treated lumber. Any wood – wet or dry – can be used to create wood crafts and structures.

Can I leave pressure treated wood in the rain?

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 I stop my deck boards from shrinking?

You can use a framing nail or a 16D nail to make sure that each board is a uniform distance from each other. However, if you’re building with wet lumber, you should leave boards 1/16” apart, as this lumber will shrink more over time.

Should I use deck boards or 2×6?

2×6 is thicker and is stronger, but is also more expensive. Spacing between deck boards provide a few critical functions. The primary function is to drain water from the deck. Gaps that are narrow (1/8”), can catch debris, specifically on top of the joists, and can be difficult to clean out.

Should I leave a gap between pressure treated deck boards?

Proper deck board spacing should have a 1/8-inch gap after the decking has dried out. If you install your decking using wet boards, pressure-treated decking that has not yet dried out, then you should install them with no gap as a gap will be created as they dry and shrink.

What is the normal gap between decking boards?

Proper Gap between Decking Boards

When installing decking boards, make sure to leave 1/4 to 1/8 inch gaps in between them. This gap will make sure that the deck can breathe, have sufficient drainage, and make it easier to clean. For the gaps, you can use different tools to help you.

Should you stagger decking boards?

Give It a Dry Run and Stagger the Boards

Do a dry run of your boards by laying them out before attaching to the frame. If your deck dimensions are longer than your decking boards, staggering the joints is important when laying decking boards. The staggered boards improve stability and the appearance of the deck.

How long does it take for pressure treated lumber to dry out?

If you buy ordinary pressure-treated lumber from a home center, however, you’ll have to wait anywhere from two to three days for the wood to dry sufficiently before you can apply a water-based semitransparent protective stain.


Why are my deck boards shrinking?

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. For this reason, I usually butt deck boards as tightly together as possible, so that they’ll leave a slight gap when they do shrink.

How long does it take for deck boards to dry?

A basic rule of thumb for DIY deck builders, homeowners, and professional contractors is that roughly 48 hours is an adequate drying time for a newly washed deck. The weather conditions, of course, are a huge factor when considering a deck drying.

Is it better to use 2×6 or 2×8 for deck?

In general terms, joists spaced 16 inches on center can span 1.5 times in feet their depth in inches. A 2×8 up to 12 feet; 2×10 to 15 feet and 2×12 to 18 feet. The larger the deck, the larger the joists. … 2×6 joists should only be used on ground-level decks that do not require, and will not provide for, any guards.

How far can a 2×6 decking span without support?

Decking boards span from joist to joist. If you use 5/4 decking, joists must be no farther apart than 16 inches. Decking made of 2x4s or 2x6s can span up to 24 inches.

Should deck boards be installed crown up or down?

Lay deck boards so that the best-looking face is facing up! Wood is stable when its moisture content is held above 30%(fiber saturation point). As wood dries below 30% it shrinks. Wood shrinks and swells twice as much in the direction parallel to the growth rings as it does perpendicular to the growth rings.

How many screws should I put in decking?

So, how many screws should you put per deck board? Each deck board should be fastened with two screws at each point where the board crosses a joist to ensure the stability and durability of your deck’s surface. Boards should be fastened to rim joists with three screws.

What happens if I stain pressure treated wood too soon?

Staining too soon can lead to the stain not being absorbed by the wood and result in a patchy and failed upgrade for your deck. Make sure the wood has dropped all of the excess moisture before trying to apply stain. Test to make sure that water is absorbed by the wood which ensures this drying process is done.

What is the best sealant for pressure treated wood?

Best Deck Sealers for Pressure-treated Wood

  1. Ready Seal 520 Exterior Stain and Sealer for Wood. …
  2. SEAL-ONCE Nano+Poly Ready Mix Penetrating Wood Sealer. …
  3. #1 Deck Premium Semi-Transparent Wood Stain for Decks. …
  4. Thompsons Waterseal Solid Waterproofing Stain. …
  5. Eco Advance Wood Siloxane Waterproofer Concentrate.

What happens if you paint treated wood too soon?

Yes – you can leave anything unfinished, but it will be just that- unfinished. Even the treated lumber will deteriorate and decay with time (though you could be looking at decades of use still)- and it will happen much faster if it is not sealed with a finisher like stain or paint or water repellant.

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