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 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.
Using Shims to Level the Deck Surface
Install shims or notch joist bottom across uneven joists to level your deck surface.
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.
10 Common Deck Building Mistakes & How to Avoid Them
Building a deck can be a complicated process. Learn how to avoid falling into common deck building pitfalls with tips and advice from the experts at Decks.com.
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.
How to Splice a Deck Beam Over a Support Post
Follow our step by step tutorial for splicing a deck beam over a support post. Never split a beam in the center of a span.
Decks vs Patios: Cost, Pros, Cons, & Comparisons
Learn what factors affect the costs of decking and patios. Discover all the comparisons factors to help you choose the right space for your home with Decks.com.
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.
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.
Tile decking
Installing tile over a standard deck frame in an exterior environment is a recipe for trouble.
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