Wood piling is a mainstay of foundation systems, and with good reason: Long-lasting treated timber piling - especially CCA-treated piling - offers a number of practical advantages over nonrenewable alternatives.
Timber piling is a low cost deep foundation material; it is widely available, readily modified on site, and easily handled; it can be installed at close spacing without delay; it resists deterioration in acidic soils; it neutralizes stray electrical currents; and its taper provides a friction pile in sand. Plus, the CCA treatment results in a leach-resistant pile that is clean-to-the-touch.
Extensive load tests have been performed on pressure-treated timber foundation piles. Design loads as high as 70 tons have been specified, and ultimate loads as high as 235 tons have been carried. Pressure-treated foundation piles provide an economical solution for many soils with insufficient bearing strength.
Codes & Standards
The International Building Code publishes data on timber piling which are summarized below:
| Standards Round Piling |
ASTM D 25 |
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| Treatment | AWPA C3 |
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| Allowable Design Stresses Compression |
1200 psi |
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| Bending | 2400 psi |
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| Allowable Load without a load test |
up to 40 ton (IBC) |
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| with a load test | as determined by test and subsurface investigation |
