The Secret to a Long-Lasting Deck

Updated May 9, 2024 | Posted May 28, 2021 | Professional insight, Product Advice | 0 comments

If you’re building a new deck this summer, you must know this secret to making it last: Protect the foundation with flashing tape. This hidden material, safely tucked over your beams and joists, but just beneath your deck boards, can be the difference between wood that stands up over time and timber that rots due to moisture exposure.

The Secret to a Long-Lasting Deck: Protect the Foundation

The foundation of your deck includes the bearers, joists, and posts that hold up your deck boards. The ledger board is especially important, as it holds the deck to the house, if you have an attached deck.

Water that seeps through the boards onto this foundation will deteriorate the timber fibers over time. While decking boards and rails are usually timber or composite (a blend of timber and plastic material), the foundation is almost always made of timber. 

Did you know that the average deck foundation begins to experience water damage within 8 to 10 years? That’s not long in the life of a home improvement! 

Fight the rot and other dangers to your deck: Flashing tape is one secret to share with your deck builder or to use when you DIY build. Here’s a checklist of what you need to know to protect your foundation. 


Choose a quality flashing tape for Your Deck

The best way to protect decking from rot

During construction, cover your deck foundation with flashing tape. This thin membrane creates a barrier between rain, snow and sleet and your wood. Just as a brolly keeps your head dry in a downpour, so does flashing tape provide great protection on stormy days.  

Another benefit of flashing tape: it keeps your treated wood and galvanised metal fasteners from having a chemical reaction. Treated timber often contains ACQ, which can react with the metal in fasteners. Flashing tape prevents corrosion and holds deck screws tighter. 


Buy Butyl Tape


What flashing tape should you buy? There are three main choices acrylic, bitumen and butyl.  Butyl tape offers a number of advantages over the other two types: It sticks better, doesn’t dry out as easily, endures less stain, resists oozing at high temperatures, can be applied in a wide range of temperatures and is more rubbery, which allows it to flow better around fasteners and screws and create a tighter seal. 

There are several options on the market. Be sure to choose one that’s well made and comes with a warranty. Builders will advise choosing a tape that’s easy to trim and install.

When applying the tape, be sure to purchase one that is not too thin or thick.  With thin tape, you risk long-term durability.  A thick tape may be difficult to install. 


Install The Flashing Tape During Construction


There are just four simple steps to install flashing tape. First, prepare your surface by making sure its dry and at a time when the temperature range is 10˚C or greater. Second, measure the deck to ensure you get the right amount of tape, which generally comes in rolls. Third, cut the tape to the right length and remove the backing for the adhesive. Ensure the tape covers the tops of all joists and bearers. Finally, smooth the tape into place.  

the base of your decking boards

Invest In High Quality Materials

For the deck foundation, you’ll want to use treated wood or varieties that are naturally rot resistant. For the boards, you may choose composite or timber. Composite boards may cost a bit more up front, but will require less maintenance in the long run.  Explore the wide range of colours and textures available, and be sure to use quality hardware. 

The Secret to a Long-Lasting Deck: Protect the Foundation

Maintain Your Deck

 Performing regular maintenance on your deck will also ensure its longevity. Sweep off debris and clean with water and soap at least once a year. That will keep bits of leaves and such from getting stuck between the boards and holding in moisture. If you have a buildup of debris,  you may need to use a putty knife to clean out the deck boards.  

maintaining your decking

If you have timber deck boards, you’ll need to seal the timber every two to five years to make sure water doesn’t seep in and create rot. If you’re not sure when to reapply the seal, add a few drops of water to the boards to see if it soaks in. Like a good car wax, a wood seal should make the water bead up. Composite boards, on the other hand, will not need to be sealed and often come with a 25-year warranty. 

Finally, be sure to inspect your deck at least annually. Look for any darkened wood, soft spots, deterioration at the ledger board, mildew, missing or rusted hardware or signs of insects. Take action immediately to remedy any of these dangerous signs of damage.  

The secret to a long-lasting deck isn’t really so secret: Take care of your deck foundation with flashing tape and regular care, and it will take care of you! 

Updated May 9, 2024 | Posted May 28, 2021 | 0 comments

About the Author

About the Author

Mike Cupit has been in the decorating industry since 2002 and has mostly worked as a Trade Decorator in the domestic sector (peoples’ homes). Self-proclaimed “product geek”, Mike has a passion for paint and decorating tools. Mike now spends most of his time testing paint products and tools, comparing them to similar products on the market, and blogging about the industry in general.


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