Around here, pressure treated lumber has historically been Southern
Yellow Pine. SYP is one of the stronger construction species, with
fiber stress rating ranging from maybe 1200 up to 1800 or more,
depending on the grade. I've used these numbers for designing decks
On a recent deck project, I was at Home Depot on a Sunday to buy some
PT lumber, when I noticed the stamp on the boards said the species was
Red Pine. Looking up Red Pine, I find the fiber stress rating is under
1000. Dismayed, I called my normal supplier (a real lumber yard), and
asked them what species their PT lumber was.
"Well, Southern Yellow Pine, of course", was the answer.
I wonder how many people are underbuilding their decks because some
retailers are substituting weaker wood for their PT lumber when many
assume they are getting SYP?