Seasoning (Drying) Wood Siding

Ideally your siding will have been properly seasoned before it is sold and will be almost ready for it first coat of paint (primer), stain or other treatment as soon as it is  installed. However depending on the type of siding and the lumber mill producing the siding, this may not be the case.

Wood that is properly seasoned for painting generally means that the wood has been dried from its "green" condition (high moisture state of new wood) to a more equalized state to where the moisture content of the wood will hopefully remain within a certain range of this drier condition. The lumber companies have methods to accelerate the seasoning of lumber such as the use of a kiln. Any unseasoned siding that has been applied to a building would not be in an ideal condition for painting at that point, and any primer that is applied may not form an adequate bond to the wood. Letting new wood siding weather after it has been installed was often a recommended procedure, but recent scientific studies have shown that the affects of ultraviolet light from the sun on the unprotected wood will eventually cut the paint bonding properties of that surface. This tends to suggest the sooner the wood it painted, the better; which is not always the case if the would has not been seasoned prior to installation.

We would recommend using wood siding that has been properly seasoned prior to installation, and applying the first coat of paint as soon as reasonably possible or before 4 or 5 weeks.

If the siding has been applied green (unseasoned), we would recommend letting the siding weather prior to painting. Several months are often recommended for cedar, some painters wait 6 months. The time it takes to adequately dry out unseasoned wood siding after it has been installed depends on the weather conditions. Rainy damp weather or warm humid weather will slow the seasoning process, while dry windy conditions may accelerate it. When the wood siding has adequately dried, its good to wash any sign of mildew or heavy soiling and allow several more good drying days to take care of the superficial moisture.

At this point you can apply a coat of primer, or to take it a step further sand the surface with a coarse 60-100 grit paper and just dust of the siding with a dust brush prior to priming. The affect of sanding the wood should help to eliminate some of the ultraviolet causes and increase the strength of the primer bond.

If the wood siding has been applied that has been pre seasoned by the lumber company so that the wood is dry and ready for primer, it will actually pick up moisture from the humidity in the exterior air. In such a case it is be best to get a coat of primer on the wood as soon as possible during or before being exposed to very humid weather conditions to prevent the wood from absorbing an excess amount of moisture before painting. The primer will tend to seal moisture out, to a certain extent.

Moisture meters are hand-held devices that can give an immediate reading of the woods moisture content. They may be available at stores that sell paint or woodworking. supplies. It is generally recommended not to paint wood siding that contains over 15% moisture.

Ideal Weather

Usually a house does not get painted during the best possible time of year for painting. Where the humidity changes from season to season you would do best if you could paint in comfortable temperatures and low humidity. For an example: the North Eastern United States tends to have some very nice painting weather during the fall when the high temperatures may be in the 60s and 70s F, and the humidity is lower than in the summer. The lower humidity allows the wood to dry more thoroughly and it also prevents new seasoned wood from absorbing to much moisture. Of course these nice weather conditions do not last long and if there happens to be frequent rain spells around this period of time the wood may not have time to thoroughly dry between rain storms. Getting a coat of primer on bare wood while the moisture content of the wood is low may be a critical factor of a long lasting paint job, as excessive moisture in the wood will will eventually make its way to the exterior air and can loosen some of the primer in the process, thus... pealing paint.