The ideal slope range for a driveway is between 2 and 15 percent. That means the driveway rises 2-15 feet for every 100 feet of length. But sometimes, especially in hilly areas, driveways can be as steep as 20% or even 25%.
If your driveway has a slope greater than 12%, it is considered to be too steep and that can cause a number of problems that we discuss below. We also include some tips on how to deal with a steep driveway.
What You'll Learn Today
- Issues Caused By A Driveway That’s Too Steep
- What to Do If Your Driveway Is Too Steep
- How to Drive on A Steep Driveway
Issues Caused By A Driveway That’s Too Steep
Vehicles Bottoming Out
If you have ever driven into or out of a steep driveway, you are probably familiar with the dreaded scraping sound as the bottom of the car grinds against the driveway.
This usually happens at two points: where the driveway meets the curb and where the driveway transitions into the garage.
The car bottoms out because you are going from a steep angle to a flat surface, causing the front or rear of the car to crunch against the driveway. This problem is especially bad if your car has a low profile. But even crossovers and trucks can still experience bottoming out on very steep driveways.
Bottoming out doesn’t just scratch your car’s undercarriage; you risk damaging crucial components that are expensive to repair or replace. Persistent bottoming out can damage the oil pan, bumper, muffler and the engine cover or skid plate.
You may not notice a problem at first, but the constant friction and impact every time your car scrapes the driveway causes a little more damage.
Difficulty Driving in Wet/Snowy Weather
Most cars can comfortably navigate a steep incline. A 25% driveway will not keep even a small car from driving up it.
That said, weather can present drivability difficulties on steep driveways. Rain, sleet or snow can easily make a steep driveway difficult, even dangerous, to drive on. You’ll struggle to gain traction on the steep slope and you could even slide and cause an accident.
Drainage and Erosion Issues
A steep driveway might seem to be great for drainage. You don’t have to worry about water pooling on the driveway. Gravity does all the work for you.
That’s true. But a too-steep slope can also cause other kinds of drainage problems.
The biggest problem is that the driveway can create more runoff than before. Because the water doesn’t drain into the ground as fast as before, more of it flows along the driveway.
This fast flowing water can cause serious flooding in the street. If your home is lower than the street, meaning the driveway slopes down towards your home, then you could experience flooding around your house.
Another issue with the fast-flowing water is erosion, which can reduce the lifespan of your driveway. Over time, the water runoff could erode your driveway as it carries away small bits of material at a time. This is worse for gravel driveways.
Note: Don’t forget that a steep driveway is also challenging for people. Walking up the driveway can be difficult especially for the elderly. People on wheelchairs might also find it impossible to go up a driveway that’s too steep.
What to Do If Your Driveway Is Too Steep
Here are five ways you can fix a steep driveway. Pick the ones that will work best for your particular situation.
1. Buy a Ramp To Prevent Bottoming Out
Let’s begin with the cheapest solution for a steep driveway — curb ramps, sometimes called curb plates.
If the biggest issue with your steep driveway is bottoming out when you drive onto the street, curb ramps can help.
These ramps bridge the transition between a steep driveway and the curb or street, which prevents the front and bottom of the car from scraping on the ground. You can also place these ramps where the driveway transitions into the garage.
Curb ramps are typically made from heavy duty rubber or plastic. They can handle the weight of vehicles and withstand the elements. We recommend ordering a pair to fit the width of your car. Check that they have drainage channels at the bottom to ensure they don’t block water flow.
Here’s a video of how curb ramps work and the best place to position them.
You can also build your own permanent ramp using concrete, but you may need to get a permit especially if you plan to make any alterations to the curb.
2. Make The Driveway Less Slippery
If your car struggles to go up the driveway when it’s wet or icy, or slides dangerously when driving down the driveway, try to improve traction on the driveway.
There are several ways to do this that don’t involve getting off-road tires for your vehicle.
- Spread gravel or sand on the driveway. This is only temporary (water will eventually carry away the material) and can be a bit unsightly, but it’s a good option if you are on a budget.
- For a more permanent solution, consider a resin-bound driveway. This is where aggregate is bound together with resin to form a solid but rough surface that has high traction. If you have a gravel driveway, you just need to pour resin on top to bind the gravel. For concrete, paver and asphalt driveways, you first add a layer of aggregate then bind it with resin.
- Coat the driveway with a high-traction sealer. These types of sealers come premixed with grit to produce a rough driveway finish. Alternatively, apply regular sealer then spread polymer grit on top before the sealer dries.
- If you have a concrete driveway, giving it a coarser texture can help improve traction. You can do this by grinding it or etching it with acid. Make sure you reseal the driveway afterwards.
3. Lift Your Truck
Lifting your vehicle may sound a bit excessive, but it’s probably the best option if you are not able to make changes to the driveway itself.
We only recommend this for trucks and SUVs that will benefit from the lift in other ways. You don’t have to spend a lot of money on lifting your vehicle. With $500 or less, you can get spacers that lift your car frame by 1-3 inches.
That should be enough to prevent bottoming out on the driveway. It will also improve your off-road adventures.
For regular cars, consider a hydraulic lift kit. It allows you to lift and lower your car. So your car will look and feel the same, but you can lift it when getting into the driveway to prevent bottoming out.
On the downside, hydraulic lift kits are pricey.
4. Improve Drainage
As we mentioned, drainage can be problematic on a driveway that is too steep. To prevent flooding and erosion, find the best ways to manage the water runoff.
One of the best ideas is a trench drain, also called a channel drain. This is a trench that you cut across the driveway then cover with a grate. As water flows down the driveway, it enters the trench. The trench is connected to a pipe that runs underground and drains the stormwater somewhere safe.
For small driveways, you can have just a single trench drain at the end of the driveway where stormwater collects. For longer driveways, consider multiple trench drains along the driveway to handle more runoff.
5. Redesign/Regrade the Driveway
In extreme cases, redesigning the driveway might be the best solution. If you have a gravel driveway, that should be relatively easy.
For concrete and asphalt driveways, regrading is more complicated and expensive. We recommend consulting a contractor for advice on how to go about it.
They may recommend demolishing the driveway or sections of it and laying it anew. They may also suggest adding overlays to parts of the driveway to adjust the grade.
Another option, which works best for large homes where space is not an issue, is adding curves or switchbacks to the driveway. This allows the driveway to slope more gently.
How to Drive on A Steep Driveway
As you figure out a solution that works, here are some tips for driving on a steep driveway without wrecking your car or causing an accident.
- To prevent bottoming out, do not approach the driveway or street straight on. Instead, you should turn as you approach or exit the driveway such that the car takes a curved path onto or off the driveway. If necessary, expand the width of the driveway at the entry/exit so you have more room to turn.
- Maintain constant speed when going up the driveway; not too fast but not too slow either. This will help you maintain traction and momentum.
- Drive even slower when going down the driveway, especially if it is wet or icy. Don’t break or accelerate suddenly as that could cause the car to slip.
- Be careful when going up the driveway as you may experience reduced visibility. Be on the lookout for pets and kids as they can be harder to spot.