The Disadvantages of SPF Floor Joists

SPF Meaning

• SPF is not one particular type of joist wood. Rather, it can indicate joists made of spruce, pine or fir. Spruce, pine and fir woods are all similar softwoods when it comes to durability, weight-bearing capacity and flexibility. They are so similar that, for marketing and analysis purposes, the three are usually grouped together under one SPF heading.

Cost

• SPF joist cost is based largely on location and availability. If you live in an area far from mills and forests that supply SPF lumber, you likely will have to pay higher prices for it. This can lead to rapidly increasing costs for your flooring projects. Choosing an SPF option may be more expensive in the long run that using another type of lumber like hemlock or Douglas fir.

Elasticity and Duration

• While SPF is used in floor joists because it has good general qualities for support and durability, it may not be the best option for specific projects. When it comes to elasticity, other products like hemlock are rated higher. When it comes to duration, harder woods such as Douglas fir and larch might last longer. For a specific weight-bearing or durable floor, another type of wood could work better.

Grade Mistakes

• SPF joists come in several grades (three common grades and select structured varieties). If you choose the wrong kind of SPF boards for your joists, you could run into major problems later on. A number 3 grade can be half as durable as the top grade for SPF, and the same statistics go for weight-bearing and elasticity.