Squaring the Deck Frame

Once the perimeter boards are in place, you can “square” the deck using two tape measures. This will only work if the form you are testing has symmetrical geometry. In the case of a square or a rectangle, you will measure diagonally from corner-to-corner on both sides. These measurements should be equal. In the case of an octagon, you will need to select two distances from opposite sides of the polygon.
As the joists are added, they should not only add strength and rigidity, but should also, in effect, square your deck if they are cut to the appropriate lengths. Obviously, the more square the frame, the better. Slight tolerances can be adjusted before the joists are installed to prevent exaggeration. Compare the opposite lengths of the perimeter of squares and rectangle forms - these lengths should be the same. Using a square and a 4’ level will also help verify that your deck form is level. You can also use the 3-4-5 rule to verify right angles.
How to Decorate Deck Support Columns
Browse some examples of decorative deck support posts for tall decks.
How to Connect a Notched Wood Post to a Beam
Learn how to install a notched wood support post to cantilevered beam connection using lag bolts, through bolts with washers or structural screws.
Deck Joist Water Protection
Learn about a technique used by many pro builders for wrapping deck framing lumber with a waterproof barrier to prevent corrosion and rot.
Decking Patterns
Installing your decking at a 45-degree angle is a popular style for decks. This can be done to reduce decking seams or just for appearance.
Installing Composite Decking
Learn about how to install composite decking. Topics include expansion and contraction issues and hidden fastener systems.
Picture Frame Decking
Install a picture frame or perimeter board to finish the edge of your deck with style.
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Squaring the Deck Frame

Once the perimeter boards are in place, you can “square” the deck using two tape measures. This will only work if the form you are testing has symmetrical geometry. In the case of a square or a rectangle, you will measure diagonally from corner-to-corner on both sides. These measurements should be equal. In the case of an octagon, you will need to select two distances from opposite sides of the polygon.
As the joists are added, they should not only add strength and rigidity, but should also, in effect, square your deck if they are cut to the appropriate lengths. Obviously, the more square the frame, the better. Slight tolerances can be adjusted before the joists are installed to prevent exaggeration. Compare the opposite lengths of the perimeter of squares and rectangle forms - these lengths should be the same. Using a square and a 4’ level will also help verify that your deck form is level. You can also use the 3-4-5 rule to verify right angles.
How to Decorate Deck Support Columns
Browse some examples of decorative deck support posts for tall decks.
Deck building tools
As with any professional job, having the right tools can make all the difference.
How to Use Shared Load Deck Support Posts
Learn how to support an upper and lower deck using one support post and a larger footing by bolting the lower deck into the side of the post.
Decking Patterns
Installing your decking at a 45-degree angle is a popular style for decks. This can be done to reduce decking seams or just for appearance.
Introduction to Decking
Spacing between deck boards provides several critical functions, such as drainage & drying. Learn how to space and stagger deck boards at Decks.com.
Picture Frame Decking
Install a picture frame or perimeter board to finish the edge of your deck with style.
Explore Articles by Topic

Footings
Information related to installing frost footings for decks

Framing
Learn structural framing methods

Decking
Learn about wood and composite decking materials

Stairs
An in-depth look at the complex issue of how to build stairs

Railings
How to install guardrails and handrails to meet IRC code

Features
An overview on water drainage, benches, planters and lights

Design
The basics of deck design

Planning
Learn about permits and working with contractors

Porches & Patios
Build a covered deck to enjoy all seasons

Ledger
Proper attachment techniques

Care
Maintain your deck to maintain your investment

Materials
An overview on water drainage, benches, planters and lights