Home>Discussions>EXTERIORS>How to prep preprimed siding for paint after installation a year ago
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Kemahaff
How to prep preprimed siding for paint after installation a year ago
Kemahaff

So we had preprimed cedar siding boards installed over a year ago and didn't get around to painting it. I'd like to do so now but am unsure how to prep the siding. Spray it down with a pressure sprayer, or scrub it? The siding is in great shape and only has some dirt/splash marks near the ground in some places.
:confused:

A. Spruce
Re: How to prep preprimed siding for paint after installation a year ago
A. Spruce

You will need to wash the house down before painting. DO NOT use a pressure washer, as it is too aggressive and will peel the wood, unless you can regulate the pressure way WAY down. It would be better to use a garden hose and scrub brush.

Figure that you should primer first, this is going to encapsulate any dust/dirt you miss and provide a good base for your top coat. Then, topcoat with any good quality exterior latex.

Kemahaff
Re: How to prep preprimed siding for paint after installation a year ago
Kemahaff

Thanks for the reply...just to confirm, the siding already has primer. Does that change anything?

Should soap be used?

A. Spruce
Re: How to prep preprimed siding for paint after installation a year ago
A. Spruce

No and no.

After a year with no paint, there isn't much left of the original primer, plus, it's covered in dirt and grime. While washing will remove some of it, it won't remove all of it. Primer is going to reseal the surface and encapsulate any remaining dirt so that the paint adheres better and lasts longer.

Soap will leave a residue behind that will affect adhesion, so don't use any. It might be possible to use a deck wash or something similar, however, I do not know enough about those products to recommend doing so.

With any luck, Ordjen, a fellow contributor and paint expert will be along soon to chime in on your project.

Mastercarpentry
Re: How to prep preprimed siding for paint after installation a year ago
Mastercarpentry

Clean well, rinse well, and prime before paint. Remember that this coat has to support every future coat which makes it the most important one for the entire lifetime of the house. You need a top-quality primer and workmanship here, nothing else will do.

Phil

ordjen
Re: How to prep preprimed siding for paint after installation a year ago
ordjen

Most primers come with the instruction to finish coat within several weeks. They are not intended as finish coats and will deteriorate within a short time. They leach depots to the surface which should be removed. I would concur with my fellow posters: clean and re-prime. Take it easy with the power washer, use it only as a vigorous rinse.

With cedar siding, there is always the concern of having tannins bleed through as yellowish/reddish stains. Tannins are water soluble and can leach through water based finishes. Traditionally, an oil primer would be used to suppress this, but the newer water based primers , such as Kilz Premium, will suppress the tannins, provided 24 hours of cure time is given before the finish coat.

You can have the primer tinted toward your finish coat color, to aid in only having to do a prime coat and one finish coat. If you prime straight white, a darker finish coat may have trouble covering in only one coat.

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