Design Values of Pressure Treated Lumber

[Berniedog]

I have been asked by a Building Official to provide design values for Pressure Treated Lumber. NDS 2001 (4.3.14) states that that "tabulated design values apply ....to lumber treated by approved methods." Does this mean that there are no reductions for design values from the NDS for using Pressure Treated Lumber?

 

[structural01]

Yes. As fas as I know. I've used and specified pressure treated lumber many times. But, never applied any reduction value. The only thing you have to look out for when using PT is it might be corrosive to fasterners and connectors.

 

[JAE]

Or if the pressure treatment required incising (cuts parallel to the grain to increase penetration). There is an incising factor in the NDS Design Specification -

Ci (for E) = 0.95
Ci (for Fb, Ft, and Fc) = 0.85
Ci (for Fv, Fc(perp)) = 1.00

 

[Taro]

Depends what the pressure treatment is for. Fire retardant pressure treatment often requires strength reduction factors.

 

[MongoPac]

Be certain that you specify the PT as DougFir. There are lumber yards out that only stock Hem-fir PT mudsill, which has lower values, (and is actually prohibited in Los Angeles).