Let’s face it. Wood is the overall best option for porch swings, bed swings, and most patio furniture in general. This is based on factors that consist of cost, strength, look, comfort, and maintenance. For example, steel may be stronger, but who would really consider that comfortable? Composite material may require less maintenance, but it lacks any real character. We can contrast and compare materials all day long, but natural wood would prevail as the most practical solution.
When it comes to finishes, wood is the most versatile. It can be left natural or finished with stain, varnish, paint, epoxy, and so forth. Leaving it unfinished is fine, but you will extend the life of it tenfold by adding a coat of urethane and keeping it varnished over the life of the swing. How often one should reapply depends on the wear of the varnish. If the swing is in direct sunlight every day of the year, you may have to reapply a fresh coat of urethane every few years. If your swing is under a covered patio or porch with light to moderate use, you may only have to reapply a light coat every 5 years or more. Many variables, such as the amount of use, climate, and exposure, will determine when a fresh urethane coat should be applied. A visual inspection and personal preference is the only rule of thumb when determining when to varnish your swing with urethane.