PIER AND BEAM ANATOMY
Previously we have touched upon the subject of the different, or to be more precise, the most common types of foundations. Back then, we made a general overview of these types of foundation and their direct comparisons to one another. This time however, and for the following two posts after, we will delve more deeply into the anatomy of each type of foundation.
For starters we know that a foundation is the portion of the structure that lies in direct contact and connects it to the ground. This transfers the load onto the ground, making sure that it provides stability and distributes the load uniformly as to avoid unequal settlement. This also protects the structure against natural forces and provides isolation from ground moisture.
Pier and Beam foundations fall into the category of Shallow Foundations. This is a type of foundation that transfers the structural load near the surface, instead of going deeper into the ground like deep foundations. This means that the width of the entire foundation is grater than its depth. This are less technical than deep foundations, making them more economical and more suitable for light structures.
This type of foundation consists of a series of pedestals, known as piers, usually made of concrete that are embedded into the ground and that support the beams of the home creating a grid system for the structure. These piers have to be spaced evenly every 4 to 6 feet apart.
What this does is to elevate the grid about 24’’ off the ground, creating what is called a crawl space which in turns provides certain benefits, among which is easier access to plumbing and electrical lines for future repairs, keeping the house safe from flooding and making it an ideal option for areas where the soil is unstable.
There are two major things to have in mind with this type of foundation:
First is the integrity of the wood used for piers. Wood, as we all know, decays with moisture and that is why more often than not you will find that cedar posts are used for piers. This wood provides more natural resistance to decay for longer periods of time in comparison with other wood species. It also has a higher resistance to pests and its aromatic oils can ward off insects like termites and other critters.
Drainage is another very important factor to take into account as poor drainage will more than likely provoke foundation issues and movement.
But let us go back a bit and talk about how pier and beam foundations are built. As the name clearly states it these foundations consist of two main elements; the piers and the beams.
First and foremost: a soil analysis is needed to determine that the structure is being built under the right conditions, therefore a structural engineer must oversee the building process. Once the ‘go ahead’ has been given by the engineer the area where the piers need to be placed has to be excavated. A hole has to be dug for each pier and it should be at least 2 feet wide and 3 feet deep. Footings, which are solid bases for the piers are then created with gravel and concrete, with 6 inches of gravel at the bottom beneath the pier. Once the piers are put into place a laser level or spirit level have to be used to ensure uniformity; this will make sure that your home will be stable on the foundation. Next the beams are perpendicularly placed to the piers. These also have to be level to also ensure the stability of the house. To secure the beams to the piers brackets or rebar and concrete are used. Finally the excavated areas around the piers have to be backfilled with dirt, to increase support and keep the piers in place. Grading also comes along this part of the process in order to insure that water will drain away from the foundation.
Now that you know more about the process of building a pier and beam foundation, let’s talk about the pros, as well as the dreaded cons.
We already mentioned that this type of foundation provides natural protection against forces of nature like floods as well as providing isolation from ground moisture. That they are more accessible for whatever plumbing, electrical lines and foundation repairs are required and can be used on pretty much any type of structure and be constructed on most types of soil. Since it is easy to build it does not require heavy machinery, making the build more economic than other types of foundation.
Let’s not forget that foundation problems are a very real and serious issue, irregardless of the type of foundation of your home, and specially in our state. So this is where pier and beam foundations have a great advantage over other foundation types. When foundation damage happens, and it will, the crawlspace will provide a great advantage to the repairs as accessing and replacing the damaged sections or parts will be so much easier.
Now on to the cons. Among the drawbacks are possible infestations given that the crawlspace might provide a cozy living space for insects or rodents, however you can take advantage of that same crawlspace to determine what is going on and deal with this problem. Another drawback , however, is squeaking and creaking floorboards. These of course can be dealt with by positioning shims between the floor joist and floorboards. Not to mention that floors can also feel bouncy if the piers haven’t been spaced appropriately during installation.
Also houses with pier and beam foundation tend to be cooler, due to the air exchange in the crawlspace which might lead to increased energy bills in order to keep the home warmer.
Then, after a while comes the leveling issues, result of decaying piers and settling. Decaying wood becomes soft, bringing about a void between the soil and the solid internal wood; the result is the pier settling and by extension any wood framing that is supported by the pier.
Moisture, however, is the most significant cause of foundation damage in pier and beam foundations. This is not only because of the decaying wood pedestals, but mainly because of the expansive clay soil. This we’ve talked endlessly about, but basically the soil swells when the amount of water that it is holding increases, and then, when dry, drastically decreases, making the foundation move and getting damaged in the process. This can happen due to nearby water facets, problems with plumbing, water drains or roof gutters, but mainly due to seasonal weather changes.
So, what can we do once our pier and beam foundation presents signs of damage and how will this damage be reflected in our home? Well, the most evident signs of damage are doors and windows squeaking or fitting tightly or loosely. Diagonal cracks in walls. Gaps where the walls meet ceilings or floor. Uneven, creaky or bouncy floors. Bowing walls. Sloping floors. Tilting chimneys. These are all signs of alert.
There are several options for repairing the damage. First, if the damage is due to expansive clay soils, then the best plan of action is to ensure that there are no leaks or problems with pipes and drainage. If there are, then fixing these is a priority. Then make sure your drainage is appropriate; that your gutters are clean and free of debris. That your house has a positive grading. All these will help ensure that water is flowing away from your home instead of towards it.
Also, if you have trees less than 10 feet away from your home, you’ll have to install a root barrier as there are two possible ways the tree is causing damage to your foundation; either by lowering the moisture content in the soil or by pushing its roots into the foundation, which could also lead to broken water and sewage pipes.
Retaining walls are also helpful when the soil is too soft to support the weight of the home and can also help by directing the water away from the foundation.
Of course, the main body of work in repairing the foundation will most likely be replacing piers or beams. The damage might come from water/humidity, insects or age. So replacing the damage piers and beams is a must. Luckily this is where that crawlspace will really come in handy.
So in order help maintain your foundation as healthy as possible here are some pieces of advice.
A good drainage system will always be your best ally. This will pull away the water from your home. This could include a sloping yard, known as a positive grading, a proper gutter system, downspouts, french drains, area drains and retaining walls. And make sure that gutters and drains are clear off debris, otherwise they might not provide great assistance.
If trees are too close to the house, then make sure to install a root barrier to protect your house and foundation. Also, try to maintain the moisture levels on your soils balanced throughout the year. A moisture meter will help you out with this; just try and keep the same percentage levels of moisture at all times. In case it is too dry, you can always water your lawn so it will regain its lost humidity. A soaker hose might be a good alternative to help you out with this. If the moisture level is too high then ask yourself why this might be happening; if it is not a seasonal occurrence then try to find out the source of that extra water and act upon it. And given its capacity to retain moisture, mulching might also be a useful tool to help look after your foundation.
In the end, the very best thing you can do to look after your foundation is to work with the experts in the field; either if you need an inspection, foundation repair or additional service do not hesitate to give us a call! We are here, when you need us!