Basement Renovations

Here’s what you need to know to elevate your lower level

basement contractors

Flipping your dark (and maybe damp) basement into an actual living space can add a lot of square footage, not to mention value, to your home.

Almost all existing basements have a good shot at turning into a play area, media room, or even another bedroom and bathroom. Several factors, such as current ceiling height, local egress regulations, and insulation needs will influence how long your timeline will be and what it will cost.

The good news is on average roughly 70 percent of what you put into your basement renovation will be recouped in the value added to your property, according to REMODELING’S 2017 Cost vs. Value report. The median budget of a basement renovation in the U.S. for 2017 was about $70,000. Sweeten contractors have done projects for far less (and also far more).

There are also no deal breakers according to our Sweeten contractors. Any problem—bad plumbing, lack of natural light, high humidity, a low ceiling—can all be sorted to make your basement happen. It will all depend on how much you are willing to pay. “It’s a balancing act to how much you want to put into the house before you exceed what value it brings,” said Alan, a Sweeten contractor. “You also have to decide if cost value is important to you or is it more important to have a home you want to live in.”

Here, Sweeten, a free service matching homeowners with vetted general contractors, outlines what you need to consider when sketching out a vision for a basement remodel:

Ceiling height

While building regulations vary from town to town, contractors say the height requirement for the ceiling will be between six and seven feet. About 50 percent of basement jobs require the floor to be dug lower to allow for additional ceiling height.  This involves cracking open the existing concrete floor, which is usually one to two inches thick, removing the excess dirt and re-laying the concrete.

Second form of egress

If you envision more of a living space than a laundry and storage area, a second exit will likely be necessary. To be comfortable and have no problems with building inspectors, you will need that second form of egress, such as a window or a door with steps leading outside to ground level.  That usually means digging down to make an open passageway on one side of the building so there is a way to get in and out.


Often, homeowners will add a half or a full bath to their new basement space. The plumbing for this likely goes under the concrete flooring. This will help avoid flooding if any of the pipes burst. As your future basement living space will probably be below the sewer lines, a pump will be required to get waste out. Of course, adding a bathroom will also add to the budget, but for many, the convenience is worth it.


How much square feet you will be able to add to your basement is another factor to consider when it comes to the cost and value it adds to your house. The smallest basement renovation can add only 400 square feet of living space and be used only as a kids’ play area. The typical size of a basement space is about 1,000 square feet. And don’t forget, if you have equipment such as your home’s boiler in the basement, a mechanical room could take away a few hundred square feet from the livable space.

Waterproofing and insulation

Basements are known to be damp and account for the majority of your home’s indoor moisture. On top of the general humidity in your basement, flooding could also be an issue, so pay attention when it rains next. Rain and leaks tend to be a big source of water issues that you don’t have to deal with in the rest of the house.

The answer to this common problem is often insulation and waterproofing. And there are intelligent products that can help. If a conversion involves a bedroom, which is a room where many hours are spent, it is ultra important to keep toxic mold at bay, which is fed by moisture. In-wall products like CertainTeed’s MemBrain is an accessory to regular insulation that allows the buildup of moisture to escape while preventing moisture from entering in the first place. Its 2-step process will add a few extra days to a renovation timeline. Their SMARTBATT requires a shorter installation process for spaces like a rec room, which you likely won’t spend as much time in as a bedroom. As a one-step insulator, it blocks moisture from entering when it senses humidity at a low level in its cavity.

Even with these intelligent products, insulation requires multiple products and systems to stay on top of heat, cold, and humidity, according to Ted, a representative from CertainTeed. This could mean using spray foam to fill in cracks and seal windows and doors, as well as typical insulation products.


To prevent toxic mold, the humidity of living spaces should be below 60 percent, according to the Environmental Protection Agency. That’s why ventilation, along with insulation, is important. Relying on natural air flow from windows is possible, but its subject to the weather and seasons. Extending your home’s existing HVAC system will help ventilate the basement area. However, the ideal situation is to remove the humidity.  Exhaust fans installed into the wall or window that push damp air out while circulating the remaining air around the entire house are recommended. This system can either turn on when the lights are switched on or be equipped with sensors that switch the fans on once humidity gets above a certain level. A humidifier could also be used, but be prepared to pump that waste water up to the sewer lines.

Renovating your basement might be the easiest way to add another floor of living space to your home. Like any home construction project, there’s much to consider. But in the end, your home will increase in value and your quality of life (think noisy kids with their own playroom, or your noisy friends around a home bar with football on the big-screen TV) will improve.