10 Tips For Building a Well-Built Deck
Standards and codes for deck-building requirements vary from city to city and county to county, and each inspector’s interpretation will vary. However, each build or replacement in Raleigh should aim to meet and exceed Raleigh building standards under the North Carolina Residential Code (NCRC) Appendix M, not just a recommendation or information you heard.
As a deck builder in Raleigh, NC, we base our recommendations on local regulations and best-build standards, slightly overbuilding to guarantee long-term strength.
Building durable decks doesn’t necessarily add high costs. However, paying extra for a few upgrades will provide a longer-lasting deck that is protected from rot and other failures. Here, we will explain how.
1 Decking & Board Installation
There are many installation methods. While some are controversial, we are sticking to standard requirements for a quality deck, and these recommendations may not apply to fast-paced new construction jobs.
Screw vs. Nail
We explicitly use all Hot-Dip Galvanized or Stainless Steel connectors, hangers, and bolts (specifically G185 or Z-Max coatings). The chemicals used in NC pressure-treated lumber (typically MCA or ACQ) will literally dissolve standard zinc-plated nails and hangers.
The best way to fasten a wood deck board is with 2.5-inch Simpson StrongTie deck screws. Unlike nails, screws will not back out. Even the best nails, such as ring shank, will back out over time. Composite boards are best screwed using a hidden screw system and will not last as long when fastened on the face of the board.
Additional Tips:
Predrilling holes before screwing the edges of deck boards will prevent additional wood splits.
Treating the edges of boards containing less than .12 copper chromate is recommended.
Wood Type
All horizontal deck boards should be ground contact grade treated lumber. Number one lumber will look better, have fewer wood knots, and should come from leading wood manufacturers. Wood sizes range from 5/4×6 deck boards to 2×6 boards for added strength.
Wood Decking Installation
Placing boards with definitive grain orientation, crown-side down, can minimize cupping. However, most lumber will not have this distinction. Therefore, this detail is not essential in most cases, and screws will be used for the few boards that have directional grain patterns.
Composite Decking Board Installation
Composite decking is best screwed using a concealed screw system and should never be fastened on the face of the board.
2 Deck Floor Joists
Floor joists should be 12” on-center for composite decking and not exceed 16″ for 5/4×6 wood decking.
A 2×10 floor joist or wider is recommended to reduce floor bounce and racking. We prefer joist hangers instead of ledger boards when installing a deck substructure. Hangers prevent unwanted sags, movement, or separation over time.
Blocking between floor joists provides additional lateral stability to prevent racking and increases overall floor strength.
3 Rim Joists & Band
A rim joist is found on the outer edge and holds all floor joists together. Single rim joists are a thing of the past in modern builds. Nailing two rim joists together to create a strong front band is important. NC inspectors will look for the two boards to be nailed every 4-8 inches to create a stronger floor and prevent the outer joist from twisting and cupping. This “nailing schedule” is checked during the framing inspection. Screened porches will require three rim joists for added strength.
Band boards connect the deck’s lateral load paths to the home or structure and should be bolted on with 5/8-inch carriage bolts with nuts and washers, or lag bolts, staggered every 8 inches. When additional strength is needed, we use tension ties (like the Simpson Strong-Tie DTT2Z) to connect the deck joists to the home. Building engineers will spec metal corner support brackets referred to as L90’s and L50’s.
Many Triangle homes are brick or brick-front. NC code (and basic engineering) prohibits the use of brick to support a deck’s weight. If you see this on a quote, the contractor isn’t following NC code. You must either use a “self-supporting” (freestanding) design or remove the brick to reach the house’s structural band
4 Footers
All accessory structures must be placed on concrete footers. The load, solid-ground depth, and post placement determine footer dimensions and specifications.
All ground posts should be placed on piers, post anchors, or stand-off brackets. NC code requires footings to be at least 12 inches deep. But specifically for our Raleigh projects, we aim for 18 inches to hit “undisturbed soil”. Concrete piers raise posts above ground level, keeping them drier and helping them last longer.
Consult with a deck builder or refer to the engineer’s plans for adequate specifications on footer and pier specifications. While 12 inches is the legal frost line in the Piedmont, local inspectors (especially in Wake County) look for the “bottom of the hole” to be on firm, unmoved earth. This prevents the deck from sinking as it settles over the first five years.
5 Deck Posts Best Practices
Post is a general term for a vertical wood or metal support bearing weight or load. There are a few types of posts, and they are all installed differently.
Ground Posts
The best wood ground support for a deck is 6×6 treated ground-contact grade lumber. 6-inch posts are rated for taller decks. Do not “toe-nail” beams to the top of posts. Use notched posts with through-bolts or post-cap connectors.
Ground-level posts should be strapped using hurricane ties.
Post Bracing
Post cross-bracing or knee bracing will prevent the deck from shifting side to side. Fastening braces include 2 5/8-inch through bolts, no more than 2 inches from the edge of the post.
Standard knee bracing extends 1/3 the length of the post. However, be advised that inspectors vary in measuring procedures. Some will measure from the ground, and others from the footer. Cross-bracing is needed when the footers are deep or the posts are too close together.
Second-level Porch Posts
Like the lower post, second-level posts will match in size, and metal straps must be installed on both the top and bottom of the post.
6 Rail Posts
4×4 rail posts are a minimum standard and should never be notched. Instead, the entire post must be bolted to the joists using 1/2-inch or 5/8-inch bolts. Rail posts can be placed outside or inside the rim joist. 6×6 rail posts can be notched, eliminating the need for two 4×4 posts at outside corners. Matching ground and rail posts looks more appealing, creating an intentional deck design queue.
The spacing between balustrades cannot exceed 4 inches. So, for wood, we set them on 3.5 inches to allow for shrinkage. Additionally, the bottom plate for handrails cannot be more than 6 inches off the floor.
Stair handrails must be “grabable rail,” which are 2x4s. A 2×6 can be used on the main deck rail caps.
7 Handrail Caps
A 2×6 handrail cap or composite material lasts longer than a standard 5/4×6 deck board. However, handrails for steps cannot exceed 3.5 inches wide.
8 Handrail Balustrades
Handrail balustrades for areas above 58″ cannot be more than4 inches apart. Install a balustrade 3 – 3.5 inches to eliminate minor errors or discrepancies. Each spindle is spaced from the others; spacing greater than 4 inches can require rebuilding everything.
According to the International Code Council, the national standard for handrail height ranges from 34 – 38 inches for safety and visibility. Handrails are available in wood, PVC, glass, aluminum, and stainless-steel cables. Metal and composite materials require less maintenance.
9 Step Building
Stair stringers are cut from 2×12 treated lumber. Stringers are spaced 12-16″ apart, similar to floor joists. The transition from the deck to the steps must be level without any tripping hazards.
The rise of each step ranges from 6 to 7.5 inches. All exits after step termination must meet or exceed 35 inches.
10 Deck Flashing
Flashing areas where a deck meets other structures is among the most critical deck standard building practices. Proper flashing installation includes tucking it behind the siding and draping it between the band joist and flooring.
Aluminum flashing will corrode and react chemically with treated lumber. Plastic, rubber, and specifically treated metals are permissible for flashing treated lumber. We use Copper, Vinyl, or Stainless Steel flashing for the house ledger—never aluminum.
Joist Tape
Joist tape provides additional protection when applied to joists with nail holes and is a best practice when replanting an entire deck floor.
Final Thoughts
In summary, use concrete, bolts, screws, and metal brackets wherever possible. Using larger lumber and water prevention are critical considerations to futureproof your new deck build or repair.
Contact us today for your next deck repair or build.
