Porch Foundations

We normally don't think much about porch foundations because usually they are not visible.

But I'm sure you've passed a house or two where the porch was literally falling off the house - sorely in need of porch repairs! There are many reasons for this but one is a poor foundation.

You need to consider the following when determining what type foundation you will need.

• Geography: Where do you live? Unstable water or soil conditions may require deeper porch footings, thicker walls, or reinforced concrete. (Silty-clay soils, as an example, have an extremely poor load bearing capacity). In addition, if you live in areas with prominent frost heaves (which have tremendous force) footings must be placed below the frost line.
• Weight: How much does your porch structure weigh? The foundation must be strong enough to support its weight and the weight of your furniture and guests. We've all heard of accidents where a deck gave out because there were too many people on it.
• Slopes: Foundation construction is also determined by the slope of the area. Flat areas or very slightly sloped areas, still need a good foundation. Even if you have a patio porch, the slab still needs to be stable. Any shifting of the roof can cause consider damage to the home.

In addition, regardless of the slope, always build to ensure water runs away from the structure. For steep slopes, you will need either piers (columns of reinforced concrete) that sit on concrete slabs deep into the ground. On very steep slopes you'll want to have an engineered foundation.

Types of porch foundations

• Pier foundations: usually consist of short columns of either concrete block or poured concrete that rest on concrete pads. Often these are poured as one unit. Wood posts are then anchored to the piers and beams are then attached to the posts.
  
  Piers must be at least 12" below ground or beneath the frost line. We have a great video that shows how a pier foundation is constructed - check it out!
• Slabs: usually consist of a slab of concrete poured at grade.
• Perimeter foundations: usually consist of a continuous poured concrete footing supporting foundation walls that support the structure. They are often used where water is an issue.

Water is the #1 enemy of your porch

• Ensure you have adequate slope away from your home and porch to direct water away from it. If you have water issues, consider installing French drains, ensure your downspouts empty at least 10 feet from your porch, and add channels for water using crushed stone.
• If you have a crawl space underneath your porch consider covering it with plastic to form a moisture barrier
• Ensure your porch floor slopes slightly away from the house to direct water away
• Bevel hand railings
• Use good primer paints and paint; keep up with porch repairs and maintenance
• Ensure you have air access underneath your porch (use vents)

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