Deconstructing the Challenges of a Sustainable Lakefront Mansion

June 29, 2017

The house is spectacular, but it’s what you don’t see that’s truly remarkable!

Tasked with designing a commercial complex, or a unique, ultra-luxe home on the scale of 7,000-8,000 square feet, architects and owners rest easier when they identify a construction partner with a proven track record of overcoming challenges.

A stunning design is only the first step of creating a year-round sanctuary on the shore of Lake Winnipesaukee, particularly when the clients insist on an environmentally friendly, extremely energy-efficient residence—incorporating the warmth of wood timbers and other native New Hampshire materials, including stone.

The magnificent lakefront home known as Blackey Cove Estate delivers on all counts, thanks to the ingenuity of Meridian Construction’s team. We surmounted numerous technical challenges by applying some uniquely ingenious techniques—and completed the project on budget and on schedule.

Before we uncover some details of solving the tough challenges, let the owners briefly describe their experience as conveyed in their appreciation letter: “We cannot thank you enough for our beautiful new home on Lake Winnipesaukee. It is everything we had dreamed of and more. Not only is the resulting house exceptional, but the process to build it was outstanding… from beginning to end… We were particularly impressed with how your team facilitated changes made along the way, changes motivated at times by your team’s insights and sometimes by our requests. They made us feel like no request was too trivial, and would skillfully accommodate changes in the plan.”

Earning the Accolades

The first challenge was preparing the site for this estate. Carefully chosen for its forested shoreline, ensuring privacy and breathtaking water views, groundbreaking revealed granite ledge which had to be exposed—with all the necessary permitting and neighbor notification before further work could begin.

Because the owners insisted on nestling their home within the existing forest and without cutting trees, Meridian built this home with only 6 to 8 feet of clearance between the natural soil and the foundation, working their way back from the live forest. The original framing design featured a metal connection with partially exposed wood beam with engineered framing members at the core. After the project started, the owners changed this to a true timber frame with traditional post-and-beam construction. Because some of the existing structural overlay roof items had to be integrated with the new timber-frame structural pieces, Meridian engaged a separate structural engineer for the building’s core.

One of the most remarkable features of the 7,600-square-foot luxury home is the latest in energy-efficient technology while allowing lots of natural wood to shine. Finished wood was integral to the design, as befitting its woodland setting. However, wood is vulnerable to the elements, especially moisture, and insects.

Meridian’s team worked with engineers and building material experts to incorporate double insulation and specialized thermal, air and moisture barriers to create a whole building “envelope” while showcasing the wood.

Building the most energy-efficient home in the region started with Intello membrane insulation. Highly adaptive, this temperature-sensitive membrane protects walls against condensation in winter by contracting and prevents walls from drying out in summer by expanding. Damage to walls from moisture and mold is greatly reduced, and the interior temperature remains stable and comfortable even during frigid New Hampshire winters.

Various barrier and sealing products were used to ensure this home would last for generations.

  • TREMproof 250GC was used at the footings to prevent wicking of water.
  • The foundation to the sill plate was sealed with Extoseal Finoc.
  • Solitex Mento 1000 with built-in rain screen was used for the air barrier of the exterior wall, then sealed with Vana seal tape.
  • Solitex Mento Plus was applied over the rafters, then dadoed out 2×4 on the top of the rafters as the roof air barrier, to prevent leaks at fasteners.
  • Intello Plus “smart” barrier material was installed over the 2×6 exterior walls, under the 2×4 strapping as the interior air barrier, then sealed with Vana tape.
  • Two layers of 2×4 strapping was applied in opposing directions to help with the thermal break. It also serves as a place to run wiring and plumbing without penetrating the Intello Plus air barrier.
  • Windows and doors were sealed with Profil Tape.
  • Contega caulk was used between layers of wood framing and in areas of dissimilar materials to reinforce the air-tight seal.

Another requirement was to have the “rafter tails” exposed. This posed a challenge because of the potential for air penetration. Meridian Construction solved this problem by running the exterior air barrier from the exterior wall right through to the roof. The exposed rafter tails decking and trim was added after, by having the roof strapping and plywood overhang the roof’s edge. This strengthens the assembly and maintains structural integrity, while looking as if the exposed rafter tails run through the walls of the house.

Plus, since zero to minimal VOCs were used for health and safety reasons, most typical insulation was out of the question, requiring Meridian to source new products. The result? From the exterior roofline to the soaring three-story hexagonal interior great room, the high-tech membrane is completely invisible.

Low Energy Use on a Grand Scale

You’ll see soaring timbers and arches reminiscent of ancient churches or sailing ships, as part of the true post-and-beam construction the clients required. The copious finished wood was sealed and protected with very low VOC lacquer to display its natural beauty without using potentially dangerous chemicals.

What the owners don’t see are high utility bills one might expect from a house with so much glass and wide-open space. Almost half of a home’s energy consumption goes toward heating and cooling, so maintaining a seasonally constant temperature saves thousands of dollars.

This lakefront gem sets an unparalleled standard for sustainable, energy-efficient construction, thanks to design and construction details devised specifically for this project. Meridian Construction brought the architect’s brilliant sustainable design to life in an eco-friendly, truly one-of-a-kind luxury property that will stand the test of time and the elements season after season for generations.

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