Pressure-Treated Deck Building for California Commercial & Multifamily Properties

Less than any other decking material, which is the main reason it’s chosen. The build cost is driven by size, elevation, foundations, railings, stairs, and the hardware grade the material requires — not by the boards, which are the cheapest part. What deserves equal weight is the maintenance cost, because treated decking needs cleaning and re-sealing on a two- to three-year cycle for as long as you own it.

Rates you’ll find published are boards and labour. They exclude foundations, the ledger connection, railings, stairs, and the corrosion-rated hardware treated lumber requires — which on most decks add up to more than the decking itself. We quote scope rather than rate, because a per-square-foot figure isn’t comparable between two bids that included different things.

Only if the maintenance actually happens. Treated is far cheaper to build and needs re-sealing every couple of years indefinitely; composite costs more up front and removes that cycle. Over ten to fifteen years the two converge, and which one wins depends entirely on whether your property re-seals on schedule. We’ll ask about your maintenance history before recommending either, because the honest answer is different for different properties.

The amount of preservative retained in the wood. Above-ground material is rated for framing that stays clear of soil and can dry; ground-contact carries a heavier retention and is required for posts and for anything sitting close to the ground. The two look identical, which is exactly why the wrong one gets used — and it fails early, in the members that are hardest to replace.

Modern treatments use copper-based chemistry that corrodes ordinary galvanised hardware, and every load path in a deck runs through metal. Hot-dipped galvanised or stainless connectors and fasteners are the specification rather than an upgrade. The corrosion happens inside connections nobody looks at, so it’s invisible until something moves.

No — laid tight. Treated lumber arrives wet from the treatment process and shrinks as it dries, so boards installed snug open to an even gap over the first season. This is the opposite of composite, which expands and must be gapped at installation. Crews that apply the composite habit to treated timber leave decks with slots wide enough to lose things through.

Not immediately. The lumber has to dry enough to accept the finish, and the timing depends on the season and how wet the material was on delivery. Sealing too early traps moisture and the finish doesn’t hold. We give you a date rather than a rule of thumb, and it goes into the maintenance schedule at handover.

Yes, where it’s more than six feet above grade at a property with three or more units. Pressure-treated is wood, and those laws govern wood-framed exterior elevated elements — the treatment slows decay considerably but does not remove the structure from the inspection cycle.

Where the property has a maintenance crew that will genuinely re-seal on schedule, and on utility areas — service walkways, back-of-house decks, and access routes where appearance matters less than budget. On resident-facing amenity decks at properties without a reliable maintenance programme, we’d usually recommend a composite surface on a treated frame instead, and we’ll say so even though it’s the more expensive quote.

We’re a CSLB-licensed contractor (#1060736) building treated timber decks across the Bay Area, Central Valley, and Sacramento, exclusively on commercial, multifamily, and HOA properties. Foundations, framing, decking, railings, and compliance documentation come from one crew.