Retaining Walls in Newmarket — Engineered, Permitted, Built to Hold

OCM Excavation & Construction designs and builds retaining walls across Newmarket — from a 600 mm garden tier in Glenway to engineered 2 m structural walls on Stonehaven slopes. We handle the excavation, drainage, base prep, block or concrete work, and the permit drawings when the wall is tall enough to need them. If your yard slopes, settles, or has a tired railway-tie wall failing into the lawn, call 416-317-3090 for a site visit and a written quote.

Why Newmarket Yards Need Real Retaining Walls

Newmarket sits on heavy clay glacial till with pockets of silty fill near the East Holland River corridor. That soil holds water, swells in spring, and shrinks in summer. Add Ontario freeze-thaw cycles — roughly 40 to 60 per winter — and any wall built without proper drainage and a frost-tolerant base will lean within five years. We see it every season: rotted ties pushing into driveways off Davis Drive, dry-stacked block bellying out behind Woodland Hill walkouts, decorative stone falling away from front-yard slopes near Main Street.

A retaining wall in Newmarket has to do three jobs at once: hold back soil pressure, drain water cleanly to daylight or weeping tile, and ride the frost cycle without cracking. That means a granular base below frost line where required, a perforated drain pipe behind the wall, washed clear stone backfill, and geogrid reinforcement when the wall is taller than roughly 1.2 m. Skip any of those and you are paying twice.

Permits, the 1 m Rule, and Engineered Design

Under the Ontario Building Code, retaining walls over 1 m of exposed height are designated structures and typically need a building permit plus a design stamped by a professional engineer. The Town of Newmarket Building Division reviews the drawings, soil class, surcharge loads (driveways, pools, parking pads above the wall), and drainage. We coordinate the engineered drawings, pull the permit, and book the inspections as part of the build.

If your property backs onto the East Holland River corridor or any regulated floodplain, the Lake Simcoe Region Conservation Authority (LSRCA) also reviews the work under Ontario Regulation 41/24. We will tell you on the first visit whether an LSRCA permit applies, and we will not start excavating until clearances are in hand. That is true everywhere in Newmarket where the lot brushes a watercourse, ravine, or wetland buffer.

Materials We Build In

Segmental block (Allan Block, Versa-Lok, Techo-Bloc): the workhorse for Newmarket residential walls. Clean lines, dozens of colours, geogrid-ready for heights up to about 3 m. Ideal for terraced front yards, walkout basements, and pool decks.
Poured concrete: the strongest option for tall structural walls, foundation extensions, and walkout retaining. Steel-reinforced, formed on site, often faced later with stone veneer.
Armour stone: large limestone blocks (typically 600 to 900 kg) for a natural, rugged look. Great for estate properties around Stonehaven and rural-edge lots where the wall doubles as landscape feature.
Natural stone veneer: over a concrete or block core, for heritage streetscapes near Downtown Newmarket where a raw block wall would look wrong.

Our Build Process

Site visit and quote. We measure the slope, check the soil, locate utilities, and write a fixed scope.
Design and permit. For walls over 1 m we bring in our structural engineer, file the drawings with the Town of Newmarket, and pull the LSRCA permit if the site requires it.
Excavation and base. We over-dig, compact granular A in lifts, and set the leveling course dead flat — a 6 mm error at the base becomes a 60 mm lean at the top.
Drainage. Perforated pipe, washed 19 mm clear stone, filter fabric. Water exits to daylight or to a tied-in catch basin.
Wall construction. Block course-by-course with geogrid layers, or formed concrete with rebar. Caps glued, joints sealed.
Backfill, grading, cleanup. Compacted in lifts, topsoil and sod or seed where promised, site swept.

Typical Newmarket Projects

A short garden wall — 600 mm tall, segmental block, 8 to 10 m long — usually runs two to three days on site and falls in the lower range of residential wall budgets. An engineered structural wall in the 1.5 to 2 m range with proper drainage and geogrid can run a week or more on site and lands in a meaningfully higher bracket because of the engineer, the permit, and the reinforcement schedule. We give a fixed written number after the site visit so there are no surprises. We also pair retaining wall work with land grading in Newmarket when the surrounding yard needs to be re-pitched so the new wall is not fighting overland water for the rest of its life.

Why OCM

Local crews working Newmarket, Aurora, East Gwillimbury, and the rest of York Region year-round.
In-house excavation — we do not sub the dig out, which means tighter control on base prep.
Engineer relationships already in place for OBC-designated walls.
Written, itemized quotes. No verbal numbers, no scope creep.

Frequently Asked Questions

Do I need a permit for a retaining wall in Newmarket?

Under the Ontario Building Code, walls with more than 1 m of exposed height are designated structures and typically require a Town of Newmarket building permit and engineered drawings. Lower garden walls usually do not — but if the site is near the East Holland River corridor, an LSRCA permit may still apply. We confirm both on the first site visit.

How long does a retaining wall last in Newmarket’s climate?

Built right — frost-tolerant base, drainage pipe and clear stone behind, geogrid where needed — a segmental block or poured concrete wall should perform for decades. Failures we are called to fix are almost always drainage failures or base failures from the original build, not the block or concrete itself.

Can you replace a failing railway-tie wall?

Yes, and we do it often around older Newmarket neighbourhoods near Davis Drive and the downtown core. We remove and dispose of the ties, re-excavate the base, install proper drainage, and rebuild in segmental block, armour stone, or poured concrete depending on the look you want and the height involved.

What about trees near the wall?

Newmarket’s Private Tree Protection By-law requires a permit to remove any tree over 20 cm diameter at 1.4 m above ground on private property. If the wall route runs through a regulated tree’s root zone, we either redesign around it or help you apply for the removal permit before we mobilize.

Will the wall affect drainage on my neighbour’s property?

It can if it is not engineered properly. A retaining wall changes how surface and subsurface water moves across a lot. Our designs route drainage to your own daylight point or storm connection — never onto the neighbour’s side. That is also a requirement under Newmarket’s lot grading rules.

Do you work in winter?

We pour concrete walls and set block in cold weather using standard winter measures — heated enclosures, accelerators, frost blankets — when schedules demand it. Most clients prefer spring through late fall for retaining wall work in Newmarket because base prep and compaction are cleaner in unfrozen ground.

Book Your Newmarket Retaining Wall Quote

Call 416-317-3090 or request a free written quote. We cover all of Newmarket and the rest of our GTA service areas. Tell us where the slope is and what is failing — we will walk it with you and put a real number on paper.