As the unrelenting city summer finally gives way to a cooler fall, it’s just about the right time to tackle some outdoor projects and consider the pretty little plants above. They’re the source of one of the most reliably simple and time tested wood treatments in the wooden house owners arsenal of upkeep and repair. This treatment also happens to be one of the most sustainable and earth-friendly wood finishes. Oh, and did I mention, it’s also easy on the wallet?
If you haven’t guessed already, the image of the pretty plant that began this post is flax and if you couldn’t tell from its Latin name in the caption, the product I’m referring to is linseed oil. This happens to be one of the most fascinating derivative uses of the flax plant, which humans have been cultivating and refining on a commercial scale since ancient Egyptian times. It seems that those ancient Egyptians really knew what they were doing too, because few changes have been made to the process of production, refinement and use of this very versatile substance.
The process of creating linseed oil is really quite simple. Seeds of the flowering flax plant are gathered by the millions and compressed by machinery which extracts their fatty oils. This oil is gathered in large receptacles and heated at a precise temperature for a specific duration which causes it to darken and thicken. What you can’t see are the fats and acids combining to form long molecular chains (or polymers) that ultimately give linseed oil its most useful characteristics.
So, how exactly can linseed oil benefit me and my old wooden house? Well, does any of your exterior woodwork look like this:
Deferred maintenance, also known as a few decades of forgotten paint jobs, has left this old porch column looking pretty rough. In fact, those cracks and exposed surfaces will likely lead to insect infestation, mold growth, rot and possibly even structural collapse of the porch roof without attention soon. Thankfully, linseed oil can come to the rescue of this old stalwart of 19th century woodworking. Allow me to explain the repair and hopefully inspire some of you to get outside this fall and do a little exterior upkeep yourself!
In the case of any painted historic woodwork, you’ll want to first check that the paint you’re working around doesn’t contain lead. You can pick up a test kit (for not a lot of money) at any hardware store. This kit will allow you to determine the danger before you get too involved. If you do find lead paint – call the professionals! No sum of money is worth more than your health and safety. So do a little homework first and play it safe.
You’ll want to scrape and sand any loose and flaky paint from the surfaces to be restored. Nature took care of the bulk of that in our example above, but if you’re having a real tough time removing any of yours, don’t worry and move on to an easier patch. If the surface paint is resistant to your elbow grease, it’s likely going to withstand many more years of weathering and will be a suitable base for new paint.
Once the wooden surfaces are sufficiently clear of loose paint you’ll want to apply linseed oil (Home Depot stocks the variety on the right) generously with a clean rag and/or a brush. It’s a good idea to do this with gloves on, as the linseed oil will leave your fingers pretty sticky and maybe even a bit irritated after prolonged exposure. Often times, especially if the wooden surfaces are as dry and neglected as the column above, the linseed oil will soak in so quickly that you’ll think you’ll need another application right away. Don’t rush the process though and make sure to allow this first coat to cure overnight. What you can’t see happening is the oil making its way into all the tiny cracks and pores, filling them with a tough, water resistant barrier that is preparing for another application.
The following day you should check to see if any of the applied linseed oil is still a little damp or sticky. In these areas you’ll want to wipe off any excess and allow for some additional drying time. A thorough second coat can then be applied and allowed to dry overnight once more. Additional coats can be applied, but in many cases, two coats are sufficient.
Something curious about linseed oil is its ability to generate heat as it oxidizes and cures. This makes for a smooth, tough, weather resistant and long-lasting finish onto which paint can be directly applied. A very valuable note though – make sure you don’t bag up your used linseed coated rags or brushes while they are drying. The heat generated can cause them to spontaneously combust. On the architectural elements of you house, a large surface area allows this heat to dissipate, but this isn’t the case inside a tied-up garbage bag. Rags or brushes should be hung out or laid flat to dry before disposal.
From there, the finish paint selection and application style is up to you. Linseed oil works as a great base for most all varieties of exterior paint and helps you use less, as it has filled up all those tiny cracks and crevices that would otherwise soak up excess paint. Its also extra insurance against water infiltration and makes the job of wood boring insects that much harder. And even better, the extra time and effort required by its application means lots more free time before you ever have to paint again!
So, please consider taking a tip from the ancient Egyptians – your old wooden house will thank you!
by Arthur T. Rollin