Deck Building Materials Guide for Eastern Washington

Eastern WA Deck Considerations

Eastern Washington’s climate — hot dry summers, cold winters, and significant UV exposure — puts specific demands on deck materials. Choosing the right products upfront prevents costly repairs and premature replacement.

Decking Surface Materials

Pressure Treated Lumber

Most economical option. Must use Ground Contact rated PT (UC4A or higher) for any lumber within 6″ of grade or in contact with the ground. For above-grade deck boards, Above Ground rated (UC3B) is acceptable.

• Requires sealing or staining to maintain appearance in Eastern WA’s dry climate.
• Allow new PT to dry for 60–90 days before applying finish.
• Use stainless steel or hot-dipped galvanized fasteners only — standard fasteners will corrode and stain.

Western Red Cedar

Naturally rot and insect resistant. Excellent choice for Eastern WA — handles UV exposure and temperature swings well. More expensive than PT but doesn’t require chemical treatments. Ages to a natural grey without sealing, or can be stained to maintain color.

Composite Decking

Low maintenance, long lifespan (25–30 years), consistent appearance. Three main types:

• Capped Composite — Polymer shell over wood-fiber core. Best stain and moisture resistance. Recommended for Eastern WA.
• Uncapped Composite — Less expensive but more susceptible to staining and moisture over time.
• PVC Decking — All-plastic, no wood fiber. Best for very wet climates — may not be necessary for Eastern WA’s drier conditions.

Framing Materials

Deck framing must be pressure treated regardless of above-grade height. Washington State code requires:

• Posts in ground contact: UC4B minimum (heavy duty ground contact)
• Beams, joists, ledger boards: UC4A (ground contact rated)
• Ledger board: must be flashed and properly bolted to house rim joist

Hardware & Fasteners

This is where many decks fail prematurely. Pressure treated lumber contains copper compounds that corrode standard fasteners rapidly.

• Use hot-dipped galvanized (HDG) or stainless steel for all framing connectors and fasteners
• Simpson Strong-Tie connectors are the industry standard — we stock the full line
• Structural screws (LedgerLOK, TimberLOK) for ledger and beam connections — stronger and easier than lag bolts
• Hidden fastener systems for composite decking — cleaner look, no face screws

Code Requirements

All deck construction in Eastern WA jurisdictions requires a permit. Key requirements typically include:

• Footings below frost depth (24″–36″ depending on location)
• Ledger connection must be engineered or follow prescriptive code
• Guardrails required on decks 30″ or more above grade
• Stair handrails required on 4+ risers

Always confirm with Spokane County, Stevens County, or Ferry County building departments before starting.

We stock everything you need for your deck project. Ask about project pricing for large material orders.