Q & A: Should I Treat Lumber with Oil-Based Stain?

From on March 28, 2008 in Tools and Tips

This week Ron sent us a question that we thought you, our faithful blog readers, would find helpful.

Dear Calfinder,
My stepfather wants to stain non-treated lumber with oil based stain. He changes his mind on color quicker than the wind changes direction. His comment was; “If I don’t like the stain I’ll paint over it with latex.” I have had nothing but problems when I’ve done this in the past. Please send a Should or Shouldn’t and Can list of what preparations need to be taken. Maybe when he sees all the extra work and money it will take from a professional he will wise up.
Thanks,
Ron

Ron,

Thanks for your inquiry. This is an excellent, useful, and, coincidentally, timely question. Just last weekend I built a cedar fence in a friend’s backyard and we had a very similar conversation. Your concerns about using a latex paint or stain over an oil-based stain are not without merit. You definitely CAN use latex over an existing oil-based stain. However, if the proper preparations are not made it can become quite troublesome.

  • You Should Not apply latex paint or stain directly onto a surface that has already been stained with an oil-based product. Especially if the oil-based stain has not had a good amount of time to weather. The latex will eventually peel and the only way to fix it will be to remove the latex coat and start over.
  • You Should clean the surface very well. Remove any dirt, dust, mildew, etc.
  • You Should, particularly if the existing stain is relatively new, lightly sand the surface to be painted, focusing on areas that are extra glossy.
  • You Should use an oil-based primer on the entire surface prior to applying any latex paint or stain to it. Be sure to follow the manufacturer’s suggestions on the can and be ready to paint as soon as the primer is adequately dry. Even if the oil-based stain has had years to weather, it is always your best and safest bet to use a primer. If you are using paint or a solid color stain, you can ask your local paint store to tint the primer to a similar hue as your finish color.

Depending on the size of the area to be painted, your stepfather may be in for quite a bit of extra work, especially if the wind is particularly gusty where you are. Now, I do not want to discourage him too much. What he wants to do is certainly doable. However, being aware of the necessary precautions and preparations is crucial. If you have had problems with this in the past it is most likely because these precautions were not made. Your stepfather’s best option here is to take the relatively small amount of extra time to really decide on a color he likes and can live happily with. Suggest simply painting a small, inconspicuous section of the surface in question as a hands on experiment.

I hope this helps and good luck!

Remember, if any of you CalFinder readers out there have any questions or comments, don’t hesitate! It is our utmost pleasure to respond. Thanks!

Dan