We have cedar siding on our house and are ready to repaint/stain, but we do not know how to tell if the current surface is solid stain or paint and oil or latex. How can we test for this to determine the right kind of treatment and primer to use?
Well, if it isn't peeling all over, it's probably stain. It is very difficult to get paint to stick to cedar. It can be done, but it isn't done right, usually.
This is from Sherwin-Williams' web site:
"Q. How do I find out if the paint on a house exterior is latex or oil? Is there a quick test? A. If the old paint is peeling, take a good size piece of the peeling paint and hold the edges of it between your thumb and index finger. Exert pressure on both sides of the chip. If it is very flexible and bends easily, it is probably latex. If it is hard, brittle, and breaks instead of bending, it is most likely oil-based paint. Another way to test the paint is to wet a rag with denatured alcohol and rub the surface of the paint. If the paint softens or rubs off, it is most likely latex. An alcohol test usually will not affect an oil-based paint."
Sometimes it is easier to get paint to adhese to cedar if you simply shellac the siding first. it puts a hard coat on the siding and the paint sticks better and lasts longer.
I have been painting for over 45 years and have encountered just about every type of paint known. Since you have cedar siding which has been finished with a solid color the simplest test whould be answer these questions. 1) Is the surface peeling from the siding and exposing natural, uncolored siding. If Yes, it was paint, not stain. 2) Is the colored surface smooth with little or no wood texture showing through? If Yes, it was paint. If you can see wood texture or grain under the solid color coat, it was Solid stain.
Now, following these determining questions, if you determine the coating was solid stain, DO NOT cover it with primer. If you have spots od tannin and / or sap around knots showing, coat those spots with with white shelac (It actually dries clear). Use of a primer will fill the grain and alter the character of the wood. A good solid color stain, such as Sherwin-Williams WoodScapes does not require priming when covering old stain or raw cedar.
On the other hand, if you are dealing with paint, be it oil or latex, you should wash it completely with TSP and follow all basic prep guidlines for previously painted wood. As long as the old paint is sound (not peeling, crazing or chalking, you should only need to prime bare wood or repaired areas before you apply new paint. Regardless of whether the old paint was oil or latex, if it is sound and clean and not glossy, you can repaint with a good quality latex paint. Not all latex paint is the same. Stick to a good brand name (Sherwin-Williams, Benjamin Moore, Behr, ValSpar or Olympic. The same holds true with stain - a good latex will bond well if the old surface is clean, dry and sound. I just completed a 20 year old log home which had been stained with Sherwin-Williams solid stain about 10 years ago. I used Sherwin-Williams WoodScapes solid stain and got excellent results and bonding. (I also got two more jobs from the homeowner bragging on the job Serwin-Williams and I did.) I hope this all helped. You can tell I am an old painter by the lengthy reply.
