Lay out deck joists, beams, posts and footings

Choose a support arrangement that fits the site

A dropped beam sits below the joists, allowing them to pass over it where the design permits. This can simplify a continuous joist layout and allow a designed overhang, but it uses more depth below the deck. A flush beam fits at joist level and can help where clearance below is tight; joist ends then need their specified connections at the beam.

A ledger-supported deck relies on a suitable, verified house connection and weatherproofing detail. Freestanding support can avoid depending on an unsuitable house attachment, but brings its own posts, footings and stability requirements. Choose the load path and available space before using even post spacing to tidy the drawing.

Establish the joist direction and ledger arrangement

Mark house edges in Shape, then open Framing. Create framing layout adds the framing layer. For patterned decking, first set the support target in Decking and use Recalculate framing.

Ledger attachment controls whether marked house edges are structural ledger lines or the deck is treated as freestanding. A house edge parallel to the joists does not automatically support their ends. Enter joist, beam, post and footing sizes from the project design; the tool does not choose them.

Choose the right update action

Generate beams from the real outline

Set Target clear joist bay to the layout distance you want to work toward, then choose Generate beams from joists. Perimeter supports follow relevant deck edges, including angles, and deeper bays receive intermediate rows. Recesses split paths where there is no deck.

Generation uses dropped beams and retains entered lumber sizes on matching paths where possible. It removes identical beam rows and joins nearby dropped-beam ends of matching depth and ply count at a shared post and footing. Both beam paths stop at their intersection, and plan and 3D use the same schematic end cuts. Join beam ends & clean overlaps applies this to an existing layout; use Undo to restore it. Interior crossings, flush joints and partial collinear overlaps require a designed detail. The bay target is a layout preference, not an allowable span. The generator has a 12-row limit; support warnings still need review on complex shapes.

Set a beam’s mount and path

Dropped beams sit below continuous joists. Flush beams are at joist level and trim crossing members at the beam faces. Use Beam path to choose Straight row across the plan, Follow a deck edge, or Custom endpoints / angle.

A dropped beam’s edge inset is measured to its centreline. A flush beam’s Outside face inset from edge measures to its outer face; set it to zero to align with the perimeter. For a custom path, enter start/end X and Y or drag the end handles. Angled path lengths and post stations are measured along the beam.

Set and check a joist cantilever over a dropped beam

Position posts and footings

Even spacing balances posts along each beam segment using the target maximum O.C. and the inset from each unjoined end. Joined ends have a post at the intersection instead of two nearby inset posts. Dragging a post switches that row to manual positions. Enter each post centre keeps explicit stations along the beam; a point inside a recess or outside the beam is flagged.

Coincident support posts under compatible beams are modeled and counted once. Shared connections need review, and moving the selected beam or its post does not move the other row. Nearby post and footing clashes are flagged. Posts and footings move with their beam. Choose the post size, footing shape, diameter or width, and base depth below grade. The model uses those dimensions for the layout and view; it does not establish soil bearing, frost protection, footing construction or post connection details.

Add backing and read the schedule

Picture-frame backing follows the selected border edges. Solid blocking rows span the joist bays. Guard backing and seam backers are editable runs, while stair-opening backing follows valid stair openings. Pattern backing follows internal board ends and splices.

Select a joist in Framing plan to read clear spans between support faces and end overhangs beyond the outer support face. Select a beam for post spacing and beam end overhangs. The printed schedule lists members and post/footing coordinates; the material purchase list allocates whole framing boards separately from decking. Defined beam end cuts include their long points in the stock allowance. Shared-junction cuts and bearing still require a reviewed connection detail.

Turn the framing into a purchase list

Use Purchase list at the top of the designer to jump to the material order. Choose framing stock lengths, saw kerf, an extra-length allowance and spare percentage. The list allocates whole boards by entered member size and counts each beam ply separately.

Select support-post stock length after checking actual cut heights and base details. Unspecified sizes stay visible as incomplete rows. Runs longer than available stock require a longer-stock quote or a reviewed splice detail; the planner does not split them automatically.

Enter prices per stock board and review the automatically counted railing posts and assemblies. Add concrete, stair materials, connectors and supplies excluded from those railing quotes as additional items, taking care not to count the same parts twice. Download CSV shares the current order and review notes. Print plan includes the list, and Download project preserves its settings and prices.