This is Why Garage Floors are Lower than the House

If you are out shopping for a house, you may wonder why some houses have the garage floor on a lower level than the house floor. More houses are straying away from this once required building code, but there are still many on the market that may leave you scratching your head.

Garage floors are lower than the house for several reasons, such as:

  • Concern about water intrusion from the garage to the house
  • Fuel or hazardous liquids or vapor leaking into the house
  • Old building codes mandated it

Though many don’t stress over the garage floor level, it is still a concern for some. You may live somewhere that gets plenty of floods throughout the year or you may be in a position where fuel leakage is an issue you deal with. Regardless of what your issue may be, read below to get an explanation of all of it!

This is Why Garage Floors are Lower than the House

The main reason why some houses are built on a different level than the garage is to simply protect the house from anything that could enter through the garage. You’d be surprised at the dangers that can enter the house through the garage in the form of rain, lawnmowers, and other machines.

Obviously, everyone’s experience is different so one house may have been built this way for one reason, but another house may have been built this way for a completely different reason. It all depends on the location, who owns the house, and who built the house.

For example, if someone who is handicapped lives or visits a certain house often, some may want the garage entering directly into the house without any elevation change. 

But, usually, the main house’s floor elevation makes people feel more comfortable. They don’t have to worry when their location is put under a flood warning and they aren’t home to put down any reinforcements to keep the water from entering. Instead, it’s just the garage that may get wet, and the rest of the house is safe.

Water Intrusion

If you live in an area where floods are common, you’ve probably already thought of water intrusion. If a flood gets severe enough, your garage could become a beacon for high levels of water. There are solutions to this besides the garage floor being on a lower level, but it certainly isn’t a bad solution to a potentially serious situation.

To keep floods away, the separation between the house and garage level must be deep enough to keep from the water entering the house. There’s no one who would want to come home from a long day of work to see 6 inches of rain invading their own home from the garage.

With at least 4 inches between the garage and house floor, you are more likely to come home with a dry floor. However, rain from hurricanes or any other severe storms may still prevail at getting water into the house. However, as mentioned earlier, there are other ways you can prevent water intrusion.

Sloped Garage Floor

Many houses pair this with the house floor elevation to further waterproof the house floor. The idea is that a floor sloped towards the garage door would allow the water to stay out of the garage. Even if it does manage to get high enough to rise up the slope, it certainly won’t in a way that should be a concern.

Besides being one of many ways to keep water out of the house, it also allows households with handicapped members to feel included while the house is being built. Since a sloped floor can be done without the need of steps into the house, this eases the mind of anyone who helps transport the handicapped members in and out of the house.

Most building codes now require a sloped garage floor rather than the elevation to assist people with handicaps. However, there are still many houses being built that are built with the floor elevation.


The other option to avoid any water entering the house is the same way we avoid any water leaving the shower and ruining the bathroom floors– water drains. By using water drains, you are controlling the flow of water in your garage to avoid any damage or water intrusion.

The two drain options are trench and square or round. While trench drains allow maximum water flow control, square or round drains are much cheaper and easier to install.

Trench drains come in sections. You can either use one section, or you can use multiple sections for maximum protection. According to Everything About Concrete, it is recommended to make trench concrete out of polymer concrete with a galvanized grate on top. It’s also easier to install trench drains with the pitch already built into the drain which Everything About Concrete also talks about.

Square or round drains are the easier options for your wallet and whoever is installing it. They are also recommended to be installed in the middle of the garage floor. For more information on both drain types, click here.

Fuel Leaks

If you’ve walked into your garage to see that your car has leaked fuel onto the garage floor, you’re probably far too familiar with the fear of the fuel affecting the inside of your house in any way.

Fuel leaks can be very serious in the grand scheme of things, and you should always be very careful with any type of fuel or gas that could potentially be hazardous. This is another reason why garages are lower than the rest of the house.

There are more scenarios to keep in mind. Though storing a lawnmower in a garage is not recommended, if you happen to store it in your garage, it could leak fuel. There are also some who store fuel or any other hazardous liquid in their garage. If you do store fuel in your garage, be sure that it is stored away from the door going into your house for further protection.

Burning fuel can also release fumes of carbon monoxide or gasoline vapors into the air which can be very dangerous if brought into the house. This can be a serious issue in some cases, and even though elevating the house floor isn’t all you should do to prevent this, it can help. You should also consider sealing your door and keeping it shut as much as possible.

Is it Illegal to Have Them On The Same Level?

At one time, building codes required at least four inches to separate the garage and house floor. Recently, things have changed as disabilities are thought of more than before. If someone who has a wheelchair wants to go into a garage that is a lower level, there are certain to be difficulties rather than having a smooth transfer.

For most building codes, there are some requirements such as a sloped garage floor to prevent the intrusion of water into the house. However, building codes are different everywhere you go so make sure to be sure of what is required for your garage.

This is Why Garage Floors are Lower than the House: Now You Know

Separating your garage floor from your house floor isn’t required anymore, but there are still plenty of houses out there that are built that way. In many places, flooding is a major issue that plays into why the house floor is elevated. There are other issues such as fuel leaks that you must consider, but keep in mind that there are other ways you can go about this to make your house more handicap accessible.