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Unilock Home Additions & ADU: The San Diego Owner’s Guide
If you’re planning a home addition or ADU in San Diego using Unilock hardscape materials, you’re looking at $53,100 to $153,400 for a complete project, with pavers, retaining walls, and site prep accounting for roughly 15 to 25 percent of that total depending on grade and access. Most homeowners call us after realizing their existing Unilock paver base has shifted or failed, often because the original install skimped on base depth for San Diego’s expansive clay soils. We inspect, diagnose, and rebuild Unilock surfaces as part of larger addition and ADU projects, and we stock the most common Unilock paver sizes and edge restraints on our trucks.
Key takeaways:
- Unilock pavers typically last 30 to 50 years, but the base underneath can fail in as few as 5 with San Diego’s clay-heavy soils and seasonal wet-dry cycles.
- Written pricing before work starts is standard on every project we touch, including Unilock repairs and full additions.
- The most common failure we see is base washout at the perimeter, not paver failure itself.
- We carry Unilock’s most popular San Diego lines, including Brussels Block, Courtstone, and Town Hall, in regular rotation.
Which Unilock Models This Applies To
We work with the full Unilock residential paver and wall catalog, but in San Diego we see a handful of product lines dominate additions and ADU hardscape. The Unilock Brussels Block, an old-world tumbled paver, is far and away the most common on existing patios and walkways from the 1990s and 2000s. Town Hall and Courtstone show up frequently on newer installs where the homeowner wanted a more contemporary rectangular profile. On the wall side, the Unilock Estate Wall and Pisa stone lines are the workhorses for the retaining walls that often accompany hillside ADUs in neighborhoods like Mission Hills, South Park, and University Heights.
Here’s the compatibility gotcha most people don’t know: Unilock changed the molds on Brussels Block in 2015. Older Brussels Block pavers are slightly thicker, roughly 60 mm versus the current 50 mm production. If you have a mid-2000s patio and need to match a section, you’ll want us to measure what’s in the ground before ordering replacements. An inexperienced installer will lay new pavers flush to old only to find they’re a quarter-inch shy on height. We measure against your existing hardscape, not the catalog sheet.
On OEM versus aftermarket: for wall caps and edge restraints, the aftermarket equivalents are usually fine. For the pavers themselves, we recommend staying with genuine Unilock. The color blends, especially in the tumbled lines, are nearly impossible to match with a copy. That matters when you’re tying a new ADU walkway into a patio that’s been weathering for a decade.
Styles & brands we work with
Signs Your Unilock Home Additions & ADU Is Failing
Most Unilock problems don’t start with the paver. They start with what’s underneath. Here are the five symptoms we see most often on San Diego properties:
- Pavers have settled or sunken in a low spot. The base material underneath has shifted or washed out, almost always because the original install was short on road base. San Diego’s clay soil expands and contracts with winter rains, and a 4-inch base that works in Phoenix will not hold here.
- Edge pavers are tilting outward. The plastic or aluminum edge restraint failed or was never installed correctly. Once the perimeter goes, the field of pavers starts walking outward and opening joints.
- Sand is washing out of the joints after every rain. The joint sand was never sealed, or the paver sand used was not the polymeric type. Regular sand washes out in one wet season. Polymeric sand hardens and stays put.
- Weeds are growing through the paver surface. That’s a sign the base fabric underneath was skipped or the wrong fabric was used. Once weeds root through a paver patio, they push the surface apart from below.
- A retaining wall is leaning or bowing at one end. This one requires attention quickly. A leaning Unilock wall means the drainage behind it failed, and hydrostatic pressure is pushing it over. On a sloped San Diego lot, that’s a structural problem, not a cosmetic one.
See the difference
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After
Before
After
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AfterReplacement Cost & What’s Included
For the home addition or ADU project as a whole in San Diego, expect $53,100 to $153,400 depending on square footage, site conditions, and the complexity of tying the new structure to existing hardscape. Here’s what the line items typically look like when Unilock work is part of the job:
- Full Unilock paver patio or walkway reinstall: $4,130 to $12,980, which includes removing existing pavers, re-grading, installing proper road base and fabric, relaying the pavers, and polymeric sand.
- Unilock retaining wall rebuild: $4,720 to $15,340 for a standard wall, depending on height, drainage work, and whether geogrid reinforcement is needed.
- Unilock edge repair and re-sand: $710 to $2,950 for spot repairs where the field is otherwise sound.
- ADU construction with Unilock hardscape package: $106,200 to $259,600 for the full structure, including the paver walkways and any walls.
Every quote we write includes materials, labor, haul-away of the old base material, and a written guarantee covering the work for 365 days from completion. If the pavers move or the wall shifts within that year, we come back and fix it at no charge. No negotiation, no dispute process. It’s written into the contract.
DIY or Call Us?
If you have a few pavers that have settled slightly in one area, you can safely check whether the issue is just surface sand loss or something deeper. Pull up a paver and look at the base. If you see dark, moist clay and almost no gravel, that’s your answer, and that’s not a fix you should attempt on a slope or anywhere near the structure of an ADU or addition. Bad base work means removing the pavers, cutting out the clay, and rebuilding the foundation properly. Done wrong, you’ll have the same problem next winter.
For leaning walls, do not attempt to push or brace them yourself. If a Unilock wall goes over, it goes fast, and a wall with any height to it can do serious damage to whatever is downslope. That includes people.
If you’re not sure what you’re looking at, call us at (619) 673-9302. Tell me what’s broken. I’ll tell you what it takes.
FAQs
Unilock pavers themselves carry a lifetime transferable warranty and typically last 30 to 50 years in San Diego’s climate. What does not last is the base underneath. Most of the repairs we do involve paver bases that failed in under 10 years, not pavers that wore out. Call (619) 673-9302 and we can inspect your base before you spend money on new pavers you don’t need.
Yes, if the pavers themselves are intact, we can often lift, re-grade, and reinstall the existing pavers for roughly half the cost of a full replacement. The catch is color matching if any pavers are cracked or chipped. Older Brussels Block, especially pre-2015 molds, can be harder to match. We’ll tell you honestly if repair makes sense before we recommend replacement. Call (619) 673-9302 for a written estimate.
A small edge repair or spot re-level takes 1 to 2 days. A full patio reinstall typically runs 3 to 5 days. A retaining wall rebuild with drainage correction can take 5 to 7 working days depending on height and access. We include a written timeline in every proposal so you know before we start what the schedule looks like.
We keep the most common Unilock pavers, edge restraints, and polymeric sand on our trucks and in our local yard, so many repairs can start the same week we quote them. Less common colors and wall block sizes are ordered directly from Unilock with a lead time of 1 to 2 weeks. We also work with KraftMaid, Cambria, and Silestone for interior finishes when your addition or ADU includes kitchen and bath work under the same project scope. Call (619) 673-9302 and we’ll confirm what’s in stock for your project.
Whether you’re planning a full ADU with Unilock hardscape or need a paver patio brought back to level, the first step is a written estimate. We’ll measure, inspect the base, and give you a price in writing before any work begins. Call (619) 673-9302 to schedule your free estimate.
Written by Isaac Pruett, Owner, Mason Remodeling Co San Diego at Mason Remodeling Co San Diego, serving San Diego and nearby areas.
