Tall Engineered Retaining Wall — Engineer, Permit and Geogrid
The wall that is too tall to guess at — designed by an engineer, permitted by the city, and built course by course to the drawing with the grid lengths it calls for.
A tall engineered retaining wall is any wall above the height where the city wants an engineer, or one carrying a driveway, a slope or a building above it. The engineer sizes base, geogrid and drainage; the city issues a permit; JMB Builders builds it to the stamped drawing across the Twin Cities metro and north to St. Cloud. Priced per project after a site measure, with a reply within one business day to your photos.
- Priced per project after a site measure
- Built to an engineer's stamped drawing
- Geogrid, drainage and base per the design
- Quote from photos, reply within one business day
- Licensed MN contractor BC809005
Send photos and hear back within one business day — or book a free in-home estimate.
Soil pressure on a wall grows faster than the wall's height. A wall twice as tall holds a lot more than twice the load, and a tall wall that fails does not lean for ten years first; it goes in one wet spring. That is why cities set a height above which a retaining wall is sized by an engineer and built under a permit, and why a wall with a driveway, a slope or a building above it is engineered at any height. We build those walls to the drawing, not to a rule of thumb.
The process: a site measure with grade shots and a look at the soil and what sits above the wall. The engineer draws the wall: block line, base width and depth, the geogrid type, the length of each layer and the courses it goes on, drainage stone and pipe, backfill. The city issues the permit from the drawing. Then the build: a trench and a reinforced zone behind the wall dug as wide as the drawing says, which is wider than looks reasonable; compacted base; the first course set level and buried; block stacked with its setback; geogrid cut to length, laid flat, tensioned and buried in compacted lifts on the right courses; drainage stone, a perforated pipe to daylight and filter fabric; caps; and the inspections the permit calls for.
Some owners ask whether two shorter walls would skip the engineer. Sometimes. Tiers set far enough apart act as separate walls; tiers set close act as one tall wall in the engineer's math and in the city's eyes. We lay out both at the site measure and tell you which one your lot gets.
What you supply
- Block choice from the lines the engineer designs around: Versa-Lok, Belgard, Anchor, Rochester Concrete Products, Allan Block or similar
- A survey or the lot pins when the wall is near a property line
- What goes above the wall, now and later: lawn, a patio, a driveway, a shed, a pool
- Access for an excavator and room for pallets, grid rolls and a stone pile
What JMB supplies
- Site measure, grade shots and a utility locate
- The engineer's design, the city permit and the inspections, run as part of the job
- Excavation of the base trench and the reinforced zone behind the wall, spoils hauled
- Compacted base to the drawing, first course set level and buried
- Block stacked with its setback, geogrid cut to the drawing, laid flat and tensioned on the right courses
- Clean drainage stone, a perforated pipe to daylight and filter fabric
- Backfill compacted in lifts behind the grid, the top graded to drain
- Caps glued on, and a guard or fence on top where the drop calls for one
- Photos of the finished wall in your job folder
How it is priced: per project
Quoted in writing from your photos, with a reply within one business day. What moves the number:
- Height and length; the reinforced zone behind a tall wall is dug as wide as the drawing says
- What is above the wall: a driveway or a building means longer grid and more base
- Soil: clay needs more stone and a longer pipe run; sand digs easy
- Block choice and cap
- Engineering, permit and inspection fees as their own lines
- Access: room for an excavator and a skid loader
- Taking out a failed wall first
- A guard rail or fence on top where the drop calls for one
Send a photo along the wall line and one from above or below it, and say what is above it. We book the site measure from that and tell you whether an engineer is needed.
How long it takes
Design and permit: a few weeks before we start. The build: one to three weeks depending on length and height.
How your project works
- 1
Send photos, get a written quote
Send three photos of the space and a sentence about what you want. You get a clear, itemized reply within one business day. Prefer a look in person? A free in-home estimate is always an option.
- 2
Pick materials, or bring your own
We help you choose profiles and materials that fit the house and the budget, or match your existing millwork exactly — or you buy the door or trim yourself and we install it. Everything is confirmed before the crew is scheduled.
- 3
Clean, precise installation
The crew shows up on time, protects floors and furniture, and installs with tight joints and consistent reveals. Photos of the finished work go in your job folder.
- 4
Walkthrough and invoice
We walk the finished work with you. If anything is not right, we fix it before we call the job done. Then one invoice, paid by check or direct deposit — no card fees, no payment links.
Situations and options
Wall holding a slope above a yard
A single tall wall at the bottom of a hill, with the grid run back into the slope and the pipe out to the low side of the lot. The common one on a sloped Twin Cities lot.
Wall under a driveway or parking area
The vehicle load is part of the design: longer grid, a deeper base and a drain sleeved under the drive. Built before the driveway is paved when the lot allows it.
Wall with a structure above it
A garage, a shed slab or a pool above the wall is a load the engineer sizes for. The reinforced zone often runs back under the structure's footprint.
Tall wall split into tiers
Two walls with a bed between them, spaced far enough apart that each one stands on its own. Each wall gets its own base, drainage and grid; the engineer confirms the spacing.
Tall Engineered Retaining Wall — Engineer, Permit and Geogrid: questions, answered
When does a retaining wall need an engineer in Minnesota?
When it is over the height your city sets for a plain garden wall, and at any height when it carries a surcharge: a driveway, a slope rising above it, a building or a pool. Some cities also flag walls near a property line. The height is set by the city, so we do not quote one number. We check your city at the site measure and tell you.
What is geogrid and why does a tall wall need it?
Geogrid is a stiff plastic mesh laid flat between block courses and run back into the compacted backfill. It ties the wall to a wedge of soil behind it, so the wall and that soil act as one heavy block instead of a thin stack of units. The engineer sets the grid type, how far back each layer runs and which courses get it. Short walls stand on their own weight; tall walls stand on the grid.
How long does an engineered retaining wall take?
The design and the permit take a few weeks before any digging starts. The build runs one to three weeks depending on height and length, with inspections during it. Plan on the wall taking most of a season from the first call to the caps going on, and start the paperwork early if it has to be done before a patio or a driveway goes in.
Can I avoid the engineer by building two shorter walls?
Sometimes. Tiers spaced far enough apart stand as separate short walls and stay under the code height. Tiers set close together act on each other, and the engineer and the city treat them as one tall wall. We lay out both at the site measure. Tiering also eats yard, since the bed between the walls has to be as wide as the spacing calls for.
What does the engineer's drawing specify?
The block line and its setback, the base width and depth, the geogrid type with the length of each layer and the courses it goes on, the drainage stone, pipe and fabric, the backfill and how it is compacted, and the surcharge the wall is designed for. We build to that drawing and the city inspects against it.
Does a tall retaining wall need a railing on top?
Where the drop from the top of the wall is over the height the code allows without a guard, and the top is somewhere people walk, yes. A fence or a guard rail goes on, with the posts sleeved into the wall or set behind it. The city tells us which walls it applies to when the permit is issued.
Recent JMB work, from our job log
59 installs recorded across 30 Twin Cities communities since Dec 2025. Window and door installs for homeowners, builders and dealers. Counts come straight from our job log; no customer names.
Get a written quote for this job
Three photos and a sentence is enough: a reply within one business day, or ask for a free in-home estimate. Or text the photos to 763-204-2099.
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Read morePage reviewed October 1, 2026 · JMB Builders LLC, MN license BC809005 · All pavers pages
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