What foundation options work with a NORWEH timber frame pavilion?
A solid foundation is the single most important factor in the long-term performance of your timber frame pavilion. NORWEH kits are compatible with three proven foundation systems — each with distinct advantages depending on your site, region, and budget.
Option 1: Concrete Sonotube Footers (Most Common)
Cardboard or fiber form tubes are set in excavated holes, filled with concrete, and cured before post installation. This is the most widely used method across the US and Canada.
- Depth: Must extend below the local frost line — typically 42–48 inches in northern US states and most of Canada; 24–36 inches in the South. Check NOAA frost depth maps or your local building department for the requirement in your county
- Post base hardware: NORWEH recommends OZCO post base brackets embedded in the concrete while it’s wet — these elevate the timber post off the slab surface, preventing direct wood-to-concrete contact and dramatically extending post life
- Cure time: Allow a minimum of 7 days (ideally 14 days) before setting posts on freshly poured footers
- Cost estimate: $250–$400 per footer installed; approximately $1,800–$2,500 total for a standard 4-post pavilion depending on depth and local labor rates
- Best for: Most standard residential lots; the go-to choice where soil is stable and excavation is straightforward
Option 2: Helical (Screw) Pile Footings
Steel piles with helical blades are mechanically screwed into the ground to the required bearing depth using hydraulic equipment. No concrete, no waiting.
- Speed advantage: Installation typically takes 2–4 hours for a 4-post pavilion; you can begin kit assembly the same day
- No concrete cure time: Piles are load-bearing immediately after installation
- Saddle brackets: Pre-mounted saddles at the top of each pile accept OZCO or compatible post base hardware
- Best for: Rocky or difficult-to-excavate soils; sites where concrete mixing is impractical; projects where speed is a priority; areas with high water tables
- Cost estimate: $300–$450 per pile installed; approximately $1,600–$2,000 total — often slightly less than sonotubes due to reduced labor
Option 3: Existing Concrete Slab or Deck Surface
If you have an existing poured concrete patio, poured slab, or structural deck, the pavilion posts can anchor directly to the surface using surface-mount post base brackets.
- Slab thickness requirement: The existing concrete must be a minimum of 4 inches thick and in good structural condition; 6-inch slabs with rebar are ideal
- Hardware: Use wedge anchors or epoxy anchors to secure post base brackets to the concrete; follow manufacturer torque specifications precisely
- Deck surface mounting: See the dedicated deck mounting FAQ for full details on through-bolting into deck joists
- Limitation: Surface-mounted anchors in frost-prone regions can be subject to frost heave if the slab itself is not properly designed; confirm with a local contractor
How to choose the right foundation for your site
Not sure which option is right for your yard? Our team has guided hundreds of customers through this decision. Call us at +1 (866) 610-0610, Monday–Friday 9am–5pm EST — we’ll ask about your soil type, region, and existing site conditions and give you a specific recommendation.