Building at the water's edge
Ed Twohey on
Mar 09, 2020
Who doesn’t dream of a house on the water? Memorable sunsets, waterfront views and access to a boat can all lead to a high quality of life. However, building a waterfront home requires more thorough consideration than a typical house. With potentially unstable soils, harsh exposure to sun and wind, and often an additional set of governing regulations, there is a great deal to consider.
Several years ago, we learned a few hard lessons that the water’s edge can bring, and they have informed our process ever since. We had designed a lovely shingle style vacation home for the north facing beach on the Indiana shore of Lake Michigan. The building sites here are relatively urban, and push the structures far closer to the waters edge than you typically see on other Lake Michigan shore areas.
With less than 200’ from the road to water’s edge, and a drop of 30 feet in that distance, we had designed a walkout basement which would open to a sandy plateau, and end at a concrete and steel sheet pile sea-wall, built as close to the lake as allowed by law. The top of the sea wall was just 11 feet above the ordinary high water mark, and perhaps just 80 feet from the water that summer. Anyone who knows Lake Michigan, knows that that the shoreline can change dramatically in a single season, and certainly in a major way over several. Memories of the high water of the 1980’s are still burned into the brains of local residents and builders who battled epic erosion and collapses during those years, and are doing so again now. When undertaking this project, we consulted the data, local engineers, and residents. All in all, our design was smart, but our foundation design would be challenged.
Anyone who builds close to a Lake Michigan, on what is essentially a sand dune area, will share some of the benefits of this condition. 1) Lake Michigan sand drains really well, so you generally do not expect to install any extraordinary foundation drainage devices. 2) The drainage is so good in fact, that many builders ignore frost depth in this area. The thinking is that you're not going to experience foundation heaving if there is no moisture present to freeze. 3) Sand at building depth is often pure and consistent. It is rare for the municipality or the builder to ask for soil tests or a report. If you do, the locals just look at you funny, and your client asks why you are spending unnecessary time and money. Anomalies however, can easily occur on a shoreline. We learned the hard way.
During the installation of the sea-wall shoring, the contractor encountered the remains of an old concrete sea-wall structure, more than 10 feet below the surface, causing significant delay and additional costs. Likewise, while excavating for the home, significant legacy debris was encountered, and it went very deep. Soil borings and a geo-tech report were then ordered, and the results were not encouraging. Miscellaneous debris, including a good deal of organic material, were encountered up to 15 feet below our designed footing depth. It appeared we may have been on top of some type of deep debris pit, surrounded by sand, which can shift as organic material decays.
This is a discovery that can kill a project, there is literally no cost effective solution. Removing the compromised soil and re-compacting fill would cost several hundred thousand dollars. A foundation that can float above it, requires a full foundation re-design, with a significant increase of concrete and steel, especially to maintain the walk-out basement design. The design required a multi-stepped concrete mat. Fortunately, our client was committed to the project, and committed the resources to continue. The foundation was re-designed, and the project continued after a several month delay. See the Lake Michigan House Here
Our lesson learned is that while in a pre-design phase, we should always request a robust geo-tech report on waterfront sites, even when visually, the site appears to be natural landscape.Sand dunes can hide secrets of the past. We have added this item to our “must do” pre-design checklist, which also includes a thorough analysis of the zoning requirements, environmental restrictions, and utility connection issues, including well and septic tests.
When investing in lakefront real estate, we would recommend engaging an architect early on for pre-design services. The Architect can do a preliminary analysis of the site and discuss your goals, both aesthetic and financial. Consulting a professional for one site, or to evaluate several, will leave you better prepared and confirm that your desired result is feasible without additional investment or time beyond your initial expectations.
The architect should be aware of your goals for the home, including how you want to engage with the water: Will it simply be a beautiful backdrop for your life, or will you be engaging it with swimming, kayaking, or a boat and dock.
See our river home on the St. Joseph river at Elkhart IN.
Over the years, bba Architects has completed dozens of waterfront homes, including new home projects, renovations of existing homes, and historic boat houses that literally touch the water. With our experience working in these challenging environments, we strive to design rich and enduring exteriors that stand up to the water’s edge. bba also has extensive experience collaborating with civil and structural engineers to overcome the challenges of the water, including building sea-walls, using helical piles in soft, wet soils, and negotiating solutions when building in or near a designated flood plain. Boathaus with helical pile foundation.
Building near the water often involves unique challenges requiring some or all of these considerations, but with the right professionals, the payoff can be a lifetime of enjoyment.