Framing a Deck Parallel to a House

Joist Layout Options: Parallel vs. Perpendicular

On some decks, the joists are laid out in a pattern that is parallel to the side of the house that is adjacent to the deck. This is a typical layout for decks that are attached to houses and may be found rather frequently. A pattern that is perpendicular to this one is referred to as a perpendicular arrangement. This comes in useful as an alternate way for hanging framing members from the wall that you can use instead when you have decided that you do not want to do so for whatever reason. You may use this instead of hanging framing members from the wall.

Read more:  How to create a Herringbone Decking Pattern

You will need to construct beams that extend away from the structure at right angles to it in order to alter the standard course that the joists take as they pass through the house. This will allow you to customize the path that the joists take. You will have the opportunity to modify the path that the joists take as they go from one chamber to the next as a result of this. It is probable that in order to provide sufficient support for the beams, you will need to either construct a post and footing next to the house or even cut into the house itself. Both of these potential courses of action are available for consideration, but the one that will be most beneficial to you will be determined by the specifics of the situation that have arisen. The particulars of the situation are what will determine whether or not this will be a need that must be met at all times, despite the fact that it is quite likely that this will be the case. Because the joists will be installed in a direction that is parallel to the house, you need to be aware that this will result in a change in the way that your decking will run. To put it another way, the direction in which the boards of your deck will run will be altered. You absolutely need to keep this in mind, so make sure that it stays front and center in your thoughts. It is quite essential for you to evaluate and guarantee that you have sufficient preparation for this.

Read more: Sistering or Joining Joists 

You will have a difficult time constructing the deck in such a way that it is adjacent to the house since the deck must first be set over the tops of the joists. Due to the fact that this is the case, you should not have any expectations of being successful in achieving that target. Decking should be constructed at an angle of 45 degrees to the direction that the joists are travelling, as recommended by the standard practice that is typically followed. This is the optimal angle for the installation. This will make certain that the decking is put out in a manner that is perpendicular to the route that the joists are following while they are being relocated.

FAQs about Framing a Deck Parallel to a House

What does “framing a deck parallel to a house” mean?

• Instead of joists running perpendicular and hanging off a ledger, you run the joists parallel to the house and carry them on beams that project out perpendicular to the house—usually with posts/footings near the house line to support those beams.

When is parallel-joist framing (no ledger) the better choice?

• When a ledger is risky or not allowed—e.g., brick/stone veneer, hollow masonry, or cantilevered floor overhangs. Codes/guides prohibit ledgers on those surfaces, so a non-ledger (freestanding) layout with joists parallel to the house is typical. It also avoids long-term flashing/leak risks. awc.orgCloudinaryFine Homebuilding

How do I lay out the beams and posts for this approach?

• Add one or more beams perpendicular to the house, supported by posts/footings—often a footing line near the house plus another outboard line. This carries the parallel joists without touching the wall. decks.com

Do I need special footings near the house—and how deep?

• Yes. Many jurisdictions require footings within 5 ft (≈1.5 m) of the foundation to bear at the same elevation as the house footing to prevent differential movement. In frost zones, set footings below frost depth on undisturbed soil

How will deck-board direction and joist spacing change?

• If joists run parallel to the house, many builders run decking at 45° for a clean look. Composite/PVC brands typically require 16″ o.c. for straight decking and 12″ o.c. when boards are ≈45° diagonal—check your product’s table.

Do I need a permit for a parallel-framed (freestanding) deck?

Often yes, but it varies. Some places require permits for all decks; others exempt low decks below a tight height threshold. Always confirm locally before you design. 

How do I manage water at the house if I’m not using a ledger?

• A freestanding layout reduces leak risk because you’re not relying on ledger flashing at the wall. Keep clearances for airflow/drainage and avoid trapping debris against siding.

What bracing is needed (these decks can sway)?

• Provide lateral bracing—e.g., knee braces (post-to-beam) and X-bracing between posts—especially because freestanding frames don’t use the house for stiffness. Follow your local detail sheet.
  
  

Can my joists/beam ends cantilever for a cleaner edge? How far?

• Per the AWC DCA-6 prescriptive guide, joists may overhang a supporting beam up to the lesser of LO or L/4 (¼ of the backspan); beams can also have limited overhangs. Provide blocking and follow the joist-to-beam connection details.

Do guard/rail rules change with this layout?

• No—the height triggers are the same: most IRC jurisdictions require guards at >30 in (762 mm) above grade, minimum 36 in guard height for one- and two-family homes (local amendments may differ).