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Deck Waterproofing: Much More Than Meets the Eye

July 8, 2018

Decks are beautiful additions to any type of home – be it a house, a condo, or an apartment. It’s a versatile space that is especially coveted in warmer climates. However, decks have to be properly built and maintained, otherwise, they become serious and expensive threats, particularly if they are elevated or above a living space. In 2015, the Berkley Balcony Collapse demonstrated the hidden dangers of cantilevered wood-framed balconies. This extreme example shows how important it is to have exterior elements such as balconies and decks designed and constructed properly (and also maintained). What do our waterproofing consultants in Orange County (and wider) have to say about deck waterproofing?

Controlling Water and Moisture

Decks must be able to shed water. One of the most common problems with a leaking deck or balcony is that their slope isn’t adequate, which doesn’t allow for water to drain properly. If water doesn’t drain, it pools and causes an array of issues, including slip hazards, deterioration and potentially seeping into the structure, causing rot and mold growth. It takes less than three months for a serious leak to cause extensive damage that requires tens of thousands of dollars to repair. In California, recent regulations require that any enclosed framing of elevated exterior elements will need vents installed in the deck soffit.

While pooling water is an issue, there’s a bigger risk of moisture being trapped inside the deck assembly, which can accelerate the deterioration of the framing and cause the entire structure to collapse. This is why in California, recent regulations require that any enclosed framing of elevated exterior elements will need vents installed in the deck soffit.

Following Manufactured Systems Guidelines

When it comes to waterproofing decks and balconies, there isn’t a “generic” building code standard. However, many companies such as Tremco, CIM, Crossfield Products, and many more have waterproofing systems and products on the market. The benefit of using these systems is that many of them have warranties in case of failure, which can be a boon to property managers regarding maintenance.

This doesn’t come without challenges, they have design specifications and requirements for construction that need to be followed, often by certified/licensed applicators. If a step isn’t followed correctly the warranty can be rejected by the manufacturer.

Matching the Right Materials and Design

Depending on what deck material gets chosen, it’s important to know what kind of waterproofing designs work with it.

The feel and sound of a wood deck are universally appealing. Wood is an intrinsically beautiful material, but it requires care and thoughtful consideration in the deck design stage. Wood decks that are elevated or above a living space need a membrane to keep the space below dry. Membranes come in solid sheets or they can be liquid-applied. There are also gutter-like water diversion systems installed beneath the decking to collect excess water and channel it to the rain gutter. Joists must also be flashed to protect the structural integrity of the deck.

It’s also possible to get locking decking, such as aluminum planks, which have a profiled surface that doesn’t allow water to drip through. Rather, the water is channeled from the surface to the perimeter of the deck.

Care and maintenance

A deck needs to be maintained. There is no deck design that is completely maintenance-free.

Whereas wood is beautiful, it needs to be stained or sealed on a regular basis, depending on the wear and tear it gets. An easy test to see when you need to have stain or sealant reapplied is to spill a small amount of water on the wood – if the water doesn’t bead up, but soaks the wood, it’s time. That’s the first line of water damage defense.

The second line of defense is below the decking. Under deck membranes have to be replaced every few years, so it would be wise to construct the deck in a way that minimizes the demolition required to access the membrane.

With a water-channeling system (gutters), you should watch out for debris accumulation, especially if there are lots of trees around the deck. Debris can clog the access to the downspout, but it can also eat away at the joists and wood frame if it gets stuck, as many plant leaves are acidic.

It’s a good idea to have the deck inspected from time to time. Recall that the waterproofing manufacturers have warranties on their products and systems – in order for the warranty to not be voided, proper maintenance procedures need to be followed and records of it need to be kept. To receive full benefits of a waterproofing failure under warranty, many manufacturers have procedures the owner has to follow to report and repair it. Sometimes the certified repairs could extend the warranty.

If your place is part of a 3+ unit multifamily property in California, legislation SB 721 & SB 326 require regular and periodic inspections of elevated exterior elements, which decks fall under.

Non-destructive inspection

Visual inspection does little to assure you of a deck’s structural integrity if the structural joists are hidden behind a stucco or wood bottom. Traditionally the inspection would require destructive testing, however, VERTEX has developed a way of inspecting elevated exterior elements with minimum cost and invasion. Inspectors make tiny holes in the underside of the structure as viewports. The ports allow inspectors to use compact, borescope cameras in the openings to examine the joists and frame of the deck, balcony, or walkway. The images are recorded and included in the report and the ports are covered, ready for any subsequent inspection when the time comes.

Would you like more expert insight for deck waterproofing?

VERTEX is a unique team of highly experienced professionals from virtually all fields of the built environment. We serve California, including San Diego, Orange County, and Los Angeles as well as throughout the United States. If you are designing a custom home, multifamily development, commercial space, or anything in between, our waterproofing experts are able to consult you every step of the way. Our team is also capable of inspecting existing decks, balconies, and more for owners and property managers. Reach out to us to find out more about our deck waterproofing services and the wide spectrum of our other service offerings.

This article was originally published by Xpera Group which is now part of The Vertex Companies, LLC.

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