If you're using your own fresh-cut green wood, products designed for dried wood won't work well on the surface. Fortunately, there are specialty products available to help you paint on green wood. With just a little prep work, you can paint right away, avoiding a lengthy wait during the wood's drying period.
It may take at least 48 hours before the lumber is ready for painting. A stain might be applied to further enhance the natural grain of the wood, or may be applied to give a more natural reddish tinge.
If you paint treated lumber before it's dry, you cause the non-painted side to dry faster. And when one side dries faster than the other, you get warping. You're better off waiting until the wood is dry; otherwise, you'll end up with warped wood, peeling paint, and a big project.
Pressure treated wood needs time to dry out before it's primed or painted. You can expect 3-4 months before the moisture levels fully go down. If moisture beads up on the surface, it's still too damp. You'll know the treated wood is ready to paint when it absorbs water instead of repelling it.
Overall, it's possible to paint over wet wood but you need to get the wood as dry as possible before you can paint over it. You can do this by using a hairdryer, paper towels, or any other method. Once the wood is dry enough to be painted, apply two coats of a waterproof paint primer and then apply the paint.
As the green wood dries and ages, it releases natural oils that can discolor paint. Stain-blocking primer prevents these blemishes. Stain-blocking primer is available at many hardware stores and some artist supply stores. Wait for the primer to dry.
Wood: Interior wood should contain no more than 12% moisture prior to painting. Exterior wood may be allowed to contain no more than 15% moisture. When it comes to wood furniture or cabinetry, the moisture content must be as low as 6%.
The traditional rule of thumb is to let the lumber air-dry for one year for each inch of thickness, but this is only a general rule and close monitoring of the lumber, especially with the help of a moisture meter, provides more flexibility.
You should let the wood dry anywhere between three days and a month depending on how big it is and if it is softwood or hardwood. Softwood as well as thinner pieces of wood tend to dry quicker. A well ventilated dry location is best for drying wood.
Wood pressure-treated for painting needs time to dry out before it is painted, which is much longer than kiln-dried lumber. It can take weeks or even months for pressure-treated lumber to dry completely. Water absorbs the wood's surface and it is ready for painting.
Let the boards cure for two to three months to allow the moisture content to stabilize. If you can stack the boards out of the weather (under a patio or in the garage), that would be best.
Building with green lumber for timber frame construction can save time, money and energy. With green timber, you can begin building right away without having to wait for the wood to dry, or having the added cost for kiln drying, which uses environmentally damaging fossil fuels during the drying process.
The fastest way to dry lumber is by kiln with high temperature and high airspeed. These can dry lumber with a thickness of 25 mm in about 10 hours to a moisture content of 18%. However, if you want to dry lumber to a moisture level of 8%, an oven needs about 28 days to dry.
Seasoning or Air-Drying Wood: The One-Year Rule
In fact, expect most types of wood to take about one year per inch of thickness to dry out. If it's a two-inch log, that means you'll need to let it sit outdoors for two whole years before it's dry enough to efficiently burn.
Before any surface will accept paint, it must be completely dry. Use towels or fans to dry pooling water. If you are working in a humid environment, dehydrate the air by running a space heater for at least four hours prior to application.
If you want to build out of 2x4s, build out of 2x4s! Your best bet is to just get it as dry as you can. So the first option is to get a moisture meter. The next option is to let the lumber sit inside for four-eight weeks to air dry.
Regardless of what finish you put on the wood, the surface must be dry. In order to bond with the wood, the finish must be absorbed. If the surface is too wet an oil based finish will be rejected (oil and water don't mix).
This can also be done with some oils instead of water, but I usually just use water for sanding up to 320 or 400, then dry the wood with towels, and apply oil to the surface by hand.
Mostly wood takes no more than one week to dry after rain.
Normally moisture content of the wood will increase around 30% after exposure to rain and once moisture content reaches 15%, we can consider the wood is dry.
Rain will wash wet paint off the surface and paint won't be absorbed into a wet surface. When it is raining outside, the paint will wash away if it isn't dry. The best way to handle this is to be sure to avoid rainy days. If there is rain forecast for significant parts of the day, plan it for another time.
It's advised that you check the weather forecast at least 24 hours before committing to taking on the task of painting a fence. Warm, dry conditions will allow the paint to set and dry better. Too cold and the paint won't dry, and you'd hate for the rain to come along and ruin your efforts just after you've finished.
The answer is dimensional stability and it is one of the main reasons wood must be dried. Wood begins to shrink in width, and thickness when the moisture content starts to get below 30%. The amount of shrinkage varies by species.