How To Repair Porch Railings and Minimize Wood Rot Using Epoxy Coatings

In my previous post, How To Repair Porch Railings and Minimize Wood Rot, I showed you how you can cut new wooden spindles with a subtle angle to allow water to drain from the commonly used wood bottom rails of accents and porch railing systems. Read on to learn how to improve the odds of long term success by adding epoxy products to your toolkit.

When applying epoxy, use a throwaway chip brush and container.

Since the accent rails (or hand rails) are disassembled, you may as well make a little extra effort before reassembly to protect the end grain that we know will wick moisture into the wood, causing rot. To do that, apply an easy to use two-part epoxy to seal the end grain. My preferred product is called Rot Fix, by System Three. 

Rot Fix is low odor, has a simple 1:2 mix ratio of hardener to resin, and has some open time -meaning it will stay liquid for a few minutes or longer in cold temps. The only complexity of two-part epoxy is measuring ratios accurately. With throw away plastic containers, you can easily mark them up for proper measure. Just remember: one part hardener to every two parts resin. Easy.

Why not seal the end grain of sanded (or new) bottom rails while you are mixing some epoxy? It's a good idea because any end grain can wick moisture. It's a little added protection against future rot.

System Three SculpWood is a much better repair material than any box store wood fillers.

It's possible that there will be some holes in the rail bottoms, either from nails or from rot. Make sure the railing pieces are dry to the touch, then scrape out any soft, crumbly wood. It is suggested that you coat all holes with liquid Rot Fix before filling them with System Three's putty, SculpWood. You can add the putty immediately after application of the liquid epoxy. SculpWood's mixture ratio is a simple 1:1. Simply scoop the putty resin from one container and the same amount of hardener putty from the other, mix them well and use a flat tool to spread the mixture.

Rot Fix epoxy putty is easy to manipulate and even easier to mix.

This combination of epoxy liquid and putty, after proper curing, is extremely tough, grips wood with tenacity, can be sanded easily, and then be painted like any other wood. I couldn't repair my house in the woods without it! Use sandpaper sheets or bust out the Feintool and sanding pads to conquer this job quickly.

 

Make sure to pair up the right bottom rails and top boards.

If you have taken down several sections of railings, its a good idea to match lengths up to ensure the rebuild goes smoothly. Because putty work and even paint can conceal the original spindle placement, you can use the screw holes in the 2x4 top boards to space spindles. Otherwise, you can measure railing that is still mounted to the porch and take that as the basis for spindle spacing. 

When to paint is up to you -before or after assembly. After is probably best, although fussier.

We are close to reassembly now that all our pieces are cut, epoxied, puttied, and sanded. As you can see, I have chosen to paint some pieces and not others. Because there was no fixing to be done on the 2x4 top pieces, those received primer and paint ahead of reassembly. The milled cedar pieces, or bottom rails (which are on top in this image), received epoxy on ends, holes were filled with putty, then sanded, primed, and all surfaces painted. 

There are many nail guns out there, but I prefer 18gauge pneumatic guns.

The bottom rail will be taking in brad nails to reattach it to the spindles. The brad holes, quite small, but visible, will get a bit of outdoor rated caulk and then paint. To accomplish this, I use a pneumatic nail gun with small compressor and tank. I've been using this Senco for at least a decade now without any issues. It works well, but I do like the quietness of this Rolair compressor, a model I purchased for my architectural model shop.

The compressor and gallon tank came as a kit with the brad gun.

Carpenters know that a nail is often just a clamp holding things together while the glue dries. Glue holds a lot of things together really really well, but in outdoor carpentry, this is not usually the case. We depend on outdoor rated screws for much of our fastening, although there are instances when screws are not palatable or functional. At these times, we rely on galvanized brads.

For this project, I use one 2 inch galvanized (reduces corrosion) brad to fasten the bottom rail to the spindles. This single brad is used to hold the spindles in place before sinking the more functional, angled brad. This second brad is driven from the side of the bottom rail, upwards into the spindle to give the piece a modicum of downward resistance. These accent rails are not intended to hold much weight, although that hasn't stopped many people from hanging plants or other objects from them!

That slight angle seen where the spindle meets the bottom rail (at top, its upside down!) will help keep railings dry.

There are different routes to reassembly. The best, if fussier, solution is to assemble all three components -top rail, bottom rail, and spindles before priming and painting. Assembling first allows you to putty the brad holes, sand, then prime and paint the whole assembly. A little more time consuming, but possibly the longest lived solution because the brads used for assembly are concealed under the most paint and putty.

I haven't yet addressed how nails and screws can also lead to rot in porch railing systems. We often find some rot where brads pierce the bottom rails to attached spindles. As water accumulates on these rails where nails penetrate the the paint film, the water can travel the length of the nail, deep into the wood. Cold metal of nails or screws can also condense moisture out of the air, covering the metal with dew -inside the wood!

My solution is to angle the spindles to create a slope that reduces the accumulation of water. I add epoxy sealer to limit wicking of moisture deep into the wood. Finally, I prime and paint with a high quality, gloss paint to protect the wood from the destructive action of the sun and moisture.

I have paint preferences, but whatever you do, do not buy the lowest cost paint.

I've been using Sherwin Williams paint for the last four years. I'm a fan of their Resilience line in satin or gloss. It's lower cost than their top of the line Emerald line and it has the same application temperatures down into the 40 degree range. What I truly like is Resilience's early wet time. The paint can collect dew after four hours of dry time. Here, in the woods of Minnesota, it gets moist at any given moment, rain seems to pop up out of nowhere, and Resilience hasn't failed me yet. 

Emerald is a good paint, but when using it on a railing project, several days of rain beginning a day after I painted, despite protection with plastic, led to a failed paint film. I will only use Emerald when I am convinced it will be warm and dry for several days or when painting exterior items removed into the shop, as with this accent rail project. 

I prefer gloss for porch railings -its tougher and I believe it is better at shedding water. Finally, if you are going to spend on Sherwin Williams Paint, do so during one of their many 30-40% off sales and you will save a considerable amount. Once you register with them at the store, you will begin getting postcards letting you know it is sale time.

Guest Post by Artist & Builder -woodwork for the outdoors

Addendum:

Because I mentioned that it is possible to use the very same techniques on the handrail as the upper accent rail, it's useful to add a few more images of the the handrail as there are some minor differences.

 

As you can see here, there is a screw sticking up through the bottom rail of the handrail structure. This screw is used to fasten the spindles from below.  This is the opposite of the top accent rail that was covered in the above article.

The spindles on the handrail will be fastened with screws to the bottom rail -yes, the one that requires draining, Some of those screws can be seen in the above picture of the underside of the handrails bottom rail. The reason for this is twofold. The first is that brad nails would not be strong enough to resist downward pressure from things like someone's foot resting on that lower rail. The other reason is more subtle -the underside of the bottom rail is not visible so brads are not needed to conceal the fastening system.

The top of the handrail -the most expensive component, is not screwed into the spindles at all. It is brad nailed from above, diagonally into the spindles. The bottom of the upper handrail is milled as a channel. This channel accepts 2x2 spindles perfectly. It also provides outward and inward resistance to movement. Two brads are sunk as described to lock it in place -but that is about all they do. As you can see, screws are fasteners used where they are not visible, brads where visible. Brads are never used where strength is mandatory -that is unless the pieces will be glued, an unlikely practice in outdoor woodwork,

*Please note that the tools and products used in this post are the one's I actually use. I do not receive any paid or product support for the links provided.