How to Dig Post Holes and Frame a Deck
Dig post footings, set support posts in concrete, and assemble the primary ledger, beams, and joist framework for a sturdy deck base.
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🧰 Required Tools & Equipment
- ✓ Post-hole digger or power auger
- ✓ 4-foot bubble level
- ✓ Circular saw
- ✓ Cordless impact driver
- ✓ Tape measure
- ✓ Speed square
- ✓ Clamps
📦 Materials & Supplies
- ✓ Pressure-treated 4x4 or 6x6 posts
- ✓ Pressure-treated 2x8 or 2x10 framing lumber
- ✓ Quick-setting concrete mix
- ✓ Structural joist hangers and framing screws
- ✓ Gravel for drainage
⚠️ Safety Checkpoints & Warnings
- • Call 811 before digging to confirm utility lines are clear.
- • Wear heavy-duty work gloves, eye protection, and ear protection when operating power saws and mixing concrete.
- • Ensure temporary post bracing is rock-solid before walking near or between posts.
📋 Step-by-Step Guide (6 Steps)
Dig Footing Holes Below Frost Line
Use a post-hole digger or auger to dig vertical holes at each marked layout point. Clear loose dirt from the bottom of each hole and pour in 4 to 6 inches of gravel for drainage. Check depth with a tape measure to verify it meets local frost-depth codes.
- • Clean, circular hole with flat bottom lined with gravel.
- • Tape measure confirms target depth below frost line.
- • Digging shallow holes that sit above the frost line.
- • Leaving loose, unpacked soil at the base.
Set and Plumb Support Posts
Place posts into the holes on top of the gravel base. Secure two 2x4 temporary diagonal braces per post using stakes driven into the ground. Adjust until the bubble level shows true vertical on two adjacent faces.
- • Posts stand upright with two diagonal 2x4 braces anchored to ground stakes.
- • Level bubble is centered on two adjacent 90-degree sides of each post.
- • Only checking level on a single side.
- • Using loose stakes that wobble under light hand pressure.
Pour and Cure Concrete Footings
Mix quick-setting concrete according to package directions and pour around each post. Tamp with a scrap piece of wood to eliminate air pockets, then slope the surface slightly away from the wood to shed water. Allow to cure per manufacturer instructions before removing braces.
- • Concrete filled up to ground level with a slight crown around the post.
- • Post remains firmly plumb after pouring.
- • Adding too much water, weakening the cured concrete.
- • Leaving the top flat or dished so water pools against the post.
Cut Posts and Mount Support Beams
Mark the finished beam height on each post using a level line from the ledger board. Cut the posts to height using a circular saw, then set doubled support beams across the posts. Secure beams to posts using structural post caps or heavy-duty through-bolts.
- • Beams sit flat across post tops or notches, clamped tight.
- • A 4-foot level laid across the beam shows perfectly flat and level.
- • Cutting posts at an angle instead of a square, flat plane.
- • Fastening standard screws instead of approved structural hardware.
Install Rim Joists and Square the Frame
Fasten the outer rim joists to the ledger and beam ends to create the perimeter box. Measure diagonally from corner to corner in both directions; adjust the frame until both diagonal measurements match exactly. Lock the corners using structural corner brackets.
- • Outer rectangular frame fully closed with tight butt joints at corners.
- • Corner-to-corner diagonal tape measurements read identical numbers.
- • Proceeding with interior joists before squaring the outer box.
- • Relying solely on visual alignment rather than measuring diagonals.
Hang Field Joists on 16-Inch Centers
Mark joist layouts every 16 inches on center along the ledger and outer rim joist. Fasten joist hangers using structural connector screws, slide joists into place, and secure through all hanger nail holes. Check that joist tops remain flush across the entire deck surface.
- • Joists run parallel across the frame spaced evenly at 16 inches on center.
- • All joist hanger holes are filled with designated structural screws.
- • Spacing joists from inside-edge to inside-edge instead of center-to-center.
- • Skipping screw holes on metal joist hangers.
Credit: inspired by an original tutorial by Lowe's Home Improvement — watch the original on YouTube.
Don’t have everything?
- No Power auger? Manual post-hole digger and digging bar
- No Speed square? Combination square or 3-4-5 tape measure check