Joist Tape Explained: What It Is, Why You Need It, and How Much to Use

It is not easy to build a deck, which make it important to prolong the life span of decking. Moisture prevention is a crucial part in the deck protection. Although people care more about the decking board of the deck, the joist structure beneath the deck determines the lifespan of your deck. Joist tape is a simple and affordable material that help protect the structure of joist. In this article, we will introduce you what is joist tape, if joist tape is really necessary, and how much joist tape you need to prepare.

What Is Joist Tape?

Joist tape is a kind of waterproof tape, commonly used on joist for decking, beam and wall panel to build a moisture prevention shield. It is usually made from butyl rubber or bitumen rubber and is sold in rolls, between 40mm and 75mm wide. Its main function is to form a seal at the top of the joist, preventing rainwater from seeping into the wood through screw holes or gaps, thereby reducing the risk of rot, corrosion and structural damage.

Is It Necessary to Use Joist Tape?

Technically, it is not necessary to use joist tape to build a deck. However, ignoring the usage of joist tape may bring higher maintenance cost. The rainwater will be easily kept at the top of joist. Gradually, the rainwater will seep into the joist through the screw holes or gap, which will cause the rot of wood joist. It is a common issue in wet areas or areas covered with tree shade. Joist tape can help prevent moisture through forming protection over joist. Therefore, it is a worthwhile investment for most family and commercial projects with its low cost and great benefits.

Does Joist Tape really Work?

The answer is yes. Joist tape works excellently in moisture prevention if the joist tape gets proper installation. It effectively blocks moisture, seals screw penetration points, and prevents moisture from accumulating on the wood surface. Many construction workers and project clients give positive feedback after using joist tape, saying the deck get longer lifespan with the help of joist tape. It is noted that the effectiveness of joist tape relies on the proper installation. Ensure the joist is in dry and clean condition before applying for joist tape and choose high-quality butyl tape, which is usually more sticky and durable than bituminous tape.

In short, the benefits of joist tape includes:

• Waterproof and anti-corrosion:: The tape can prevent moisture from penetrating into the top of the joist and the screw holes, reducing the risk of wood rot and metal corrosion, and significantly extending the service life of the deck structure.
• Easy to install: The joist tape is easy to operate, just stick it on the top of the joist, suitable for professional construction teams or owners with strong hands-on ability.
• Low cost, high return: Compared with the high cost of repairing or replacing rotten wood later, joist tape is low-cost and high-efficiency, and is a preventive investment.
• Improve the stability of screw fixing: The joist tape can form a sealing layer around the screws to reduce loosening or rusting caused by rainwater infiltration.

Whether it is a new deck or a renovation of an existing structure, joist tape is a durable protective material worth recommending.

Are There Any Disadvantages of Joist Tape?

Although joist tape is helpful to prevent moisture and costs low, here are some usage points should be noted:

• Require careful installation: Joist tape may not be able to stick to the joist if the joist is wet, dusty or dirty, which affects the waterproof effect. Besides, construction in an overly cold or overheated environment may also affect the adhesiveness of the tape.
• Unable to repair the existing damage: Joist tape can only be a prevention. It cannot repair the wood structure that already be in rot or damaged. So joist tape is more suitable for new-built or sound structure.
• Increase the cost if used vastly: Although the price per roll is not high, for larger deck or multi-level structures, the overall cost will increase due to the large amount used, especially when choosing high-quality butyl tape.
• Cause water accumulation if used improperly: If the tape is wrapped around the entire joist instead of just covering the top, moisture may not be able to drain out and instead accumulate in the wood, creating a potential hazard.

Overall, joist tape is an effective protective product, but to truly be effective, proper installation is essential.

How Much Joist Tape Do I Need?

In order to calculate the number of joist tape needed, the overall length of all joist should be measured. For example, a 3.6m*4.8m deck with 400mm joist spacing distance approximately needs 13 pieces of joists. Each joist is about 4.8 meters, so the overall length of all joists is about 62 meters. Besides, the length of beam and cladding should also be considered. Therefore, it is recommended to prepare more to prevent overlap, cutting and errors.

Joist tape is usually sold in rolls of 15 meters or 23 meters. The width is 40mm to 75mm. The specific choice can be determined according to the size of the joist and whether edging or trim is required.

Conclusion

Joist tape is a simple accessory, but it plays significant role in the durability of deck. It can effectively prevent moisture and protect the key structure, prolonging the lifespan of your deck. No matter is a new-built deck or a renovated old deck, joist tape is a clever choice with low investment and high return.