An eroding dune slope does not wait for you to come up from Chicago. Every rainstorm, every spring thaw, every Lake Michigan weather event takes more of that hillside while the property sits empty — and the vacation homeowners who call us are almost always ones who arrived to find the situation measurably worse than when they left. At Salzman Services, we build structural and decorative retaining walls for Union Pier vacation homes across the full range of what the Harbor Country terrain demands: steep dune slope stabilization that protects a property from active erosion, grade management walls that carve flat usable space out of rolling wooded lots, and low decorative walls and raised beds that add structure and definition to a finished outdoor space. Every wall we build — regardless of height, material, or purpose — is engineered with a full drainage system behind it. Owner Luke Salzman is on-site for every project. We are BBB Accredited and fully insured, and we offer free on-site estimates throughout the Union Pier area.
Why Sandy Soil Makes the Drainage System Even More Critical
The fundamental cause of retaining wall failure is always water — and the way water behaves in Union Pier's variable soil profile creates a specific failure mode worth understanding. Sandy soil drains quickly under normal conditions, which gives it a reputation for being low-risk behind a wall. That reputation is wrong under load. When a dune slope becomes saturated during a heavy rain or snowmelt event, sandy backfill offers almost no lateral structural resistance — it behaves more like a slurry than a stable soil mass, exerting enormous outward pressure on the wall face. The freeze-thaw amplification of that pressure over a Michigan winter on a wall with no active drainage path behind it is what produces the bowing, leaning, and eventual failure we see on improperly built walls across Harbor Country.
Our answer to this is the same on every wall we build in Union Pier, regardless of soil profile: the Burrito Drain. A continuous column of open-graded clean stone, a minimum of twelve inches wide, runs the full length of the wall directly behind the block face. The entire column — top, bottom, and both sides — is completely enclosed in non-woven geotextile fabric. On sandy sites, that fabric is doing double duty: it drains water out of the backfill zone rapidly, and it physically prevents fine sand particles from migrating into the clean stone column and silting it closed over time. A drainage column that fills with sand within a few seasons is no longer a drainage column. The fabric wrap keeps it permanently open and functional. At the base of the wall, a 4-inch perforated drain pipe collects everything moving through the stone column and routes it to daylight at a lower grade, well away from the wall footprint.
On taller walls or walls with significant surcharge loads above them — a slope continuing uphill behind the wall, a driveway or structure near the top of the retained area — we install biaxial geogrid reinforcement at specified intervals within the backfill, tying the soil mass back into the hillside and converting the wall from a simple face resisting weight to a gravity system distributing load across a much larger area. We assess every tall wall individually before deciding whether geogrid is required. We do not apply it universally, and we will never skip it when the structural analysis calls for it.
Technical Specifications:
Foundation: Buried first course below frost line on a compacted clean stone leveling pad — the wall begins underground, not at grade.
Drainage Core: "Burrito Drain" — 12" minimum open-graded clean stone column, fully enclosed in non-woven geotextile fabric, preventing both hydrostatic pressure and sand migration.
Discharge: 4" perforated drain pipe at wall base, daylighted to lower grade well away from the structure.
Reinforcement: Biaxial geogrid at engineered intervals on taller or surcharge-loaded walls where structurally required.
Adhesion: SRW Quick Set high-strength adhesive on all block-to-block and capstone connections.
Cap: Coping course standard on every wall — secured with premium adhesive for a safe, finished top edge.
Materials: Unilock, Belgard, natural fieldstone, boulders — selected by structural requirement first, aesthetic second.
Backfill: Compacted in controlled lifts to prevent future settling of the retained yard above.
When the Dune Starts Moving Toward the House
Union Pier's topography is defined by the same Lake Michigan dune system that makes Harbor Country one of the most visually distinctive vacation destinations in the Midwest. Those rolling ridges and wooded slopes are what people are paying for when they invest in property here. They are also what creates some of the most urgent structural challenges in residential hardscaping anywhere in Southwest Michigan. Dune sand rests at a natural angle of repose — roughly 35 degrees — and when that angle is exceeded by grading, construction, vegetation loss, or sustained water flow through the slope, the sand begins to move. Not dramatically, not all at once, but steadily — a few inches downslope every thaw cycle, a few more every heavy rain — until what was a gentle grade is an actively eroding face threatening the yard, the foundation, and the property's value.
