Decks and patios are fine, except when you planned to spend a lazy summer afternoon enjoying yours and it rains or gets too hot. If only there was a roof… And if there’s a roof, why couldn’t there be screened walls as well, to keep out the bugs? If you follow this logic, it’s easy to understand why porches are so popular.
How Big Should a Porch Be?
Porch size depends on porch function. Many new homes have shallow front porches for curb appeal, four-foot deep vestiges of the wide ones we associate with older homes and past times when people interacted more with their neighbors. For comfortable seating, a porch needs to be at least 6 feet deep. If you’d like a table for outside dining, you need at least 10 feet of depth.
Width depends on the house. A porch can partially cover the front of the house, mainly offering shelter to the front door. It also can run the width of the house or wrap around it. Back porches are often sized like a deck, sometimes with an un-roofed area for the grill.
What’s the Difference Between a Porch and a Deck?
Aside from porches having roofs, the construction is similar. Porch footings have to be larger than deck footings though. That’s because deck footings only have to support the weight of the deck and the people on it. Porch footings have to support those things, and they have to support the weight of the roof as well.
Another difference is the flooring. While a porch can be floored with regular decking boards, that’s not the traditional treatment. Porch floors are traditionally tongue-and-groove (T&G), vertical-grain fir with a painted finish. Present-day variations include T&G boards milled from mahogany or other tropical hardwood, and T&G boards made from plastic composite.
T&G flooring provides a smooth surface that’s easily swept clean. Fir is only moderately rot-resistant, so unlike rot-resistant decking material, tongue and groove flooring traditionally runs perpendicular to the house so that rainwater runs off it and isn’t trapped. That points to two differences between deck framing and porch framing. Decks are usually framed level as water can simply drain between the boards. Porches are framed so that they pitch away from the house so that water doesn’t puddle on the flooring, which would eventually rot it. And since decking usually runs parallel to the house, deck joists run perpendicular to it. For porch flooring to run perpendicular to the house, its joists must be parallel to the house.
What About Building Codes for Porches?
Decks and porches must meet the same code requirements where they attach to the house. There, the ledger board that supports the porch framing must be installed according to the schedule in the International Residential Code (IRC), and it must be flashed to keep water from reaching the house framing.
Just like decks, porches must comply with code requirements for stairs and railings. In most cases, a porch that’s 30 inches above the ground (or higher) will require a railing but check with your local building inspector to confirm this requirement. The balusters in a railing can be no more than 4 inches apart.
If your house is in as so-called Wildland-Urban Interface zone in a region where wildfire is a concern, then the porch will be required to meet enhanced standards for fire resistance.
Porch Posts Can Vary in Style
The posts that hold up a porch roof are both structural and aesthetic. Because they’re structural, they must align with the posts and footings that support the floor framing so that there’s a continuous load path. And the loads aren’t just straight down, as might seem obvious. Because porch roofs are open to the elements, wind uplift must also be considered, and the posts must attach to the roof framing and to the footings below in a way that keeps the roof from blowing off. They should also be detailed to discourage rot.
Aesthetically, the posts should match the house. A rustic lake cabin might just have 4x4s or even peeled logs for posts. More formal porches usually have their posts wrapped with finish materials and moldings. Lathe-turned posts are an option as well, as are columns based on classical architectural styles.
Porch Ceilings Should Reflect the Home’s Style
. A rustic cabin might have exposed rafters, with the T&G boards of the roof above visible from below. More formal porches will often have a flat, beadboard ceiling. If budget and low maintenance are your goals, vinyl soffit material can be used for a porch ceiling. Another budget ceiling is simply smooth plywood with its joints covered by lath strips.
Sometimes porch ceilings are painted light blue, either to mimic the sky or to keep flies from alighting, depending on which architectural old wives’ tale you prefer. White is another favorite color because it reflects light well and brightens the space below.
Screens and Skirting are Popular Options
In mosquito or black fly country, a screened porch is a smart option. There are a variety of ways to screen a porch. The simplest approach is to buy rolls of screen and secure it to the posts with staples and wood strips. You can get a neater look by using one of the proprietary systems of aluminum strips that hold in the screening.
A great option is to have removable panels made that can be replaced with glass ones for a three-season room.
To hide the dark void below a porch from view, skirting is commonly used. Skirting is almost always open enough to provide ventilation to keep moisture from building up below and rotting the porch. Materials can be rot-resistant wood or plastic lattice.
Extra Details Make a Difference
Since they see the most use in the summer, many porches are outfitted with ceiling fans for cooling. It’s important to choose fans rated for outdoor use. Interior fans often have blades made of fiberboard, which can sag permanently when exposed to exterior moisture.
It’s a very good idea to have a number of electrical outlets installed on the wall the house shares with a porch. From fans to table lamps to phone chargers, we plug in many, many things.
Porch swings are fun and are a wonderful nod to more innocent times. If you plan on one, make sure the ceiling framing is beefy enough to support the weight.
In the south where it can be warm enough to use a porch year-round, some people turn a back porch into a second living room. A fireplace, wet bar, and a big screen TV can even make your southern porch the place to host a Super Bowl party!
