Better-Built Wood Railings
Elegant, site-built, rot-resistant railings don’t have to break the bank.
Synopsis: Aaron Rosburg has repaired many rotted wooden deck and porch railings. In many of these structures, water pools on the flat bottom rail and eventually the railings fall apart. In this article, he outlines a better way to build a wood railing and protect it from water damage: add an angled subrail connected to the balusters with a birdsmouth joint, which will shed water when it rains.
When I started out on my own about 15 years ago, I was doing mostly repair work, and many of those repairs were focused on rot. Fixing wooden deck and porch railings always seems to be on the to-do list, particularly the traditional-style railings in which the balusters land on a flat bottom rail or subrail. Water pools near this susceptible joint and then is drawn into the thirsty end grain of the balusters where it rots the wood and corrodes the fasteners, and eventually the railing falls apart.
On a recent job, I was asked to rebuild a two-story porch on a historic 1800s brick building in my neighborhood. While I was researching some period-appropriate railing designs, I stumbled across an old illustration that detailed what I quickly realized was a better way to build a wooden railing.
The illustration showed balusters with a birdsmouth cut at each end that mate with angled subrails to create a water-shedding joint. Eliminating standing water in this critical spot gives the balustrade a significant advantage over just about every other wooden railing I’ve seen and repaired over the years, but there are some perks beyond that, too. The angled connection allows balusters to be attached with a single fastener on the top and bottom — the preferred method if you want to avoid splitting the stock — yet they aren’t prone to spinning like most…