Plan angled and herringbone decking with matching framing

Choose the pattern with its framing cost in view

Straight decking offers a clear repeated cutting and fastening routine. Diagonal decking can change the visual direction of a space, but a board travels farther between the same joists when it crosses them obliquely. The supporting grid may need to change to suit the decking product.

Herringbone introduces many end-to-side joints and short boundary pieces. It can create a strong focal area, but every end still needs the specified bearing and fixings. Extra backing, more cuts and fitting around the perimeter can matter more than the square footage of decking. Pattern choice should happen before the frame is built.

Choose a pattern and its dimensions

Open Decking and choose Straight, Angled or Herringbone. Straight boards run Across or Front to back. Angled boards use a measured angle from across the deck: 90° runs front to back, while 45° and 135° give opposing diagonal directions.

Herringbone uses square-ended blocks meeting end to side at right angles. Full block length sets the untrimmed pattern pieces; boundary pieces are cut to the outline. Pattern direction rotates the arrangement. It is not a chevron pattern with mitred ends.

Set the decking support target

Joist spacing (O.C.) lives under Match framing to decking. It sets centre-to-centre spacing across the regular joists for the whole deck and shares its value with the Framing tab. Changing it updates joists, supported decking joints and framing quantities; the first joist centre remains separately adjustable in Framing.

Enter Support-spacing target along boards from the requirements for the chosen decking and installation. This measures support-to-support distance along the board, which differs from the perpendicular joist-grid spacing when a board is angled.

The designer shows Joist centres after recalculation and Current support distance so you can compare the proposed spacing with the current layout. Recalculate framing chooses a compatible joist direction where needed and rounds its calculated spacing down to a quarter inch. It does not select a structural joist size or approve a manufacturer’s span.

45° board crossing front-to-back joists:
Along-board support distance = joist spacing ÷ cos(45°)

Example planning target: 16 in along the board
16 × cos(45°) = 11.31 in joist centres
Designer rounds down to 11.25 in

Recalculate joists and backing, then review beams

Press Recalculate framing in Decking, or Recalculate for decking in Framing. The joist grid and first offset change to match the support target, and internal joint backing is enabled. If there are no beams, an initial beam layout is generated.

Existing beams, posts and footing locations stay in place during this recalculation. If the joists change direction, those beams may no longer provide the intended supports. Use Generate beams from joists to replace the beam/post layout, or edit its paths yourself. Review the support messages either way.

Understand which framing action changes which members

Inspect board ends and short blocks

In Framing plan, PB labels mark backing under internal pattern joints. Picture-frame backing supports the border seams; it is a separate control. Use 3D view → Framing to see the support arrangement without the decking hiding it.

Inspect short blocks, end bearing, connections and perimeter cuts. A line of backing in the drawing does not specify its fastening or structural capacity. Angled and herringbone patterns do not receive the simple straight-board fastener estimate; count the selected fixing system and joint details separately.

Compare the actual cuts before ordering

Use Numbered cuts & stock comparisons to inspect the patterned pieces, assigned stock boards, joints and spares. Do not estimate an angled or herringbone order by applying the straight rectangular course-count formula to the overall width.

Field and border profiles are allocated separately. Include usable stock length, saw kerf, product-specific gaps and an appropriate spare allowance. Breaker-board layouts, fascia and stair materials remain separate.

Read the decking purchase list and stock cutting sheet