How to Protect and Repair Decks from Rot

Deck rot poses a significant threat to the durability and longevity of wood decks. In order to repair wood rot on a deck, you must replace the rotted wood, which can cost thousands of dollars.

To protect against expensive deck rot repairs, homeowners should include a quality deck joist tape, like PolyWall (a division of Polyguard Products Inc.) Rot Shield Joist Tape in the deck’s design. You will tremendously improve your deck’s durability, ensuring the deck will last the lifetime of your house and limit, if not eliminate, deck wood rot repairs.

Deck Wood Rot Repair

PolyWall Rot Shield Joist Tape includes a rubberized-asphalt ‘sticky’ compound with a high-density polyethylene (HDPE) plastic film face. Joist tape protects the long-term integrity of your deck by stopping water damage and preventing corrosion and costly deck joist rot repair. In addition, the brown-colored Rot Shield Joist Tape camouflages under deck boards.

What Causes Deck Wood Rot?

When wood contains a moisture level of 20 percent or more, it creates an ideal condition for wood-eating fungi to grow, leading to three common types of wood rot: white, brown, and soft rot.

  • White rot occurs between 65℉ and 90℉, and causes the wood to take on a whitish or light yellow shade and feel spongy. White-rot fungi break down the wood’s lignin. Lignin accounts for approximately 30 percent of the wood weight, giving rigidity and antimicrobial properties to the wood.
  • Brown (dry) rot appears dry on the wood’s surface. It thrives between 65℉ and 90℉ and will rapidly spread. Brown rot destroys the wood’s cellulose (primary strengthening material in timber), shrinking the wood, turning it a deep brown, and breaking it into small cube-shaped bits—a process known as a cubical fracture.
  • Soft-rot fungi survive in 0℉ to 110℉ and will decompose wood more slowly than white-rot fungi and brown-rot fungi. Soft-rot fungi also breaks down cellulose, leaving a honeycomb-like appearance to the wood.

How to Stop Wood Rot on a Deck

To stop wood rot on a deck, you must eliminate the moisture and poison the fungi.

  • Minimizing wood deck exposure to moisture requires installing a deck drainage system during construction to divert water away from the beams and joints. In addition, regular cleaning of the deck to remove debris and leaves will significantly contribute toward stopping wood rot on decks.
  • Applying boric acid (borate) during wood deck construction or treating an active fungus growth can effectively kill the fungus that leads to wood rot.

How to Repair Rot Damaged Decks

Polyguard recommends you hire an ASHI-certified home inspector or experienced deck builder to inspect the deck for safety and determine your deck’s extent of rot damage. In addition, you can assess the overall condition of your deck with the  North American Deck and Railing Association (NADRA)’s 10-point inspection checklist. You may opt for a new deck, depending on the extent of damage and the cost of repairs.

However, you can repair a deck for minor rot damage by following a few simple steps:

  • Using a 5-in-1 rasp, claw hammer, or chisel, remove the rotted wood – being careful not to damage the surrounding wood.
  • If you cannot remove the damaged wood, use wood hardener, filler or epoxy to strengthen the affected areas.
  • Stain the new boards and wood filler, then seal to protect the wood from moisture.

How to Protect Deck Joists from Rot

To protect deck joists from rot, builders cold-apply self-adhering deck joist tape as a flashing on deck joists and ledger boards. The tape creates a water barrier between non-corrosive galvanized metal hangers and treated lumber, to protect vulnerable wood joists (treated or untreated) from water that could cause them to rot.

Deck joist tape provides a waterproof barrier that prevents damaging water and debris from accumulating in the spaces between the joists and deck boards and joists. Deck joist tape put between treated wood and metal hangers prevents leaching copper (a preservative) from corroding the joist hinges that hold together the deck.

PolyWall Rot Shield Joist Tape is a high-performing deck joist tape that will protect the deck joist’s top, ledger board, and rim joist against rot. The flashing tape also prevents water infiltration, by helping to seal around metal fasteners, screw holes, and hidden deck fasteners, and stopping cracks and corrosion of the metal surface.

Protecting Your Deck from Rot with PolyWall Rot Shield Joist Tape

Protecting Your Deck from Rot with PolyWall Rot Shield Joist Tape

Simple-to-apply, PolyWall’s Rot Shield Joist Tape creates a durable debris and moisture barrier between the joists, ledger board, and deck boards, to prevent water damage and rot and improve the deck’s longevity. Rot Shield Joist Tape blocks contact between the treated wood and galvanized metal fasteners to stop corrosion.

Installing PolyWall's Rot Shield Joist Tape

Installing PolyWall’s Rot Shield Joist Tape will protect a deck’s integrity, aesthetics, and value, and minimize costly repairs to your deck.

Easy to Apply

Rot Shield Joist Tape provides deck builders with an easy, one-step method to protect deck joists from rot and water damage.

Rot Shield Joist Tape comes in wide, 4-inch by 100-foot rolls with a simple-to-apply split release liner. The tape has guidelines (1.25-inches from the edge on each side) to create a clean, smooth installation and a high-quality appearance, to minimize wrinkles and adjustments.

Rot Shield Joist Tape Protects Against Deck Rot

Moreover, deck builders can apply the joist tape in chilly-winter weather and without priming.

Rot Shield Joist Tape Protects Against Deck Rot

Properly installed Rot Shield Joist Tape will protect your deck from damaging rot, improve the deck’s integrity and reduce costly repairs. It can also stop corrosion.

Moreover, UV-stable (up to 120 days) joist tape will limit initial callbacks and repairs.

For more on how PolyWall’s Rot Shield Joist Tape can help protect and repair decks from rot and make your deck last a lifetime, contact Polyguard professionals today.