Exterior paint: linseed oil or latex?
dipolojarvi
| Posted in General Questions on
Hello,
I’m repainting my old farmhouse, which tends to have peeling paint issues. (1859s balloon framing with clapboards, wall repainted five years ago is starting to peel).
I’ve read a lot about Albeck and other linseed paints. I didn’t see much here about these alternative paints.
Does anyone have thoughts about what the best options are for exterior paint?
I’m in zone 5 mid coast Maine.
Thanks for your help,
Ilmari
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Replies
paint peeling is often due to moisture in the house migrating out through the wall; when it gets to the impervious paint, it pushes it out of the way. Do you have a wet basement by any chance?
A paint that breathes might work better than one that does't, but the bottom line is that most paints will peel in the right conditions.
Instead of paint, use a stain. As a rule are stains more vapor permeable, and do not peel. Some stains are designed to be VERY vapor permeable, eg:
http://www.keim.com/Mineral-Story/Vapor-Permeable
(Not an endorsement- I've never used this product.)
Staining over pre-existing paint won't fix the vapor permeance issue, but stripping the most compromized paint sections with a grinder/sander first and applying a solid stain can work. Eventually the still adhered paint may fail, but with the additional drying capacity offered by the stained sections it'll take longer. If/when more paint peels, strip what you can, and re-stain.
If you prefer to paint, exterior latex is fairly permeable, and would offer more drying capacity than oils.
The uneven drying of the siding is part of the problem. When the back side of the siding isn't painted the back side takes on and loses moisture much more quickly than the painted side. This not only increases the peak moisture in the wood under the impermable paint, which when heated by the sun produces some pressure against the paint, it also causes shrinking/contraction and temporary warping of the wood, which works on breaking the adhesion.
Anyone have experience with the Rhino Shield product? Advertised as "far superior to latex paint" due to proprietary elastomeric components, along with a much thicker application. A homeowner in my town just contracted the painting of their huge Victorian with this product, on the basis of a 40-year warranty from the installer (you have that in writing? I asked) and the usual claims about the amazing insulating and protective properties of the product. Their prep work was some lackluster scraping and copious application of caulk in every crack and seam. Any online documentation of the validity of any of these claims? (BTW, this is CZ 5 and the house has seen no envelope improvement beyond blown-in cellulose decades ago.)
Seeing "old farmhouse" and then a recommendation for grinding/sanding raises concerns about lead paint. If you haven't, test or get tested what is there now, being sure to get all the layers, as it may only be the middle layers that have lead. Consider also testing the soil around the perimeter of the house.
Ilmari,
Charlie is right: removing exterior paint from an old house with a grinder can be very dangerous for the health of the worker operating the grinder, and can lead to dangerous deposits of lead in the soil around the house. That puts children who live in the house at risk of lead poisoning.
Stain is just thin paint -- so switching to stain isn't really a solution if you want a painted exterior. If you want to maintain the exterior paint on your home, here is the standard advice:
1. Hire a contractor who follows the EPA’s Renovation, Repair, and Painting (RRP) rule for lead-safe work methods to prep the siding. (For more information on the RRP, see Managing Lead Paint Hazards.)
2. Use a quality exterior latex primer and paint.
It's harder to maintain the exterior paint on insulated walls than uninsulated walls (because siding stays warmer and dryer when walls are uninsulated). It's not unusual for wood siding to need repainting every 7 years. If this prospect is daunting or unaffordable, you might want to consider new siding -- some type of siding that doesn't require frequent repainting.
I wouldn't put much faith in a 40-year paint guarantee until I had talked to a homeowner who tried to get the company to honor the guarantee.