DEAR TIM: We would like to replace our driveway. My wife and are debating whether to replace the concrete driveway with another concrete driveway or a concrete paver driveway. I have concerns about the concrete pavers heaving and moving about due to the winter weather in central Ohio. I also think shoveling the snow on a paver driveway could be frustrating given the number of spaces between pavers. We’ve talked to local contractors and received different opinions. Some say pavers are a problematic choice for our climate. Others say the pitch of our driveway makes concrete a poor option. What’s your advice to get a great long-lasting job no matter which choice we make? – Scott J., Westerville, Ohio
DEAR SCOTT: I’m not a betting man, but let me guess. The concrete paver contractor said that the pitch of your driveway would make poured concrete fail. The poured concrete contractor said that pavers are problematic even though he walked across your concrete paver sidewalk to your front door. Am I close?
It’s hard to make an informed choice when you’re doled out biased information, isn’t it? Your simple driveway decision reminds me of a meeting I attended years ago. It’s relevant and I feel you’ll enjoy it.
I was elected as a councilman in my small village 15 years ago. Three other new members were swept into office, one of them a brilliant attorney I became friends with. He was an expert litigator, and somehow we began discussing a situation at a committee meeting.
“A half-truth is a whole lie,” he said at one point. That simple statement hit me like a bucket of ice water. The contractors you’re talking to are telling you half-truths. I’ve done expert witness work for more than 15 years in construction lawsuits and have been sworn in countless times. When you take an oath before a deposition or in a courtroom, there’s a reason you swear to “tell the truth, the whole truth and nothing but the truth.”
For this reason, let’s talk about the whole truth concerning poured concrete vs. concrete pavers when used as a driveway. It’s important to realize both systems are relying on Portland cement. That’s a good thing. Portland cement is the glue that holds together the sand and gravel in the poured concrete and the concrete pavers. I’ve walked across concrete sidewalks and driveways in Cincinnati that look fantastic after 70 or more years of exposure to the elements
Another key point is the concrete pavers are made in a controlled environment where they gain maximum strength. Poured concrete ordered from a ready-mix plant might not have enough cement in the mix because the contractor wants to save money.
A point often overlooked is poured concrete can be ruined not only as it’s being installed but also after the contractor drives away. He may add water to the mix as he’s finishing it and he may not apply a curing compound to slow or stop the evaporation of water from the mix.
In other words, if you decide to install poured concrete, you need to make sure the contractor knows exactly how to order, place, finish and cure it. If you want a super-strong poured driveway, I’d order it with a 5,000 pounds-per-square-inch compressive strength. This exceeds the minimum standard of 4,000 PSI.
Be sure the slump is no more than 5 inches, don’t allow any water to be added at the job site and apply a curing compound after the concrete is finished. I’d also pour the slab 6 inches thick and have 1/2-inch reinforcing steel in the slab 2 feet on center both directions. Before the pour, the steel would look like an empty sheet of graph paper.
Concrete pavers can be installed with ease and will not be a problem at all with your cold weather. The most compelling evidence is your front sidewalk. The photo you sent me shows it’s made with concrete pavers, and they look to be in excellent shape. They’re smooth, from what I can tell.
On the negative side, precast concrete paving bricks fade over time. The ultra-thin coating of colored cement paste wears off, exposing the true gray and white color of the sand and stone used to make the pavers. Many homeowners are distressed when this happens.
The key to a smooth, strong driveway made with concrete pavers is the compacted gravel base under the pavers. Not only does the soil beneath the drive need to be solid and compacted, but the crushed gravel under the pavers also needs to be well compacted. The gravel is what prevents the pavers from sinking when concentrated loads are placed on the driveway.
Shoveling snow from the driveway will never be an issue if the pavers are installed according to all the written guidelines produced by the Interlocking Concrete Pavement Institute.
Given these points, I’d also reach out to the Portland Cement Association. They’re the touchstone for trustworthy information about how concrete driveways should be installed that can last for well over 70 years.
Need an answer? All of Carter’s past columns are archived for free at www.AsktheBuilder.com.