Riverside Custom Countertops has become the Inland Empire's leading specialist in custom island tops, specializing in one-piece island slabs, seating overhangs, and prep sink cutouts. We offer quartz island tops and granite breakfast bars.
Our team provides digital laser templating of the island base, delivering island tops built for homes and long-lasting stone work for both residential and commercial projects. Backed by 12 years in business and a 1-year workmanship warranty that covers seams, fit and sink mounting, we've completed over 1,870 projects, from a compact prep island to a 42 x 84 inch island that seats four.
From the overhang depth at each stool to the carry path for a single heavy slab, our team handles every detail. Serving Riverside and neighboring Woodcrest, Chino Hills and Corona, we size every island so the stools fit, knees clear and the slab makes it through the front door.
Request a free estimate, and we will measure your island base and stool spacing before any slab is chosen.
What you can hold us to
Jill, multi-acre horse-property lots off Van Buren Boulevard, Woodcrest
Farmhouse island with a prep sink and a long gravel drive to the house
Investment and duration figures are estimates. Your written quote sets the final price and schedule.
Jill lives on one of the multi-acre horse-property lots off Van Buren Boulevard in Woodcrest, and her large farmhouse island had a prep sink and a long gravel drive between the street and the kitchen door. She wanted Ivory Fantasy granite in one piece, with no seam running through the prep sink. We walked the carry path before cutting and brought a 4-person crew, because a one-piece large farmhouse island slab is too heavy and too long for a standard two-person carry. The result was a one-piece top with no seam across the prep sink, an estimated $2,200 to $3,100 job that took an estimated 3 to 5 hours on install day.
Tear-out, laser template, new 3cm tops, undermount sink and eased edge
Standard 40 x 80 inch island, overhang support checked
Mitered vertical panel with the vein carried down the side
Slab from countertop to the upper cabinets or hood
Granite rated for sun and heat on a block or steel BBQ island
12 to 20 sq ft bar top with a bar sink cutout
Added to a replacement job; old tops removed and recycled
Investment and duration figures are estimates. Your written quote sets the final price and schedule.
| Island job | Est. investment | Est. duration on site |
|---|---|---|
| Kitchen island top (standard 40 x 80 inch island) | Est. $1,600 to $3,400 per island top | Est. 3 to 6 hours |
| Waterfall edge drop added to an island | Est. $800 to $1,800 per waterfall side | Est. 4 to 8 hours |
| Old island top tear-out and haul-away | Est. $150 to $500 per project | Est. 2 to 5 hours |
| Undermount prep sink cutout in the island | Est. $75 to $125 per sink cutout | Est. 1 to 2 hours |
Each row is a separate line on the written quote, so you can see what a waterfall drop or a prep sink adds before you decide on it.
A standard island top in our shop is estimated around a 40 x 80 inch footprint, and most Riverside kitchens fit that size with a full walkway on every side. Larger islands, like Daniel's 42 x 84 inch island in Orangecrest, still come from one slab when the layout allows it. Stone slabs are typically sold around 110 to 130 inches long and 55 to 65 inches wide, so an island much longer than a slab needs a seam, and we place it where nobody sits. Our estimator checks the slab size against your island length at the template visit, before you commit to a stone.
Seating overhang on a stone island is typically 12 in. for counter stools, and anything past 10 to 12 in. on 3cm stone gets concealed steel supports under the top. Thinner 2cm stone is generally capped near 6 in. unsupported, which is why we build islands in 3cm as our standard. Daniel's Bianco Antico granite island in Orangecrest had a 14 in. seating overhang and nothing under it, so we fitted concealed flat steel bars and the top now seats four with no corbels showing. Concealed supports are typically estimated at $150 to $500 on top of the island price, and we list them as their own line on the written quote.
