Pile Installation
Home Builder’s Guide to Coastal Construction
FEMA 499/June 2005 
Technical Fact Sheet No. 12

Purpose: To provide basic information about pile design and installation.

Key Issues
--Use a pile type that is appropriate for local conditions.
--Have piles designed by a foundation engineer for adequate layout, size, and 
length.
--Use installation methods that are appropriate for the conditions.
--Brace piles properly during construction.
--Make accurate field cuts, and treat all cuts and drilled holes to prevent 
decay.
--Have all pile-to-beam connections engineered, and use corrosion-resistant 
hardware. (See Fact Sheet No. 8.)

Pile Types
Treated wood piles are the most common type of pile used in coastal 
construction. They can be square or round in cross section. Wood piles are 
easily cut and adjusted in the field and are typically the most economical type. 
Concrete and steel can also be used but are less common. Concrete piles are more 
expensive, but they are stronger and more durable. Steel piles are rarely used, 
because of potential corrosion problems. 

Pile Size and Length
Pile size and length are determined by the foundation engineer. Specified 
bearing and penetration requirements must be met. Piles should have no less than 
an 8-inch tip diameter; minimum timber size should be 8x8. The total length of 
the pile is based on code requirements, calculated penetration requirements, 
erosion potential, Design Flood Elevation (DFE), and allowance for cut-off and 
beam width (see figure at right).

Note: Misaligned piles lead to connection problems. See Fact Sheet No. 13 for 
information about making connections t misaligned piles.

Pile Layout
The pile layout is determined by the foundation engineer. Accurate placement and 
correction of misaligned piles is important. Pile placement should not result in 
more than 50 percent of the pile cross-section being cut for girder or other 
connections. Verify proper pile locations on drawings before construction and 
clarify any discrepancies. Layout can be done by a licensed design professional, 
a construction surveyor, the foundation contractor, or the builder. The layout 
process must always include establishing an elevation for the finished first 
floor. Construction of the first-floor platform should not begin until this 
elevation is established (see Fact Sheet No. 4).

Installation Methods
Piles can be driven, augured, or jetted into place. The installation method will 
vary with soil conditions, bearing requirements, equipment available, and local 
practice. One common method is to initially jet the pile to a few feet short of 
required penetration, then complete the installation by driving with a drop 
hammer.

Pile Bracing
Pile bracing is determined by the foundation engineer. Common bracing methods 
include knee and diagonal bracing. Bracing is often oriented perpendicular to 
the shoreline so that it is not struck broadside by waves, debris, and velocity 
flow (see figure at right). Temporary bracing or jacking to align piles and hold 
true during construction is the responsibility of the contractor.

Graphic: 
--Knee Bracing: 3x or 4x treated wood members at 45 degrees to pile and located 
approximately 4 feet below end of pile (see Fact Sheet No. 13)
--Diagonal Bracing: 2x or 3x treated wood members, or steel rods, attached near 
top of pile and near ground

[Textbox]
To avoid costly pile repairs or replacement, measure, locate, and double-check 
the required pile cutoff elevations before cutting off piles.
[End of Textbox]

Field Cutting and Drilling
A chain saw is the common tool of choice for making cuts and notches in wood 
piles. After making cuts, exposed areas should be field-treated to prevent 
decay. 

Connections
The connection of the pile to the structural members is one of the most critical 
connections in the structure. Always follow design specifications and use 
corrosion-resistant hardware (see Fact Sheet Nos. 8 and 13).

Verification of Pile Capacity
Generally, pile capacity for residential construction is not verified in the 
field. If a specified minimum pile penetration is provided, bearing is assumed 
to be acceptable for the local soil conditions. Subsurface soil conditions can 
vary from the typical assumed conditions, so verification of pile capacity may 
be prudent, particularly for expensive coastal homes. Various methods are 
available for predicting pile capacity. Consult a foundation engineer for the 
most appropriate method for the site.

Additional Resources

American Forest and Paper Association (AF&PA). National Design Specification for 
Wood Construction. (www.afandpa.org)

American Society for Standards and Testing (ASTM). Standard Specification for 
Round Timber Piles, ASTM D25. (www.astm.org)

American Wood-Preservers Association (AWPA). All Timber Products – Preservative 
Treatment by Pressure Processes, AWPA C1-00; Lumber, Timber, Bridge Ties and 

Mine Ties – Preservative Treatment by Pressure Processes, AWPA C2-01; Piles – 
Preservative Treatment by Pressure Process, AWPA C3-99; and others. 
(www.awpa.com)

Pile Buck, Inc. Coastal Construction. (www.pilebuck.com)

[End of Fact Sheet No. 12]