Trex decking boards are a popular choice for outdoor decks due to their durability and low maintenance requirements. Made from a blend of wood fibers and recycled plastics, they offer a sustainable and sturdy decking option. However, when it comes to gluing these boards, not just any adhesive will do. It’s crucial to choose the right glue to ensure a strong and lasting bond.
Understanding Trex Decking Material
Before diving into the best glues, it’s important to understand what makes Trex decking unique. As a composite material, Trex boards are different from traditional wood. They are less porous and more resistant to moisture, which affects how adhesives interact with them.
The Challenges of Gluing Trex Decking
Gluing Trex decking presents unique challenges:
- Moisture Resistance: The glue must withstand outdoor conditions, including moisture and temperature changes.
- Bonding Strength: It needs to form a strong bond with a non-porous surface.
- Flexibility: The adhesive should allow for some flex as the boards expand and contract with temperature changes.
Many professional contractors have found Trex deck boards extremely difficult to glue. They’ll have initial success then the glue joint fails with minimal impact or in a short amount of time in use. Most contractors after trying several attempts at gluing Trex boards now refuse to do it again.
Top Glue Choices for Trex Decking
- Epoxy Resins: Epoxy is another excellent option. It forms a strong bond and is resistant to water and chemicals. However, it is important to use a quality epoxy West Systems has done some testing on Trex deck boards in most cases they found the board failed and not the glue joint. You can read West Systems test results: West Systems Trex Test Results.
- Polyurethane-Based Adhesives: These glues are known for their strong bonding capabilities and moisture resistance. Products like Gorilla Glue and Titebond III Ultimate Wood Glue work well with Trex decking. They are waterproof and can withstand temperature fluctuations.
- Construction Adhesives: Certain construction adhesives, like those from Liquid Nails or Loctite PL Premium, are formulated for outdoor use and can bond well with composite materials. They offer the advantage of easy application and quick setting times.
A note on polyurethane glues like Gorilla Glue:
Many have recommended the use of polyurethane glues like Gorilla Glue. Even Trex support staff has recommended it when asked but their stance is usually avoid gluing if you can.
Many have experienced glue joint failure in a short time using these glues. Additionally these glues foam up as they cure so you need to be careful as it will foam up and get on the face of your Trex deck boards.
Gorilla Glue states the following on their website:
Will Gorilla Glue bond plastic/vinyl/rubber?
“Gorilla Glue will work well on many types of plastic; however, we do not recommend for use on polypropylene (PP) or polyethylene (PE) plastics or any type of rubber with high oil or plasticizer content.“
Trex decking is made with polyethylene therefore it would not be recommended by Gorilla Glue.
Application Tips for Best Results
- Surface Preparation: Ensure the decking surface is clean and dry before applying the glue.
- Correct Application: Follow the manufacturer’s instructions for application. Typically, a thin, even layer is most effective.
- Clamping: If possible, clamp the boards together while the glue sets to ensure a strong bond.
- Curing Time: Allow adequate time for the glue to cure completely before subjecting the decking to heavy use.
Mechanical Fastening
You should never rely on glue alone for Trex decking. Always make sure you have the proper mechanical fasteners securely holding down the Trex deck boards.
Routing Trex Boards:
Many contractors have had better success with gluing Trex boards when they route a finger joint or tongue & groove profile on both boards they are trying to glue. This gives some additional mechanical bonding as well as more surface area for the glue to stick.
Conclusion
Choosing the right glue for your Trex decking is essential for a successful and durable installation. Whether you opt for a polyurethane-based adhesive, epoxy resin, or a specific construction adhesive, ensure it meets the requirements for outdoor use and compatibility with composite materials.
Remember, the specifics about each glue type might change over time, so it’s always a good idea to check the latest product specifications and reviews before making a final decision. Never rely on glue alone and always use the proper mechanical fasteners. Contractors have experienced failure with all 3 glues mentioned please be aware that gluing Trex boards is risky.