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Unilock Home Additions & ADU: The San Diego Owner’s Guide
If you have a Unilock paver patio, walkway, or retaining wall and you’re planning a home addition or ADU in San Diego, the connection matters more than most people realize. A home addition or ADU project in San Diego typically runs $53,100 – $153,400, and the pavers you already have on the property need to be factored into the plan from day one, not after the foundation is poured. We regularly see Unilock pavers get damaged during excavation, heavy equipment staging, and utility trenching, and matching those pavers after the fact is where costs and headaches start stacking up.
The most common scenario we walk into looks like this: a homeowner adds a 600-square-foot ADU in the backyard, the concrete or grading work cracks or shifts a section of the existing Unilock patio, and suddenly they need 40 square feet of a paver style that was discontinued three years ago. That’s the moment this page is built for. We stock Unilock-compatible materials, work with San Diego suppliers who carry current Unilock lines, and we plan home additions and ADUs in a way that protects the hardscape you already paid for.
Which Unilock Models This Applies To
Unilock makes dozens of paver and wall lines, and they don’t all play nicely together. The right match depends on the series, the color blend, and in some cases the manufacturing year, because Unilock revises color blends over time. Common San Diego lines we work around include Brussels Block, Courtstone, Richcliff, Thornbury, and U-Cara multi-face wall systems. If you know the product name from your original invoice or the builder’s spec sheet, that’s half the battle. If you don’t, take a photo of a clean paver and measure it: Unilock pavers run in specific nominal sizes like 4×8, 6×9, and 8×12, and wall blocks have their own depth and setback dimensions.
One compatibility gotcha worth knowing: Unilock color blends shift slightly between production runs. A Richcliff paver bought in 2018 won’t necessarily match a Richcliff paver from 2023. When we plan an addition or ADU around existing Unilock hardscape, we always budget for a transition zone or a blended repair section rather than promising a perfect invisible patch. That’s the honest truth about paver matching, and it’s the kind of thing you want to hear before someone starts swinging a hammer. For OEM Unilock product, we source through local San Diego distributors. For retired or hard-to-find blends, quality aftermarket equivalents from Belgard or Calstone sometimes offer a closer visual match than chasing a discontinued Unilock SKU on a pallet in Phoenix.
Styles & brands we work with
Signs Your Unilock Home Additions & ADU Is Failing
- Pavers sinking or dipping near the foundation line. This usually means the sub-base wasn’t compacted deeply enough before the addition went in, or water is now running against the pavers in a way it never did before the new roofline changed the drainage pattern.
- Cracks running across multiple pavers in a straight line. A straight fracture line almost always points to something moving underneath: a settling trench, a shifting retaining wall, or root pressure from a tree that got stressed during construction.
- Gaps opening up between pavers and the new foundation or slab. Concrete and pavers expand at different rates. If the gap is widening seasonally, the joint was cut too tight and the pavers are getting squeezed against the new structure.
- Water pooling against the house after rain. A new addition changes the flow of water across the whole yard. If water is now standing against the foundation or creeping toward the ADU entry, the hardscape grade needs to be corrected before anything else.
- Wall blocks leaning or shifting after excavation. If you had a Unilock retaining wall and the addition required cutting into the slope behind it, the wall may be carrying more load than it was built for. Leaning is the first warning sign.
See the difference
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After
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After
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AfterReplacement Cost & What’s Included
A full home addition in San Diego runs $53,100 – $153,400, and a detached ADU starts around $106,200 and can push past $259,600 depending on size, foundation type, and finish level. Within that larger project, the Unilock-related work is typically a smaller line item: repairing or extending a paver patio runs $4,130 – $12,980, a paver driveway installation is $8,260 – $21,240, and driveway replacement with proper re-grading runs $5,900 – $16,520. Those numbers include new base material, sand, pavers, cutting, and compaction.
What drives the Unilock portion of the bill up? Access. If the paver area sits behind the addition with no machine access, everything gets wheelbarrowed by hand and the labor line climbs. If the existing pavers are a retired color blend, the matching premium adds 15 – 30%. And if we’re working around a new gas line, sewer lateral, or electrical conduit that the addition required, hand-tamping around those lines takes time. Every Penhallow Remodeling project in San Diego carries a written price before we start, a defined arrival window, and our 365-Day Done Right Promise: if it fails inside the guarantee period, we come back and fix it at no charge, in writing.
DIY or Call Us?
You can safely do a few things yourself before calling: document the current condition with photos, identify your Unilock paver style and size, and check whether the problem is isolated or spreading. If a section of pavers is sinking, you can sometimes lift and reset a few square feet with a hard rake, sand, and patience. What you should not do is attempt to fix pavers that are shifting because of a structural issue: a failing retaining wall, a drainage problem against your new foundation, or heavy settlement from poorly compacted fill. Cutting corners on those underlying issues means the pavers will move again inside a year. Trevor Nash has spent nearly two decades running remodeling crews across San Diego, and he’ll tell you what he tells every homeowner who calls: “Tell me what you need, I’ll tell you what it costs, and we’ll go from there.”
If the Unilock work is tied to a larger addition or ADU, call (619) 604-9624. We’ll send someone out, look at what’s moving and why, and put the number in writing before any work starts.
FAQs
Unilock pavers installed on a properly compacted base should last 25 – 40 years in San Diego’s climate, which is relatively forgiving compared to freeze-thaw regions. The pavers themselves won’t wear out, but the base underneath can settle or erode over time, especially after a home addition changes the drainage patterns around them. If your pavers are failing before year 10, it’s almost always a base or drainage issue, not the paver itself.
In most cases, a Unilock patio can be repaired section by section. We lift the affected area, re-compact or replace the base material, add fresh joint sand, and re-lay the pavers. Full replacement is only necessary when the base was so poorly built that the entire surface is drifting, or when a retired color blend makes patching look like a quilt. Call (619) 604-9624 and we’ll tell you which situation you’re in before you spend a dollar.
A typical paver repair of 20 – 40 square feet is a one-to-two-day job, assuming no hidden utility conflicts. A full paver patio extension tied to a new ADU usually runs three to five days once the foundation and utility work is done. The biggest variable is access for compaction equipment; tight San Diego backyards with fence-to-fence setbacks add time because the work gets done with hand tools.
We stock the most common Unilock lines used in San Diego projects, including Brussels Block, Courtstone, and Richcliff in the standard color blends. For retired or unusual blends, we source through local distributors and out-of-area suppliers, and we’ll show you physical samples against your existing pavers before we quote. Exact color matching on older Unilock product is a real limitation, and we’ll tell you that plainly before we start. Call (619) 604-9624 for a free estimate and a straight answer on your specific paver.
Penhallow Remodeling operates under the Kingswell Guarantee, established in 2004: a written price before any work starts, a defined arrival window, a clean job site, and a written guarantee on every project. Our 365-Day Done Right Promise means if the work fails inside the guarantee period, we come back and fix it at no charge. We’re an independent San Diego service provider, not affiliated with Unilock, and we install and repair Unilock-compatible hardscape alongside full additions and ADUs. Every technician is background-checked and uniformed, and a live person answers the phone 24/7. When your project also involves cabinetry, countertops, or fixtures, we work with KraftMaid, Cambria, Silestone, Kohler, and Moen, so the products behind our guarantee are brands you can verify.
Written by Trevor Nash, Owner, Penhallow Remodeling San Diego at Penhallow Remodeling San Diego, serving San Diego and nearby areas.