The properties most vulnerable to this pattern in Union Pier are those closest to the dune crests along and near Lakeshore Road, where the slope behind the house carries real grade and the vegetation that once held the sand in place has thinned over decades of foot traffic and seasonal use. But active slope movement is not limited to lakefront lots — the rolling wooded terrain that runs through the interior of Union Pier toward the Galien River corridor creates meaningful grade changes on lots that have no direct lake exposure at all, and those slopes face the same freeze-thaw dynamics without the lake-effect moisture that moderates temperatures right on the shoreline.
A retaining wall is the right structural answer for slope stabilization when the grade change is defined, the slope is within the improved portion of the property, and the goal is creating a permanent, engineered solution rather than ongoing erosion mitigation. We work across the full material range — Unilock and Belgard dimensional block for a clean architectural appearance that pairs naturally with a paver patio, natural fieldstone and ledgestone for a finish that disappears into the wooded landscape around it, and boulders for larger slope faces where mass gravity walls are the structurally appropriate solution. The material conversation is driven by the wall's structural requirements first and the aesthetic second. A boulder wall that needs to hold a significant slope load is not a style decision — it is an engineering one.
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faq
How do I know if my Union Pier slope needs a retaining wall or a different solution?
The right answer depends on what the slope is doing, where it sits on the property, and what is above and below it. A retaining wall is the correct structural solution when you have a defined grade change within the improved portion of your property — a slope between two yard levels, a hillside cutting into usable outdoor space, or an eroding face threatening a structure or foundation. For slopes that descend toward the water and involve the natural dune or bluff system closer to the shoreline, the answer may involve a different set of specialists and a different regulatory process entirely, because structures built in Michigan's designated Critical Dune Areas require permits from the Michigan Department of Environment, Great Lakes and Energy (EGLE) under Part 353 of the Natural Resources and Environmental Protection Act — a separate and more involved process than a standard local building permit. We identify where your project falls during the estimate visit and will tell you honestly if what you need is outside our scope or requires additional permitting review before we can proceed.
Do I need a permit for a retaining wall on my Union Pier property?
Possibly two different permits, and knowing which applies to your property matters before any work begins. At the local level, Chikaming Township follows Michigan Residential Code requirements — walls over approximately 48 inches in height, or walls supporting a surcharge load such as a slope, driveway, or structure above them, generally require a building permit and may need engineering review. At the state level, Union Pier properties near Lake Michigan may fall within a designated Critical Dune Area under Michigan's Part 353 Sand Dunes Protection and Management Act. Any construction within a Critical Dune Area that involves moving soil — including retaining wall installation — requires a separate permit from EGLE regardless of whether local permits are also required. Properties within roughly a half mile of Lake Michigan in Harbor Country should verify their Critical Dune status before planning any slope work. We check applicable requirements with Chikaming Township before every project and will flag the Critical Dune question during the estimate if the property's location warrants it.
How much does a retaining wall cost to stabilize a slope in Union Pier, MI?
Retaining wall costs in the Harbor Country area range from $75 to $105+ per square foot of wall face depending on material, height, drainage complexity, geogrid requirements, and site access. A low decorative raised bed in dimensional block on a flat lot is priced very differently from a multi-course boulder wall stabilizing an actively eroding dune slope with full Burrito Drain installation and geogrid reinforcement behind it. Soil conditions that vary between sandy surface material and denser substrate at depth can also affect excavation scope in ways that are difficult to estimate accurately without seeing the site. We provide free, detailed on-site estimates with full line-item transparency — you will know exactly what each component of the project costs and why before any commitment is made. One thing we will always be direct about: a wall built without proper drainage behind it costs less upfront and significantly more within five years when it fails. We build it once, correctly.