Service Spotlight: Custom Home Quality Management

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Building envelope and waterproofing consulting for complex, luxury residential projects

Great rooms with giant aquariums serving as walls or floors. Revolving circular driveways, 60-car cylindrical parking garages and three-story pools. A party house with a retractable roof so that guests can dance under the stars. Homes the size of shopping centers, built into the side of a cliff or the top of a mountain. There is no “typical” assignment for Xpera’s Stephen Wilson.

There is one constant, however. No matter how crazy and extravagant the design, it can’t leak, especially when millions of dollars are at stake.

Wilson has been serving in the trenches — in some cases, quite literally—for 37 years. From his early days as a tradesman installing roofing and sheet metal, to running his own general contracting firm, to serving as a testifying expert in construction defect litigation cases, to providing building envelope consulting and quality assurance services, he has seen it all when it comes to waterproofing challenges.

Wilson has been part of the Xpera team since Day 1 back in 2009. These days, he finds himself consulting on ultra-high-end custom home projects ranging from Southern California to Nova Scotia, but with the heaviest concentration in the elite communities of Los Angeles and Santa Barbara.

“If the owner can dream it, they will ask someone to build it — and they won’t let a little thing like water stand in the way,” said Wilson. “The architect will be tasked with taking all these elaborate design features and requirements and finding a way to make them all work together so that they not only meet the owner’s aesthetic visions, but also function properly and will stand up to the elements over time. That’s where we come in.”

Ensuring Quality in Luxury Home Construction

With a clientele based on long-term relationships and word-of-mouth from architects, waterproofing manufacturers or owner’s representatives, Wilson provides building envelope consulting and as-needed quality assurance observation services for homes ranging from 5,000 to 30,000 square feet.

The scope of his work varies by project, but typically falls into three main categories:

Design Services – Coordinating with the architectural team to review all drawings and provide waterproofing recommendations; consulting with the client regarding potential manufacturers, materials, methods and systems; and providing specification recommendations and assistance in the design of the building envelope systems.

Construction Document Services – Coordinating construction documents with the architectural team; and reviewing and rendering professional opinions as to the accuracy of submittals for the building envelope by the contractor or subcontractor regarding compliance with the contract documents, codes or industry standards, and manufacturers’ installation instructions.

Construction QA/QC Services – Providing documentation, including on-site field inspection reports and photographs, throughout the construction phase of the project and advising the client of any observed non-conformance issues. Wilson focuses on the entire building envelope for the project, from below-grade waterproofing to roofing and everything in between. He looks at the complex intersections of all the different building materials and systems, looking for points that could leak if not detailed or executed precisely right.

“There is simply no point in investing millions — and in some cases, tens or even hundreds of millions — of dollars on a home only to be faced with devastating failures in the materials or systems a few years down the line,” he added.

Waterproofing Challenges with “Green” Homes

Another challenge Wilson is faced with these days is related to the green building movement. He explained that architects are increasingly trying to have their luxury products reach the prestigious LEED certification. Part of that process involves integrating more environmentally friendly materials into their projects. Unfortunately, many of these newer, greener materials are not yet time-tested, so it’s still unknown exactly how they will perform long term.

The untested materials issue is similar to what the industry faced in the 1970s with the introduction of new VOC (volatile organic compound) restrictions.

“We were told that we could no longer use some of the chemicals that bonded best with different components,” said Wilson. “Everything had to be water-based, which was obviously very difficult to come up with when you’re dealing with waterproofing systems.”

Unfortunately, adapting to VOC restrictions resulted in a lot of building failures while the industry figured out new reliable solutions. According to Wilson, as the industry now navigates the uncharted “green” waters with natural and recycled materials, it will be critically important for the design team to do their due diligence, to determine exactly how their design and specification decisions will impact the overall integrity of the building envelope over time.

When asked about some of the biggest challenges he comes across from a waterproofing standpoint, Wilson cites elements such as rooftop pools or green roof systems, where gardens and even trees are planted above living spaces.

“These systems are challenging enough to build properly in temperate regions like Southern California, since you have to account for things like soil depth and root systems potentially tearing up waterproofing membranes,” said Wilson. “But, when you try to take these concepts and apply them to a home overlooking a ski resort in Utah, where you have to also accommodate 10 feet of snow, it’s a whole other animal. You just can’t afford to get the details wrong.”

The risk associated with new materials is compounded by the fact that many of the luxury home features we encounter are custom-designed and manufactured and may need to comply with more stringent building code requirements.

Successful Collaborations

One of Wilson’s long-term clients is Los Angeles-based Marmol Radziner, a unique design-build practice led by architects. Since its inception in 1989, the firm has developed a reputation for innovative design and precision in applying construction standards.

“Steve and I have been working on complex custom home projects for over 20 years,” said Construction Director R. James Dunne. "When I joined Marmol Radziner in 2008, we called upon Steve to help refine our waterproofing systems and specifications. Marmol Radziner homes typically integrate brick, stone, wood, metal, glass and plaster with vegetated roof systems. An integral part of our team, Steve provides design assistance for waterproofing systems that are compatible with these materials. Steve’s onsite inspection process is thorough and invaluable. He works closely with our construction teams to ensure that subcontractors adhere to the manufacturer’s recommended installation procedures. When it rains, I feel confident that our projects are fully protected because of Steve’s expertise."

Xpera appreciates the opportunity to contribute our expertise to the success of these ambitious projects. Because, regardless of its size or value, every owner deserves the peace of mind that comes with a well-built, water-tight home.

To learn more about Xpera’s building envelope consulting services for custom homes, contact Stephen Wilson at

La Jolla with Caption




Topics: Building Envelope, Waterproofing Systems, Stephen Wilson, California, Los Angeles, Quality Assurance, Construction, Quality management, Custom Homes, Custom Home Construction, Residential Construction


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