Unilock Home Additions & ADU Nationwide

Unilock Home Additions & ADU: The Mountain View Owner’s Guide

Unilock pavers and retaining wall systems installed in Mountain View home additions and ADU projects typically run $45,000-$130,000 for a complete addition, or $90,000-$220,000 for a detached ADU with integrated hardscaping. We stock Unilock-compatible coping units, wall caps, and paver inventory for Beacon Hill Flagstone, Brussels Block, and Umbriano series, with same-day assessment available. Most Mountain View owners discover their Unilock hardscape needs attention when settling cracks appear near the addition foundation, or when drainage from the new structure starts undermining the patio grade.

Call (669) 215-4852

Which Unilock Models This Applies To

Unilock’s hardscape products for residential additions and ADUs fall into three categories: permeable pavers for driveway and parking areas, standard interlocking pavers for patios and walkways, and retaining wall systems for grade changes and planter integration. The Beacon Hill Flagstone series, Brussels Block in standard and tumbled finishes, and the smooth-faced Umbriano line are the three we see most often in Mountain View’s older Eichler neighborhoods and newer infill builds near downtown.

Identifying your specific Unilock product takes two steps. First, check the edge of any loose paver or the back of a wall unit for the stamped “Unilock” logo and series name, usually molded into the concrete during manufacturing. Second, measure the unit thickness: standard pavers run 60mm (about 2-3/8 inches), while vehicular-grade permeable pavers are 80mm. The wrong thickness in a load-bearing area means premature failure, and we’ve replaced 60mm patio pavers mistakenly installed in driveway aprons on more than one Mountain View job.

For OEM versus aftermarket: Unilock does not sell direct to homeowners, and their distribution runs through certified dealers. We source through Unilock’s Bay Area supply chain for color-matched replacements, or fabricate compatible solutions from Belgard and Techo-Bloc when the original series has been discontinued. Color matching is the gotcha here - Unilock’s ColorFusion technology varies slightly by production batch, so a replacement from 2026 will never match a 2018 install exactly. We document this in writing before ordering.

Signs Your Unilock Home Additions & ADU Is Failing

• Stepping or lippage between pavers. One paver sits higher than its neighbor, creating a trip hazard. This usually means the bedding sand has washed out or the edge restraint has failed, often from irrigation overspray against the addition foundation.
• Efflorescence that returns after cleaning. White mineral deposits keep blooming on the surface. In Mountain View’s clay-heavy soils, this signals moisture migrating through the base from poor drainage detailing where the addition roof runoff meets the hardscape.
• Retaining wall leaning or bulging. The wall face tilts toward the planting bed or away from the grade it retains. This happens when the geogrid reinforcement was omitted or the drainage aggregate behind the wall has clogged with fine silt from our winter runoff.
• Pavers spalling or surface flaking. The top layer of concrete flakes away, exposing the aggregate beneath. On Unilock products this is rare, but we’ve seen it when de-icing salts were used (unnecessary here) or when sprinkler spray hits the same pavers daily, accelerating freeze-thaw in our occasional below-32 nights.
• Settlement cracks radiating from the addition foundation. The patio or walkway drops where it meets the new structure. This is almost always inadequate compaction of the native soil before base installation, or a missing expansion joint between the concrete foundation and the flexible pavement system.

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After

Replacement Cost & What’s Included

What drives the range: access for excavation equipment, whether we need to match discontinued Unilock colors (sourcing premium), and the condition of the substrate. A proper repair includes removal of failed material, recompaction of the base in 6-inch lifts with a plate compactor, new bedding sand, and reinstallation with polymeric joint sand. Under Clause 1 of the Haven Standard, you get a written price before any work starts, and no change proceeds without a signed change order. The 365-Day Done Right Promise covers the installation. We also stock KraftMaid, Cambria, and Silestone for interior portions of these same projects.

DIY or Call Us?

Here’s what you can safely check yourself: verify whether the problem is isolated to a few pavers or systemic across the area, look for obvious drainage blockages like clogged downspouts dumping against the hardscape, and photograph any stamped markings on loose units for identification. Do not attempt to reset retaining wall blocks or regrade against a foundation - the wall could collapse without warning, and improper grading voids most addition waterproofing warranties. The weight of even a short segmental wall is measured in tons, and the base course must be leveled to within 1/8 inch over 10 feet. We’ve been called to fix DIY wall rebuilds in Mountain View where the homeowner skipped the geogrid layers entirely. Call (669) 215-4852 and we’ll assess it properly, with a written quote before any work begins.

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