It has rained here in Nashville for the past four days and nights. And they say we have another four to go. I spent the day today inspecting a beautiful lake house built just seven years ago. It has over 3,000 square feet of porches on three levels. It was built by a reputable and quality oriented home builder using the best materials. But today the porches are in serious decay. The enemy? Water.
When I first starting learning about structures, I assumed gravity was the enemy. Then, as I focused on porches, I learned that wind was a greater force. A porch is like a large umbrella and we all know what happens to umbrellas in a big wind. But the greatest enemy of all is water. Water rots wood, causes iron to rust and erodes even the hardest stone. Never underestimate the power of even a small trickle of water.
Unlike a house which is built to keep water outside the exterior walls, a porch must be designed to deal with water that will come in. A well-built porch is one that ages well which means it can avoid rot and decay with minimal upkeep.
What are the design elements that keep the water from destroying your porch?
The first thing to do is to keep as much of the water out as possible. There are a few ways to do this. A great way we’ve found is to have large overhangs. Large overhangs shelter the space below helping to keep a buffer between the porch and falling rain. Hip roofs are the best for this. A hipped roof gives overhang and gutters on all sides of the porch. By having gutters on all sides, the rain that does shed off the roof does not fall for the wind to catch and blow onto the porch. The gutters catch the water and channel it through the downspouts to the ground.
The next thing a knowledgeable porch builder will help you do is protect the porch from the prevailing winds. In Nashville, our prevailing winds are primarily from the West so I never build a gable roofed porch with a screened gable facing west. A gable roof is the vaulted style that slopes down on 2 sides and creates the shape of an A. Read more about and see pictures of the different roof styles in our blog post about roof styles.
Because the porch is screened, some water will blow in. Don’t let that water pool – keep it moving! Design your floors to drain. If you are using a deck type floor, make sure the boards have some gap for drainage. And, make sure the area below is sloped so the water runs away from the foundation of the house.
If you have a masonry floor such as concrete or tile, slope the floor so that the water drains away from the house and preferably not towards the prevailing winds.
When using tongue & groove wood floors, run the flooring in the direction of the slope. Many make the mistake of running it perpendicular to the slope causing water to get caught in the cracks between the boards.
Next, don’t block the flow. A gently sloping floors will encourage the water to exit. We leave a slight gap under our porch walls. Any time you let water pool, it will start to cause rot in wood. As long as the water is just passing by, and the wood has an opportunity to dry, it will not rot.
You will want to avoid having completely flat horizontal ledges such as sills, door rails, and other horizontal surfaces. A ledge is simply a place for water to sit and pool. Bevel the outside edges and avoid any flat horizontal area as much as possible.
Finally, use appropriate materials. Some great choices include pressure-treated lumber, Cypress, PVC synthetic decking, metal, aluminum, stones, tile or concrete.
Pressure treated lumber is not the prettiest wood but it sure is functional. From ground up to floor joists, we use pressure treated lumber. Above the floor we use other materials but with great caution and concern following the rules above.
Cypress is such a wonderful wood. I once toured a Frank Lloyd Wright Usonian home in Alabama. It was being restored. The flat roof (basically painted canvas) had leaked and the redwood and cypress exterior was being replaced. The redwood was just rotted through. The cypress was pristine. That really impressed me. Today, most of our porches have cypress flooring.
PVC – I’ve learned to love PVC. It doesn’t rot no matter how much water you put on it. It has limited strength so it’s not for framing. But for non-structural pieces such as flooring and railings, it’s a great choice. It has come a long way aesthetically. While the old synthetic colors and styles looked a lot like plastic, the new colors along with their graining and streaking patterns make it look a lot more like real wood. I love the newest colors of AZEK decking. They are multi toned so they look more and more like wood. We rarely use anything else for decks. For railings, we have developed a line of PVC railings that are just the bomb! Check them out at our new Porch Store. You can even buy them online at our store.
Lastly, metal, aluminum, stone, tile, and concrete are all great materials in that they take less effort to avoid the destructive power of water. But all of them will succumb if you don’t take the other precautions listed above.
The house I looked at today broke several of the rules above. As a consequence, the work to correct the problems will cost nearly $100,000. What a shame. Think before you build. Where is the water going to go? Plan for it and water goes back to being a life giving force, not the enemy.
If you are considering adding a porch to your Nashville area home, give us a call for a free consultation. If you live outside the Nashville market, you can now purchase our PVC railings online for use with your new porch. These water proof railings are not only stunning, they will never rot.