Floor joist systems
Modern builders have a much greater choice in floor joist systems than ever before. Here are some facts about different systems.
Traditionally, floor joist systems have used dimensional timber. Solid timber beams are quite strong and fairly easy to work with. There are disadvantages, however. As we emphasize sustainability in construction more and more, it is less and less defensible to use large solid timber where alternatives are available. In addition, over time, wood can dry and shrink, leading to creaky floors.
Engineered I-joists can be stronger than dimensional timber, but are made of smaller trees, usually fast-growing trees. For this reason, they are considered far more sustainable that dimensional lumber systems. Because the product is engineered, it is made to very tight tolerances. I-joists don’t shrink over time like timber, so floor systems using I-joists are very quiet. There are disadvantages, however. First, there are times when holes need to be cut in the joists to run wires and other services. Second, if there have been problems with pouring an uneven foundation slab, the slab will have to be corrected before I-joists can be installed.
Metal web joists
A relatively new and very efficient flooring system makes use of metal web joists. Eco Homes own posi-web joists are part of a very cost-effective floor system. They are lightweight, yet robust, provide long-term stability and are very easy to work with. The open web design makes running service conduits, wires and ducts very easy. Posi-web joists can also absorb sound, making this floor system very quiet. Posi-web also allows greater spans than dimensional timber.