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Repair for an Old Wooden Porch

Construction How-To, Decks May 17, 2017 Sonia








Rescue an old wooden porch from the elements.

By Clint C. Thomas, Esq.

Your house is in a constant state of battle with the sun and rain. The heat from the sun, especially in the hot summer months, wreaks havoc on paint and caulk. Rainwater presents the biggest long-term threat to any manmade structure. Wind and extreme cold temperatures also pose their own threats to houses. Even if a house has an exterior veneer comprised of brick, stone or vinyl, other parts of the house will still be constructed of wood. Porches are almost always made of wood, and many older homes have a porch floor made from tongue-and-groove lumber.

Knowing the devastating effects that water will have on a wood porch, older homes were built so the porch floors gently sloped from the house to the outside edge of the porch. This was done to allow rainwater to run off the porch and not accumulate in puddles that would eventually rot the flooring. In addition to a water-draining design, older homes also had the advantage of being painted with lead-based paint. Now no longer used due to health and environmental concerns, lead-based paint, for all of its negatives, was very durable. Our grandparents would only have to paint their houses every twenty to thirty years. Whereas, our generation is having to repaint about every ten years with 15 years being on the outside extreme.

The porch on one of my houses had taken a beating over the years and was beginning to show signs of serious water-related problems. A couple of the columns supporting the roof were beginning to sink into the floor, and one outside edge is what I refer to as a “problem spot” because of where it is situated. A gable on the main roof of the house channels a lot of water onto the end of the porch roof, which is constructed with a 23.5-degree outside angle of its own. This results in a heavy amount of runoff being blown into this end of the porch.

For this repair project we milled interlocking tongue-and-groove boards from treated lumber to replace the original rotted porch boards.

I decided to replace the entire side of porch flooring with the exception of a roughly 4-ft. span that I could tell was the original porch flooring from when the house was built in 1880. Since this section was still in pretty good shape and was also original to the house, I decided to leave it and only replace what was on both sides of it.

Using a router table helps to ensure a smooth, consistent cut when shaping the profile. The model shown is from Grizzly Industrial (


I am of the belief that the only two materials to use on the exterior of historic homes are pressure-treated lumber or some type of plastic/polymer product. The two porch columns that were sinking into the floor were in good shape since someone else had already replaced their wooden bases with composite bases. Even though the flooring under the base plate was rotting, which caused the posts to sink, the bases themselves were in perfect shape.