How much does it cost to waterproof a basement?
According to most experts there is no way to give a "ballpark" figure for the waterproofing of a basement. This is because moisture can enter the space through a number of ways, and for a wide range of reasons. For instance, some people have condensation problems that lead them to believe there is some sort of leaking in the basement, this is something easily remedied by improving ventilation, and dehumidifying the air using a standard dehumidifying unit (averaging around $250).
For the purpose of this discussion we will consider several ways to waterproof a basement when leaking is the source of the moisture.
- Seepage: Among the most common of all reasons for water in the basement is the appearance of cracks and leaks in the basement floors and walls. This allows water from the ground to seep into the area and remain there unless removed in another way. According to Essortment.com the best way to address this problem is to install a baseboard drain leading to a sump pump 1 that removes the water mechanically. This will cost between $10.50 and $21 per square foot depending upon the size of the basement and the system selected;
- Sealing: of course the actual leaks or cracks can be mended instead of simply removing the water, and this is the best way to waterproof a basement permanently. There are several ways this can be done:
- Excavating the foundation walls and sealing all cracks with a rubberized compound is the most common approach for the homeowner working with a licensed contractor. The costs for materials are minimal (with sealants costing around $12 per gallon) and it is the labor involved that tends to make the project quite expensive. Usually the use of a small back hoe is necessary, and the installation of new fill is also a part of the process. The average professional will charge between $5k and $10k for such a project;
- Installing a curtain drain is also a good way to redirect ground water away from the home, and this is also something best done by a knowledgeable professional. This requires excavation, sealing with a moisture barrier on all parts of the exterior wall, and the placement of "French" or footer drains 2 that direct any ground water away from the foundation. This is a project that usually exceeds $10k and can run as high as the tens of thousands depending upon the "footprint 3" of the home; and
- Sealing from inside - many homeowners can easily identify the areas where water is entering the basement and can then use any of the professional grade sealants to try to prevent the water from entering through cracks. It is important to understand the proper techniques used for mending concrete in this way, but it will average at only $12 per gallon of sealant used.
Additional considerations and costs
- Gutters: many basements receive water due to a lack of gutters on the home, or due to downspouts directing too much water towards the foundation. This is a very low-cost way to waterproof the basement; and
- Windows: many basement window wells 4 collect water that leaks into the basement and the installation of covers tends to eliminate the problem instantly.
Remodeling Terms Cheat Sheet
Definitions in laymen's terms, cost considerations, pictures and things you need to know.
See full cheat sheet.
1 Sump pump
: A mechanical device used to remove water from wet areas such as basements and crawlspaces in order to help prevent flooding
2 Footer drains
: A method of protection against water entering the basement. It runs along the footer - the structure below the basement's floor that supports a house's foundation, collecting excess water and running it through pipe into a sump or away from the house.
: The entire area of ground covered by a building, including the exterior walls and porch or patio areas
4 Window wells
: A semi-circular area around a window below the grade of the house, reinforced by a sturdy material such as galvanized metal or masonry
Cost to waterproof a basement varies greatly by region (and even by zipcode). To get free estimates from local contractors, please indicate yours.