What to expect with basement waterproofing
This article was updated on May 8, 2012.
A wet basement can be a homeowner’s nightmare.
From a finished basement that’s soaked to a basement with persistent leaks or dampness, water is no friend to your home.
If you’ve experienced leaking walls, floors or cracks in your home’s basement, it’s likely you need the help of an experienced basement waterproofing contractor.
But you’ll quickly find there are a variety of choices in basement waterproofing repairs or systems designed to tackle the problem, as well as opinions about which one is the most effective.
Start with the source
If you’re noticing water in your basement, investigating the solution should start outside your home. The first question to answer is how is the water making its way to your basement? Make sure all your home’s gutters, downspouts or other drainage systems are working effectively and diverting water away from the home.
The grade of soil around the foundation should encourage water to flow away from exterior walls, not toward them. “Roof drainage and having a positive grade away from the foundation are both very important,” says Bruce Phillips of highly rated Phillips Waterproofing in New Albany, Ohio. Basement windows should be also be above ground-level and tested to ensure they have a watertight seal.
Making sure you preventatively stop water problems originating from gutters, downspouts or the grading around the foundation can help you avoid spending thousands of dollars on basement waterproofing.
“Maintenance, maintenance, maintenance,” says Bill Sackenheim of highly Jaco Waterproofing in Fairfield, Ohio. “Keep gutters clean, downspouts away from the house, do not build mulch beds up too high - keep water flowing away from the home as much as possible."
Get bids from several companies
It’s a significant investment to hire a contractor to perform basement waterproofing: minor repairs can cost as little as $300 to $500, but more complex systems can cost as high as $2,000 to $20,000 depending on the problem and how much area it affects.
That’s why it’s important to get several estimates from different companies. Many basement waterproofing companies Angie’s List spoke with pointed out that some competing companies prefer to rely on sales tactics, not quality repairs, to obtain customers.
“You want a company that makes a thorough evaluation of the inside and outside of the home,” says Matthew Stock of highly rated U.S. Waterproofing in Chicago. “If they’re only looking at one issue, rather than the whole picture, that should be a red flag.”
Scare tactics or high-pressure sales approaches should be avoided. “Get several estimates, don't allow high-pressure sales pitches to sway your decision and ask around for someone you can trust," Sackenheim says.
Go with a problem-solving approach
Waterproofing contractors Angie’s List spoke with tended to agree: one size doesn’t fit all. “With basement waterproofing, each situation is unique,” says Wade Weeks, a manager with highly rated Basement Restoration Technologies in Cincinnati. “You should avoid systems that were not designed specifically for the situation you have.”
Every basement water problem is unique and the solution should be tailored to the job. “The majority of our basement problems are a combination of events, not one thing that one system would fit,” says Terry Chubb of highly rated Chubb Construction, a basement waterproofing company in Wickliffe, Ohio. “It could be cracking or deterioration of the basement walls, movement in the foundation walls, improper backfilling when built, clogged footer drains or deteriorated sewer lines.”
Types of remedial basement waterproofing solutions
What type of basement waterproofing repair system you choose to install is dependent on your home’s unique situation and construction, including what type of foundation system is in place. It’s also important to note that in many cases, not just one type of repair, but rather a combination of approaches, may be necessary.
Waterproofing primer or paint products
One waterproofing repair that most contractors did not recommend was waterproofing paints or primer. They cited that covering over a wall that has leaked produces little more than a cosmetic solution if the source of the water problem is not addressed.
This repair approach is generally only suitable for poured concrete foundations where seepage is originating from the walls (and not floors), Stock says. Masonry foundations, such as brick, stone or cinder block are not ideal candidates.
Injecting an epoxy or polyurethane material into a crack can help prevent water from entering the basement, but some basement waterproofing companies regard this solution as a Band-Aid and not a permanent solution.
Typical cost: $300 to $500 depending on the size and length of the crack.
Exterior excavation waterproofing
Exterior waterproofing involves excavating 6 to 8 feet deep down to the foundation wall footer and correcting drainage by installing new drainage tiles or a French drain system. At the same time, waterproofing companies will also typically apply a waterproof material or membrane to the exterior wall’s surface to make sure that water doesn’t infiltrate it again.
Depending on the number of areas affected by water infiltration, exterior waterproofing - also known as positive side waterproofing since it deals with the source of water or hydrostatic pressure - may involve one wall of a home’s foundation, or multiple walls – which would increase the project’s overall cost.
Due to the extensive excavation required, exterior waterproofing is often more expensive than other methods. However, it carries the advantage of excluding water from the home and requires little to no ongoing maintenance once the project is complete.
“You’re stopping the water from penetrating the wall and entering the basement,” Chubb says, adding that 95 percent of his company’s work is exterior excavation waterproofing.
The downside, other than cost, is the disruption to the home’s landscaping and attached features such as porches and driveways. Be sure to ask about what your property will look after the work is complete. A exterior waterproofing company that takes a comprehensive approach should have a plan in place to minimize the impact to your home's appearance from alterations caused by exterior excavation. Exterior excavation may also be a poor option for homes that are situated in high water table area, Chubb says.
Typical project cost: $80 - $100 per linear foot
Interior excavation waterproofing
A more recent innovation in basement waterproofing, contractors say homeowners often choose an interior waterproofing method because it costs significantly less than exterior waterproofing. “It’s the most common and least invasive system,” Phillips says.
Interior drain system waterproofing will address hydrostatic pressure – that is, the pressure of groundwater forcing its way through the basement walls or foundations. Because interior perimeter drain systems deal with water after it has entered a basement, it may be referred to as negative side waterproofing.
Some contractors also prefer the terms “water control” or “water management” since these systems primarily deal with water in the basement after the fact, rather than preventing it from entering the home.
“It’s jackhammering the concrete floor to install new drainage and a sump pump system,” Sackenheim says. Systems vary, but typically a contractor will excavate a trench 4 to 18 inches wide within the perimeter of the basement. Drainage tiles or piping is then installed that routes water from seepage areas to a sump pump system. To remain effective, the pipes or drainage tiles must remain free of obstructions or clogs; some contractors will install access ports for maintenance.
Another key part of the system is a working sump pump to actively remove water once it has entered the home. With this type of system, waterproofing contractors also suggest that a backup battery-operated sump pump is an essential consideration to prevent water from overtaking the basement during power outages.
While interior excavation and drainage systems are less costly than exterior systems, they’re not without their drawbacks. Excavating in a finished basement obviously presents issues for a homeowner and some contractors advise that there’s a possibility of structural damage when compromising the integrity of a concrete basement floor.
Typical project cost: $50 - $75 per linear foot
Continue reading: 6 Questions to Ask a Basement Waterproofing Contractor