Unpainted Cedar Clapboards: "Safe" ?

[Robert11]

Hello:

Live in the Boston area.

Will be having pre-primed Cedar clapboards (the typical horizontal board type) put up on my house that is being re-modeled.

Contractors, being contractors, I am a bit concerned that the job will run into the early Fall by the time it is completed, and ready for painting.

Would appreciate opinions on the following:

a. how "safe" is it to leave the clapboards in the pre-primed, Unpainted, condition thru the winter, and have them painted in the Spring, if necessary ?

b. Just out of curiosity, would the answer be any different if they were not pre-primed, and just the bare Cedar ?

Thank you very much,

[Doug Miller]

Not a really good idea. You may have adhesion problems with the topcoat unless you re-prime them. Certainly you'll want to wash them first.

Sure. It turns the answer from "not a really good idea" into "a really bad idea." Sitting there for months, exposed, the wood is going to get dirty. Neither paint nor primer sticks well to dirt. It's a lot easier to wash dirt off of a primed surface than off of bare wood. In addition, there will be much more weathering of the wood.

Best to paint them before winter. Sherwin-Williams now sells a low-temperature exterior paint that they claim is OK down to (IIRC) 35 degrees, and other paint manufacturers probably do too. That would seem to be the way to go.

And if you use unprimed cedar, make sure to use an oil-based primer.

[dpb]

Basically agree w/ Doug except as much or even more than just dirt is the oxidation and weathering of the primer before the topcoat is applied. Not as severe in the winter as summer, but still not a good idea. I expect if you look at the manufacturer's information for the product they will have a time frame for getting them painted. Typically it would be 90 days or less.