Brady-Built Sunrooms often recommends a helical screw foundation for the installation of
sunrooms as an alternative to a concrete pier (often called a Sonotube) foundation. What is it and why use it?
First; it is best to understand what a concrete pier foundation is. A concrete pier foundation requires the excavation of a hole large enough to accept the pier form (usually a cardboard tube).The hole must extend to below the frost line, which in most of New England is set at 48” by building code. Depending upon soil conditions and the weight of the structure that the pier will support, a flared bottom is sometimes required on the pier. This is achieved by using a plastic form under the cardboard tube form that gives the pier an upside down ice cream cone shape.The hole for this type of pier is significantly larger than a straight tube pier. (more…)