Saturday, February 27, 2010

I am painting my old wood siding, can I use an oil primer and latex paint? Which is better?

My wood siding is very old and dry, I want to seal it so the paint won't be absorbed into the wood and it will be better protected.I am painting my old wood siding, can I use an oil primer and latex paint? Which is better?
The only primer to use, in my mind, interior or exterior, is Kilz original. It is oil, actually alkyd, based. Technically they don't make oil-based products anymore. That aside, it is the only primer I recommend - ever.





How old is very old? Also, what is the wood? If it is German pine, it doesn't matter what you do, it will peel. German pine NEVER stops oozing sap, or at least it hasn't in most house I've seen it on (some as old as 1852). However, it wasn't commonly used in homes built in the 20th century.





Get as much of the old finish off the siding. If it is very old, you will have lead-based paint on it. Make sure to wear a respirator when scraping / sanding. Get as much off as possible with scraping so it stays in large pieces. Make sure to have plastic dropcloths underneath you as you work to catch the pieces and keep the paint chips from getting into the ground.





Once that is done, wash with a mixture of bleach and water. Typically 1/4 cup bleach per gallon of water is what is recommended, but unless there are serious moss and/or mildew issues I use 1/4 cup bleach per two gallons of water.





After that thoroughly dries, prime with the Kilz. If you get down to bare wood that is quite dry, do two coats. This, being alkyd-based, cannot be sprayed.





Once the priming is done, you can top coat with whatever you want. Primers do not have the high alkaline levels that paint do, so latex paints will bond to the primer. I would suggest a good, 100% acrylic paint. It will hold it's color better, and will form a nice thick coat on the outside. I would suggest doinng two coats of this as well, although if the right color is used you can get away with one.I am painting my old wood siding, can I use an oil primer and latex paint? Which is better?
No if you use oil primer use oil paint.
use the oil primer.....it'll soak in. and do better......the latex just sits on top. and will get rubbery after a while......
About 5 years ago we went thru this process and had so many suggestions. We had dark green wood siding and stayed with the same color.


We used an oil based primer after caulking and repairing all cracks and holes.


We were able to use an acrylic latex exterior paint over that with great success.


The previous owners had told us they were painting every year. Our 5 year old paint job still looks great!


We contacted an old friend that is in the house painting business and he had recommend the materials.


Good Luck with your project!
I would use oil primer, and oil base paint.
You are on the right track. An oil based primer would be better for sealing your old, dry wood as it is superior to latex based primers for penetrating and sealing this type of substrate. Not to knock anyone, but Kilz would NOT be the primer to use. Kilz is cheap, is not recommended as a whole house primer and it is made to be used indoors or to spot prime outdoors. It will not penetrate as deeply into the wood fibers as a better oil based primer made for this purpose. An oil primer with linseed oil would deliver more of what dry, thirsty wood needs. As for a finish coat, you can use either oil or latex acrylic paints with the latter being much better. Oil is rarely used any longer for exterior painting for a reason. Oil based exterior paints over wood tend to chalk, peel, blister and fade more quickly than a good acrylic paint. The acrylics offer a durable and flexible film, handling the expansion/contraction that exterior siding goes through with temperature changes. Take extra care in doing the necessary prep work in order to build a good foundation for your finish coat and you will be rewarded by not having to it all over again in the near future.

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