Wernimont recommends waiting 24 hours for the waterproofing product to cure before backfilling to prevent damage. Excel Concrete has two workers on each foundation waterproofing installation, one running the sprayer and the other putting up 1/4-in. drain and dry board as the spraying is completed. "This wicks the water down to the tile to keep it away from the wall and routes it to the sump pit while protecting the waterproofing," notes Greemann. Waiting too long to backfill can damage membrane waterproofing because excessive ultraviolet exposure can cause the upper portion of the membrane to delaminate.
The bottom line
Waterproofing can be more profitable than building the concrete foundation or basement. With the sheet membrane system, it takes about a week to waterproof a $10,000 concrete job, and the contractor will be paid about $1,500 for the waterproofing work. Kazemi says adding waterproofing has added 3 to 5 percent to his profits.
At Stephens & Smith, waterproofing adds only $500-$600 to a $15,000-$16,000 home foundation, and the work is done in three to four hours. They are hired to waterproof almost all of their foundation jobs, as is Excel Concrete, where the price is $1,200 to $1,800 per job and the work is finished in 90 minutes or less. At Tri-State, waterproofing for a $25,000 foundation costs the buyer $1,500 and takes two hours at most. While Greemann says waterproofing has not increased business much, it has pumped up profits 5 to 6 percent.
Being able to waterproof concrete foundations makes a concrete contractor more valuable to a homebuilder or general contractor. Offering a complete package of services saves them money and puts more dollars in the concrete contractor's pocket.
Jean Feingold is a Gainesville, Fla.-based freelance writer who frequently covers concrete and other construction-related topics.