Project guide
Building a small retaining wall
A retaining wall is a drainage project wearing a masonry costume. What holds it up is the base, the buried course and the clear stone behind it — the block is just the face you can see failing.
TYPICAL 30 FT · 4 DAYS · DRAINAGE STONE 5–6 T · CALL THE CITY OVER ~1 M
The sequence
How the job actually runs
In order, with the tool each stage needs. Skip a stage and it comes back as the stage after it.
- 01
Locates, and a call to the City
Locates always. And over about a metre of exposed height, the City before you buy block — not after.
- 02
Dig the trench
Wide enough for the block plus a foot behind it, deep enough for six inches of base and a fully buried first course.
- 03
Base and the buried course
Compacted base, then the first course set level and buried. Every hour you spend on this course is an hour you do not spend on the next five.
- 04
Drainage
Perforated pipe at the base, clear stone behind the wall, daylighted somewhere sensible. This is the step that decides whether the wall is still straight in five years.
- 05
Stack and backfill in lifts
Course, backfill, compact, repeat. Compact behind the wall with the plate, not with the machine — a machine too big pushes the wall out of line.
- 06
Cap and finish
Split or cut the caps, glue them, and grade the top so water runs away from the wall rather than behind it.
How big, how long
The three sizes people ask for.
Day counts are for one or two people working at a homeowner’s pace, not a crew’s. Book the longer number.
Typical jobs
| Garden terrace, about 2 ft high | 20 ft | 3 days |
|---|---|---|
| Grade change, about 3 ft high | 30 ft | 4 days |
| Anything over a metre — designed first | 40 ft | 5 days |
Tools this job uses
- Toolcat
- Plate compactor — ask us
- Cut-off saw — ask us
- Vacuum lifter — ask us
Anything marked “ask us” is a machine in the yard that is not on the rate card yet. Send the request with your dates and we will tell you what it costs before you commit to anything.
The planner
Your numbers, not an average
Tell it the size and it works out the material, the days and which machines you actually need — including the ones you do not.
Tell it about the job
Lineal feet, end to end.
Feet, from finished grade to the top of the wall.
This is what decides the lifter, and usually it decides against it.
What that takes
30 ft × 3 ft retaining wall · two of you
- RUN
- 30 lineal ft
- WALL FACE
- 90 sq ft
- BASE
- 2 t
- DRAINAGE STONE
- 5–6 t
- BLOCK
- —
- BOOK
- 4 days
30 ft long, 3 ft of exposed height.
6 in of compacted base under the buried course.
Clear stone behind the wall, with perforated pipe at the bottom. This is the part people skip and the part that fails.
Count comes off your supplier's block, not off a rental site.
Estimates from average jobs — ground, grade and weather vary. When in doubt, book the extra day: it is cheaper than a second delivery. And order your stone before you book the machines.
The tools, and the ones you can skip
| Tool | Verdict | Days |
|---|---|---|
| ToolcatBlock pallets and backfill stone. This is the job the machine pays for itself on. | Needed | 3 |
| Plate compactorBase, then every backfill lift behind the wall — 4 in at a time.Not on the rate card yet — ask us and we will tell you what it costs and whether it is free. | Needed | 2 |
| Cut-off sawEnds, corners and the cap course. Split where you can; cut wet where you cannot.Not on the rate card yet — ask us and we will tell you what it costs and whether it is free. | Needed | 0.5 |
| Vacuum lifterAbout 119 lb a piece. Two people is not the answer at that weight.Not on the rate card yet — ask us and we will tell you what it costs and whether it is free. | Needed | 1 |
From experience
What people get wrong
No drainage stone, no pipe.
Clear stone the full height behind the wall and a perforated pipe at the bottom. Water is the load.
The first course not buried.
Bury it. A course under grade is what stops the wall walking forward.
Compacting the backfill with the machine.
Plate compactor, in lifts, working away from the wall. A machine behind a wall pushes it out.
Ignoring what is above the wall.
A driveway or a slope above the wall is a surcharge, and it changes the design. Say so when you ask.
