“Most framing lumber today performs differently than it did in years past. With faster-growth trees come wider-spaced growth rings, which reduce the wood’s density and, ultimately, its rigidity.”
Manufactured decking brands like TimberTech have redefined the reliability and versatility of modern decking. From impressive durability to low-maintenance care, manufactured materials offer a wide range of benefits. But to get the most out of innovative products like TimberTech decking, it’s important to move beyond surface-level features and understand the nuances of each material—and the best practices for working with them.
In our TimberTech series, we're joined by Pat Maher, product application manager and head of AZEK University (TimberTech is an outdoor living brand of the AZEK Company). TimberTech is an industry leader in manufactured decking and a longtime Dunn Lumber partner. Pat brings a lifetime of experience in building materials, with 20 years focused specifically on manufactured decking. We’re excited to share his unique and seasoned perspective.
At a glance
In today’s episode, Pat explains why leveling your deck framing is critical before installing TimberTech decking. Learn why manufactured decking requires a perfectly in-plane surface, what can cause flexing and undulating in PVC and composite decking, and best practices for achieving a strong, rigid substructure—including sorting lumber, identifying crowns, using joist hangers, and adding blocking for stability.
Watch the video above, or read a summary of our conversation below.
Framing best practices for manufactured decking
Did you know manufactured decking is not a structural product? When approaching your next deck project, it’s essential to know how to assemble the deck framing in a way that provides a level (in-plane) and rigid surface for the installation of your manufactured decking. Wood decking products are more rigid than manufactured decking, making them slightly more forgiving of subtle variations in joist height. Composite and PVC decking, however, are significantly more flexible and prone to flexing around uneven joists, leading to undulation.
When working with wood, the first step to building a solid, in-plane framework is choosing quality treated lumber. Once you have your lumber on site, you will want to sort your joist material and identify the “crown” so you can install them crown edge up. (The crown refers to the subtle, natural curvature of the board when looking down the length of the board's edge. If you see a slight hump or dip along the edge, this is considered the crown.)
Before installing your joist hangers, place the top edge of the joist even with the top edge of the ledger board and add one fastener to hold it. Then fit your joist hanger around the joist and nail it off. In the video, we discuss a method at 2:42 detailing how to level your joists over beams in your framework. At this point, your joists should be in-plane at the ledger and over any beam runs you have. From there, you can use various tools (string lines, long levels, laser levels, etc.) to help you identify any “high spots” on your deck joists. A power planer can be an effective way to remove joist material in order to get your deck joists in-plane. Remember to coat any cuts with an end-cut treatment and consider using a deck joist tape on the top edge of all your joists and beams for added protection from the elements.
Ensuring a strong, rigid substructure
Most framing lumber today performs differently than it did in years past. With faster-growth trees come wider-spaced growth rings, which reduce the wood’s density and, ultimately, its rigidity.
To increase the strength of your framing, we recommend adding blocking every four to six feet. This helps tie the joists together and creates a stronger, more stable substructure.
Every successful decking project begins with solid, in-plane deck framing. With these recommendations, you’ll be off to a great start.
What to explore next
- Understanding the Difference Between PVC and Capped-Composite Decking
- Proper Installation for Advanced PVC Decking
- Proper Installation for Capped-Composite Decking
- TimberTech Decking Series
- Decking tips, best practices, and more