Concrete contractor in Mercer Island - flat, well-drained slabs on sloped lots
Kirkland Concrete Company is a concrete contractor based in Kirkland that pours driveways, patios, steps, walls and foundations on Mercer Island, with the base dug out, packed and set to drain before any concrete arrives.
Mercer Island as we see it from the driveway
Mercer Island sits in Lake Washington just east of Seattle, a short drive across the water from Bellevue, and it's almost all homes, built close together and well kept. A lot of them are big, costly houses on hillsides that fall toward the lake, with driveways that climb from the street and patios cut into the slope, so the work here tends to be replacing a tired driveway, adding steps or holding back a bank.
The ground is what I watch. Many of the island's homes are built on landslide-prone ground, so before we talk about a finish I want to know what's under the slab and where the water goes when it rains.
What we've learned working on Mercer Island lots
On Mercer Island, the city's Building Team reviews construction projects against the building codes, and a separate city team handles zoning, shoreline permits and variances, so the city's permit office at (206) 275-7600 is where to ask whether your slab, wall or footing needs a permit. When a job needs one, I tell you at the estimate and we take care of the application or walk you through it, and the city's review, not our calendar, sets the earliest start. You can also check two things about any contractor you're weighing, that they're registered with the state and that Mercer Island is added as an endorsement on their Washington business license, because the city requires that of every business working here. We're licensed and fully insured, and I've run this company since 2013.
Getting here is a trip over I-90, and once we're on the island the streets are narrow and steep, so working out where the truck parks and whether we need a pump is part of the estimate. That's a different job from the roomier lots out around Cottage Lake, and it shows in the price, which here mostly follows the slope and how hard the spot is to reach. The schedule turns on the city's review, the weather and, on some slope lots, the time of year, and you get your own figure and the plan at the estimate.
What sloped lots and wet winters do to concrete here
On a hillside, water runs downhill and finds the low edge of your slab, and if the base under it was only raked level, the soil settles or washes out and you end up with sinking, uneven panels and water pooling against the house. We dig out to firm ground, pack the subgrade, the soil the slab sits on, in layers and set the slab to fall away from the house. That costs more up front than a fancier finish, and it's the last thing I'd cut from a budget, because you can redo a surface later but not the ground under it.
Steps, walls and anything carrying weight need footings set deep enough, and the city's residential code puts the frost line, how deep the ground can freeze, at 12 inches here, so we set footings below it. For a garage or shop on a slab, our slab foundation building work starts from that same dug-out, packed base.
Get a free on-site estimate for your Mercer Island project
Send the form and we'll get back to you within one business day to set a time. I come out to Mercer Island myself, look over the site, hear what you have in mind and walk you through the plan and a free estimate, with no obligation to book.
(425) 285-8643How a concrete job goes when you call us on Mercer Island
Call or send us a note
Call (425) 285-8643 or use the form and tell us what you want poured and where it sits on the lot. A few photos of the spot and the street out front help me plan the visit.
I come out and walk it
I look at the slope, where the water runs, what's coming out and how a truck gets in, and I listen to what you have in mind. Then I go over the plan and the estimate with you right there.
Plan the truck and street
If the truck, a pump or a delivery has to sit in the street or block a sidewalk, the city requires a Right of Way Use permit for that, so we sort it out before pour day. Street work generally runs 9 am to 3:30 pm on school days and can be tighter on a school bus route, so we book the pour around it.
Dig, pack and form
Our crew digs out, packs the base and sets the forms, and all of it is ready well ahead of the concrete truck. I'm on site running the crew while the work gets done.
Pour, finish and let it cure
We pour over rebar where the slab calls for it, the steel that holds it together, and finish the top, often with a broom finish, a brushed texture that grips when it's wet. Then it has to cure, the slow hardening before it takes weight, and I'll tell you when you can walk on it and when you can drive on it.
Finished driveways, patios and steps
Mercer Island concrete questions we hear
How much does a new concrete driveway cost on Mercer Island?
You'll get your figure at the free estimate, because on the island the site moves the price more than the concrete does. Tearing out the old slab, how deep we dig and how much base comes in, forming on a slope and whether the truck can reach or we need a pump all add up, and so can a permit or an engineer's report. A plain broom finish costs less than stamped or decorative concrete, so that's the place to save if you need to.
What is the best way to plan grading on a steep lot on Mercer Island?
Plan it for the dry months, because on lots the city classes as erosion, potential slide or steep slope hazard, clearing, grading, filling and foundation work aren't allowed from October 1 to April 1. The city can grant a waiver when there's a compelling reason backed by a geotechnical evaluation of the site and the work, but I wouldn't build a schedule around getting one. If your project is on a slope, call early so we can fit it inside that window.
Do I need a geotechnical report for a slab or foundation on Mercer Island?
Yes, if the structure will sit in a sensitive or critical area, which the city counts as landslide, steep slope, seismic, erosion, flood, wetland, stream and coal mine hazard areas. A Washington-licensed geotechnical, geological or structural engineer signs and stamps the report, and each one includes a statement of risk. We build the footings and base to what that report calls for, since on that kind of ground the engineer's findings carry the job.
Do I need a tree permit to put in a driveway or patio on Mercer Island?
If the work means taking out or cutting back a tree, plan on one, because the city's own guidance says the answer to whether you need a tree permit is almost always yes. I point out any trees near the dig at the estimate so you can ask the city early.
Does a concrete contractor need to be registered in Washington?
Yes, the state requires every construction contractor to register with the Department of Labor & Industries. On any home job of $1,000 or more, a registered contractor also has to give you the state's disclosure statement, a notice to customers, so expect one from whoever you hire.
What causes a new concrete driveway to crack on a sloped lot?
The cracks that matter usually come from the ground moving under the slab, either from a base that was raked level instead of dug out and packed, or from water running underneath and carrying soil away. All concrete shrinks a little as it cures, so we cut control joints, shallow grooves that give a crack a straight line to follow, and we cut them on time instead of skipping them. Nobody can honestly promise a slab that never cracks, but with a packed base and the water sent away from it, cracks tend to stay thin and flat instead of turning into a sunken panel.
Tell us about your Mercer Island concrete job
Call (425) 285-8643 or send the form, and if your lot is on a slope, reaching out before fall leaves room to get the digging done in the dry months.