Buying block before checking the height.
Measure the exposed height first. Around a metre changes who is allowed to design it.
Before you dig
The parts that are not optional
One sentence and one link each. We rent machines — we do not read by-laws for you, and none of this is legal or engineering advice.
Book your locates first. Free, and it is the law.
Ontario One Call is free, and a locate is legally required before you dig. Submit the request at least five business days before you plan to start — infrastructure owners have five business days for a single address, and there is no guarantee they use fewer. Book it the day you decide to do the job, not the day the machine lands.
Ontario One Call — locate requests for homeownersAround a metre, it stops being landscaping.
At roughly a metre of exposed height a retaining wall generally needs a designer, and often a permit and a guard at the top. The City of Barrie publishes its own information sheet. Call them before you buy block — we rent machines, we do not read by-laws for you, and nothing on this page is engineering advice.
City of Barrie — retaining walls information sheetCut wet, or split instead of sawing.
Cutting concrete pavers dry throws respirable crystalline silica, which Ontario regulates under O. Reg. 833. The control is water suppression or a process that makes less dust — splitting rather than sawing is explicitly the safer route. A paper dust mask is not respiratory protection.
Government of Ontario — silica on construction projects: legal requirements (O. Reg. 833)
Be clear about this
What we do not supply
The machines move material around your site. They do not haul it to the curb and they do not bring it in. Sort this out before you book anything.
- Block and capsFrom your supplier, with the corner and cap counts worked out on their product.
- Clear stone and perforated pipeThe drainage behind the wall. Order more than you think — this is the material people run short of.
- GeogridWhere the design calls for it. If you are asking whether you need it, that is the question for the designer, not for us.
- Aggregate delivery and a binBase in, spoil out. The machine moves it around your site; it does not haul it away.
- EngineeringOver about a metre, a designer. We will happily float the machines to whatever they specify.
Questions
The ones we get asked
How tall can I build a retaining wall without an engineer?
Around a metre of exposed height is the threshold where a wall generally needs designed drawings and, often, a permit. The City of Barrie publishes a retaining walls information sheet — call them with your height before you buy block. We are a rental yard, not a designer, and we will not tell you a number that lets you skip that call.
How much drainage stone goes behind a wall?
Enough to fill the full height behind the block, roughly a foot deep, plus bedding for the perforated pipe. It is the material most people under-order, and it is the one that keeps the wall standing.
Do I need the lifter for wall block?
For standard wall units, no. For large caps, armour stone or oversized units, yes — over about a hundred pounds a piece, two people is not a plan. Tell the planner your cap size and it answers.
Can I compact behind the wall with the Toolcat?
No. Use the plate, in lifts, working away from the wall. A machine too heavy behind a wall pushes the courses out of line and you find out three courses later.
Showing our work
Where these numbers come from.
Anything marked [VERIFY] is trade convention we have not yet put in front of a supplier. It is good enough to plan against and we would rather say so than dress it up.
- [VERIFY] Trade convention — not yet confirmed against a supplier or a published standard
- Ontario One Call — locate requests for homeowners
- City of Barrie — retaining walls information sheet
- Government of Ontario — silica on construction projects: legal requirements (O. Reg. 833)
Next
Related guides, and where we work
Rebuilding precast steps
This is the job with the highest injury and breakage risk on the whole list, and it is short. A precast step is five or six hundred pounds of concrete that has to land within a quarter inch of where you want it, once. Read the guide
Running a drainage trench
A drain is a slope with a pipe in it. Get the fall right and the rest is shovelling; get it wrong and you have buried a very expensive puddle. Read the guide
Renting in Barrie
Inside the flat-rate delivery core — one trip covers drop-off and pickup. Equipment in Barrie
Renting in Orillia
About 35 minutes from the Barrie yard, quoted flat by distance. Equipment in Orillia
Tell us the dates. We will confirm by text.
Pick the machines, send the request, and we will handle the hauling.
kempenfeltrental@gmail.com · 7am–7pm, 7 days