Big Problems Using Concrete Foundation Piers
A concrete foundation pier can be purchased at almost any
lumber yard and home improvement center around the world. They are
usually about 12 inches tall and their base is usually about 12 inches
wide and works its way up, to a 6 inch square at the top and this
usually has two metal brackets sticking straight up out of it. These
metal brackets can be nailed onto the post that will be supporting the
floor framing.
There are plenty of homeowners, handyman and even some contractors who
set these concrete piers directly on the soil, with out any support from
a concrete footing. Over time, if a concrete footing is used, the
foundation pier could actually provide little support for the floor
framing components.
Here is an example of what I'm talking about. You have a section of your
floor that is sagging and you need to raise it and install additional
support underneath these areas to fix the problem.
When you crawl under the house, with your jack and new concrete
foundation piers, you notice the floor framing has a cracked support
beam. Instead of replacing the beam, you simply jack up the floor and
install two foundation pier supports underneath the damaged wood beam
and set them directly on top of the soil.
There is a good chance, over time, that the weight of the house will
push the concrete piers into the soil and you will now be back to square
one.
Here's the solution to your problem, most of the time. Pour a 12" x 12"
wide and 12 inch deep concrete footing underneath the area where the new
piers will be installed. This will provide you with the additional
support necessary, most of the time.
To repair your home properly, you would need to contact a building
professional or a structural engineer to provide you with the exact
specifications of building materials and requirements for your new
footing.
In other words, it's not really a good idea to set a concrete foundation
pier directly on top of the soil.