DEAR TIM: I’m thinking of a career in new home construction and know very little. One of the things I don’t fully understand is the foundation footer. I’m also stumped about piers. What’s the real purpose of these things? Can you install a foundation without concrete footings? What tips can you share about pouring concrete footings? I’m sure you’ve sloshed around in wet concrete down in more excavations than you care to remember. Brad T., Topeka, KS

DEAR BRAD: You bet I can tell stories about concrete footers. Several jobs come to mind, but perhaps the one that stands out the most is the time I had to pour a massive footer for a commercial building with just one helper. Fortunately for me, the job site allowed the concrete trucks access to all sides of the excavation hole, the weather was cool, and my helper that day was lucid. You can’t afford mistakes to happen when you have expensive concrete tumbling in the drums of several 10-yard ready-mix concrete trucks!

Structural engineers, building inspectors and other builders may have more to say about this topic than me, but suffice it to say that a foundation footer is perhaps one of the most critical aspects of the house. It’s almost always the first building element that contacts the earth or soil that the house rests upon. In rare cases, a footer may be supported by piers of one type or another that are placed in the soil under a footer.

A pier is a narrow vertical structural element made from wood, steel, or concrete. The best analogy I can come up with is a table leg. Piers are often used to support a footer that’s resting on poor soil. Piers extend down through the bad soil until they hit bedrock, great soil or create enough friction to adequately support the building’s foundation.

The primary purpose of the footer is to spread out the weight of the structure across a larger footprint than the foundation would if it was in direct contact with the earth. Frequently a concrete footer is 20, 24 or even 30 inches wide and at least 8-inches thick. More often than not you’ll see them 10-inches thick. The average foundation wall is usually only 8-inches thick (wide).

When you calculate the total weight of a completed house plus everything in it, you’d be stunned by the total tonnage. Just the interior furnishings and possessions in an average home can weigh tens of thousands of pounds. Add this to the many tons of weight of the building materials and you end up with enormous concentrated loads. Without a footer under a foundation wall, the wall may actually start to slice into soil much like a knife cuts into a stick of butter.

But a footer, because it’s wider than the foundation wall, displaces this weight over a much larger area. A footer also creates a nice, level surface for the foundation contractor to set his forms.

Some pre-cast concrete foundation systems are routinely installed without a poured concrete footer. They rest on compacted gravel that acts as a footer. Be sure this type of footer is approved for your area and the gravel used is crushed and angular. Rounded gravel might not be a good choice.

Reinforcing steel is a must in concrete footings. Concrete has great compressive strength, but little when subjected to tension. If the ground moves under the footing, concrete can come under tension, crack and displace. The presence of steel dramatically increases the tensile strength of the footer. When overlapping the steel bars, make sure they overlap at least 18 - 24 inches. Structural engineers will specify the best location of the steel inside the concrete footer.

I like to place a keyway in my foundation footers. This is a channel or groove that’s created after the concrete is smoothed over in the forms. You can slide a 2x4 in the concrete to create this feature. When you then pour the concrete foundation, that concrete flows into the groove in the footer. This mechanical connection between the two elements helps keep the foundation wall from sliding across the footer if the foundation wall is subjected to horizontal pressure.

Take the time to ensure the footer is as level as possible. This will make the job of setting the foundation forms much easier. It’s also mission critical that the footer be square so the foundation is centered on the footer. Sigh, so much more to say but there’s just not room!

If you’re pouring a trench footing, be sure to place nails, if possible, in the sides of the trench that tell you how deep to pour the footer. You can also drive steel rods in the center of the trench to help you establish the correct depth of the concrete. Take your time to get the concrete level as it will make it so much easier to pour the foundation or lay concrete blocks that may form the foundation walls.

Concrete footing forms should be made from sturdy 2x8’s or 2x10’s. Many foundation contractors prefer to use 2x8’s and stake them up off the ground several inches. This technique makes it easier to level the form boards in case the excavator was not able to dig a level hole. That’s not as easy to do as you might think.

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Comments: Welcome! I, Tim Carter, don't answer questions here. If you post a question here in the Comments Area, perhaps another visitor will help you. You need to go to the Ask Tim page if you want a question answered. Once there, look closely at how many weeks behind we are. Please be patient as you use this free service. If you have an emergency and need to talk to me, there is an option there for you. Ed Deveney 14 Sep 2010, 14:09 Tim- I have tried and tried unsucessfully to get an answer to my original question to you the other day. You did acknowledge it but nowhere could I find an answer. Tried to go back on ASK TIM, filled out same form again and kept getting booted to another field which then lost the form I filled out repeatedly. My question was and is - can you apply a blacktop sealant over concrete to give the concrete the look of blacktop. I have a portion of my driveway that is cement. Would like it to look like blacktop. Kindly help. Thanks, Ed Deveney. Tom Foster 08 Oct 2010, 10:10 Tim: I am trying to "learn" all there is to know about home foundations. My 2 questions are: 1. When laying out the framework for a foundation, how long and wide would the actual measurements be for a 1600 sq. ft. (square) home? 2. Dow I need to allow an extra measurement for brick to rest on. I do not have a foundation plan. edward russell 16 Nov 2010, 13:16 Dear Tim I have a 90 year old house and need to replace part of the sill. Any suggestions paul klindt 16 Nov 2010, 14:25 Concrete releases a powder that will cause the blacktop sealant to crack and peel. Take a look at this instead: http://www.bestmaterials.com/detail.aspx?ID=15024 We have never used this on any projects ourselves but may in the future. I got this ans. from HouseCalls housecalls@ronhazelton.com> ken weis 16 Nov 2010, 16:55 Tim, I have a brick ranch house. On south end of the house the grass will not grow about 10" out when it gets hot out. What could I put there to look good ....don't want something that I have to maintain . thks, Ken james 14 Feb 2011, 01:23 Tim I am planning to build a 40 x 40 building with cinder block walls in the northeast region of Texas... My question is what should the dimensions of the concrete footer be to correctly support the blocks. The walls will be eight foot in height. the flooring inside will not be concrete and the roof will be metal.      View all comments *Name: Email: Notify me about new comments on this page Hide my email *Text: Security Image: Security Image Text:   Remember, Tim Carter doesn't answer questions here in the comments. You need to go to the Ask Tim page.