Foundation Options for Post-Frame Building

We all believe that the foundation of a post frame building or more popularly known as pole barn or pole building consists of treated wood poles embedded in ground along with concrete etc. But today we have wide variety of foundations available for pole building construction. Close to ten foundation options can be there when it comes to create foundation of post frame building.

Foundation Options for Post-Frame Building

No doubt that pole barn is the most economic type of building besides it being environment friendly and energy efficient. These building can be build with many option to make them suitable for commercial use, industrial use, home use or public use. In case of traditional wood building they must adhere to American Wood Protection Association's standards. This organization also publish a report on life of the different woods used in the building using different wood treatment available.

Many people think that the only option they have is the preservative-treated wood inserted with soil pressure. But today post frame buildings are also supported by variety of other foundation System.



Foundation Option 1

Treated Wood Post or Column with Plastic Barrier System

This method is based on the concept that plastic barrier might not prevent moisture and other environmental factors, so the wood is treated with preservative to make it resistance against moisture which is the most dangerous culprit when it comes to damage to building. The in ground wood is first treated with quality preservative to keep moisture, soil and other fungus away from foundation and keep the foundation firm and strong for years to come.

A barrier is created so that it is made sure that wood or pole has no or little ground/soil contact. And also it will reduce chemical leaching into the environment. Researches has shown that if 2mm thick polythene sheet is wrapped around treated or untreated wood that it will last longer than the wood that is without a polythene sheet. It is also noted that the longevity of treated wood embedded in soil is increased when plastic barrier systems are used.

Foundation Option 2

Treated or Untreated Wood Post or Column with a Wood Encapsulation System

Unlike "Treated Wood Post or Column with Plastic Barrier System" , plastic barrier systems that enclose wood keep the covered portion of the wood completely out of contact with outside oxygen and moisture. Chemical treatment may be optional for interior wall spaces in this type of foundation system as this system is airtight and watertight as well. Research by Barnes and colleagues (2013) led created a unique AWPA specification category that is called “Barrier Protection Systems,” that may not require chemical wood treatment. In this system posts are jagged to make a figuration that a concrete collar can stand by. After this process an airtight and watertight modified bitumen membrane similar to commercial grade roofing membranes is applied. To give complete encapsulation to this modified bitumen at least 0.30 millimeter thick polyurethane barrier is applied to protect it from damage and to ensure complete encapsulation. At last covered portion of the wood/pole is placed in a specially designed oven for curing. The high temperature of oven destroys microorganisms that cause decay.

Foundation Option 3:

Cast-In-Place Concrete Piers

In this case concrete piers are used at each post location along with a heavy steel bracket to give lateral shear and uplift resistance that will ensure that posts are elevated above the soil..Concrete is added within the form underneath to support the post bracket. Alternatively, some brackets may also be wet-set with freshly mixed concrete by filling a forming tube and inserting rebar or anchors affixed to a bracket. Cast-in-place concrete floor, a raised floor system or a dirt or gravel floor can be used in some post-frame buildings built on concrete piers. Additional lateral bracing may be required depending on the shear strength of the steel brackets.

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