Let’s not talk about lumber prices, it’s too early for that. Instead, let us settle this argument once and for all. Which is the best softwood lumber to construct with? Is it Southern Yellow Pine (SYP) or Spruce Pine Fir (SPF)? This is a matter with structural, constructability and economic implications.
It’s best to begin at the beginning. So let’s review an essential wood property. Specific gravity is defined as the ratio of a material’s density when compared to water. The higher the figure, the greater the density. Anything above 1 will sink and everything below 1 will float. As can be seen in the table below, the specific gravity of SYP is about 24% greater than SPF and 18% greater than DF. The denser structure of SYP contributes to it outperforming other species in bending, tension and compression.
It appears that where strength is needed, SYP is the champ among these softwoods. However, this increased density means greater weight per board. The denser, harder wood may also prove to be more difficult to drive nails or start screws into. If constructing an interior partition on an elevated floor, one could benefit from the increased workability and extreme light weight nature of SPF lumber.
To be clear, when SYP is needed for strength and therefore specified, it SHALL not be substituted with SPF. A beam or compression member that has been sized using SYP will only have a fraction of its intended strength if built with SPF. This can lead to life safety liabilities that no one wants. Consult your local professional Engineer or Architect for any substitution requests.
Author: Enrique Fernández, PE