The Disadvantages of a Flat Porch

The Right Kind of Flat

• Builders may quarrel about whether it is the quality of the floor that distinguishes a porch from a deck. Many agree, however, that a deck is free-standing and merely abuts the house without being connected to it. Spaced planks that prevent snow, ice or rain from accumulating on the floor make sense on a deck. Many homeowners see an attached porch, however, as resembling another room in the house. To reinforce that feeling, tongue-in-groove flooring is recommended, especially for covered porches. This flat flooring is more comfortable underfoot and less likely to cause tripping.

The Wrong Kind of Flat?

• It seems only logical that a porch should be pitched perfectly flat. Builders, however, tend to regard setting that flooring, or any other, in perfect alignment with a centered carpenter's level as a mistake that will require frequent maintenance. They offer a number of reasons for setting the porch floor at a slight (1/4 inch to 1/2 inch) cant, or slope, away from the house. In this case, what may seem wrong is actually the right choice.

Wear and Tear

• While a porch may be solidly attached to a house, it seldom shares such a secure foundation. As time goes on, therefore, the weight of furniture, crowds and heavy use can produce sagging of the porch floor, putting increasing stress on the connections between the porch and house. Canting the floorboard beams slightly may help prevent sagging or at least direct it away from the house, rather than toward it.

Weather Damage

• Weather offers several reasons for a slightly canted porch floor. Rain that is not structurally directed away from the house can pool, causing mold, mildew and wood rot, both on the porch floor and any parts of the house that it touches. A flat porch with standing water presents a potential for seeping indoors -- even flooding. Snow accumulations can cause similar problems, and ice accumulation can stress joints between the porch and house.

Safety

• Pooled ice, snow or rain on your porch can make it dangerous for visitors or family members. Using ice-melting substances may not be practical, given their potential for damaging the floor surface. Sand, while less corrosive, wears away at painted or stained floor surfaces. And failure to take preventive measures can result in a nasty fall. Building a canted floor helps keep floors both dry and safe during harsh weather.