A custom kitchen island top in Riverside is estimated at roughly $1,600 to $3,400 per island top installed, and the stone, the island size and any overhang support move the price most. Engineered quartz typically runs $65 to $145 per sq ft installed, granite typically runs $55 to $135 per sq ft, and natural quartzite typically runs $85 to $185 per sq ft. Victor's 40 x 80 inch island near Chino Hills State Park in Alaska White granite was an estimated $1,900 to $2,700 job, matched to the perimeter slab lot.
| Island material | Est. installed price | Island upside | Island watch-out |
|---|---|---|---|
| Engineered quartz | Est. $65 to $145 per sq ft | Never needs sealing | Hot pans can mark the resin |
| Granite | Est. $55 to $135 per sq ft | Takes heat at the cooktop side | Sealed every 1 to 2 years |
| Natural quartzite | Est. $85 to $185 per sq ft | Harder than granite, marble look | Sealed at install, then on a schedule |
| Marble | Est. $80 to $195 per sq ft | Soft veining for a baking island | Etches with citrus and vinegar |
| Solid surface | Est. $70 to $130 per sq ft | Integrated sink, no rim | Softer, scratches show sooner |
Treat these island figures as estimates, since they are subject to change with slab pricing. Your written quote after the laser template sets the final price and the install schedule, and it turns on the slab you pick, the overhang support your seating needs and any prep sink cutout.
Swapping an island top over the existing cabinet is cosmetic work, but adding or moving an island outlet needs an electrical permit under the California Electrical Code, so we plan any outlet change before the template. Stone typically weighs 15 to 22 lbs per sq ft, which puts a one-piece island slab well past what two homeowners can safely carry. A crack during the carry costs the whole slab, which is why we bring 3 to 4 installers for large island tops. Our Riverside shop cuts every island wet, and the crew sets the top already polished.
Our owner still walks the slab yard with island customers and checks the seam layout before the saw touches stone. The estimator who lasers your island base also checks stool spacing and overhang depth, so the support plan is drawn before the slab is cut. Every island top carries our 1-year workmanship warranty on seams, fit and sink mounting.
Most island customers in Riverside choose between engineered quartz island tops, granite slab islands and quartzite and exotic stone for a statement island. Bakers who want a cool, soft-veined surface often look at marble slabs for an island.
We build islands from the Wood Streets to Orangecrest and Canyon Crest, and across Woodcrest horse-property kitchens, island remodels in Chino Hills, Corona kitchens and Eastvale homes. Norco, Yorba Linda, Villa Park and Temescal Valley are on our full list of service areas.
An island is often the start of a bigger change: homeowners add waterfall edge countertops to one or both island ends, pair the island with a full-height slab backsplash on the range wall, or replace the perimeter through our countertop replacement and upgrades service.
A standard island top is estimated at roughly $1,600 to $3,400 per island top installed, and your written quote sets the final price after the laser template.
Most counter stools work with about a 12 in. overhang, and anything past 10 to 12 in. on 3cm stone gets concealed steel supports from us.
Yes, when the island fits inside one slab, which is typically 110 to 130 inches long; Jill's large farmhouse island in Woodcrest came out as one piece.
Most island tops take an estimated 3 to 6 hours on site, typically 1 to 3 weeks after the laser template.
It can match or contrast; Victor near Chino Hills State Park chose Alaska White granite from the same slab lot as his perimeter counters.
Adding or moving an island outlet needs an electrical permit in California, while swapping the stone top alone does not.
We take a deposit of no more than 10% or $1,000, whichever is less, then progress payments as the work is done.
Book a free estimate, and our estimator will laser template your island base, plan the seating overhang and give you a written, itemized quote.
Start to finish
We check the cabinets for level and take a digital laser template before any slab is cut.
You pick the slab and approve where every seam and vein will fall.
The stone is cut wet, edged and polished in our Riverside shop, cutouts included.
A crew of 2 to 3 installers sets the tops, mounts the sink and walks the job with you.
Where we work
Call us or send the form, and we will book a site visit and a laser template.
Calls only, we do not receive text messages.
