The Cost of Waterproofing a Basement Yourself
Having determined the source of your basement moisture and identified the appropriate solutions to resolving it, the next question you will want answered is what will it cost. The cost of waterproofing a basement, of course will vary substantially depending on the solution(s) you will implement and whether they involve interior and/or exterior work. Most basement waterproofing solutions are specifically developed to correct a particular problem. Let's look at the various problems you're likely to encounter and ways to determine the cost of the appropriate solutions.
Condensation happens when accumulated moisture in the basement air collects or condenses on the cold surfaces of the walls. To determine if condensation is your problem, tape a square foot piece of aluminum foil to one of your basement walls. Tape the entire perimeter of the foil to the wall. Check it after a few days. If the foil surface is wet you have a condensation problem. The easiest solution to condensation is to employ a basement dehumidifier. A decent, residential dehumidifier costs about $250.
If condensation isn't taking place it's more likely that moisture is entering your basement through cracks in the walls and floors. If the amount of moisture entering your basement is small enough, a dehumidifier is still and fast and easy solution. If the moisture seepage is evident by mold and mildew on the walls, if there are noticeable signs of seepage around cracks in the concrete or mortar joints, or there is simply too much moisture for a dehumidifier to handle, you need to treat your walls by sealing the cracks then painting with a waterproof paint such as Drylok®. A tube of caulk or a quart of sealer will typically cost anywhere from $7 to $10. Moisture sealing paint such as Drylok® will typically cost anywhere from $20 to $35 per gallon depending on the retailer. A gallon of paint will cover about 100 square feet of wall surface. Measure the linear feet of your basement walls and multiply that number by the wall height in feet to determine the total number of square feet you need to paint.
More expensive interior sealing solutions are also available. One such solution is the Sani-Tred® system. It consists of a waterproofing paint called Permaflex® which costs about $100 per gallon and a sealer product which is actually a combination of a base and activator. The sealer costs about $135 per gallon. The Sani-Tred® system adds considerably to the cost of waterproofing a basement and it does require more intensive effort to apply but the advantages of choosing this system are quite evident in the results. Basement walls properly treated with Sani-Tred® simply do not leak. The system creates a wall coating that is permanently flexible so it won't crack due to seasonal shifting of the foundation. But it also penetrates and adheres to concrete, mortar, and block so it won't bubble up or pull away from the wall surface because of moisture building behind it.
If the water seepage is extensive enough that sealing the walls alone will not be sufficient, you can consider installing a baseboard drainage system. There are do-it-yourself drainage kits available in many hardware stores. A typical kit covering 20 linear feet of wall will cost about $250. Kits covering larger lengths of wall will obviously be more expensive but cost less per linear foot. These systems are intended to be used with an interior sump pump or a conveniently located floor drain. If you have neither of these you need to consider the cost of installing one or the other as well.
Moving outside, you may need to put some work into your diversion system. Recall that your diversion system is the network of gutters and spouts that prevents rainwater collecting on your roof from entering your basement by diverting it away. Aluminum gutters and downspouts can range in cost anywhere from $0.60 to $3.00 per linear foot depending on the quality and thickness. You'll also need to factor in the cost of any necessary accessories such as elbow joints, end caps, and mounting hardware. These items cost very little individually but they can add up if the scope of your project is substantial.
Often times, the problem with an existing diversion system is not the gutters or spouts themselves but rather where they empty. We mentioned on a previous page that downspouts need to empty at least five feet from the foundation walls on ground sloping away from the wall. If this is not the case, a simple solution is to attach a flexible, corrugated pipe to the spout leading away from the walls. A 100 foot roll of flexible drain pipe can cost as little as $50.
Exterior Barriers and Drainage
More severe water problems will add more to the cost of waterproofing a basement. In some cases, interior solutions plus diversion systems are not enough and you have to consider more extensive measures. Most exterior barrier and drainage solutions include some amount of excavation around the foundation walls to expose them. This is a major source of cost. If you're simply planning on filling cracks and applying sealer to the walls you can excavate small portions at one time. You may even elect to only treat the troublesome areas of the walls rather than the entire perimeter. In these cases you can do the digging by hand or rent an excavator or about $300 a day.
The barrier and sealer products for exterior application vary substantially in price. Most products are offered in 5 gallon cans covering anywhere from 400 to 1000 sq ft of wall space depending on the product and the wall material. Poured concrete walls require less product than block because of the smooth surface. Product prices will vary anywhere from $100 to $250 for a 5 gallon drum.
If you're excavating to install drainage, expect to pay at least $5000 for the average sized home. Remember that you must excavate not only the entire perimeter of the home but also a pathway leading to municipal storm drains or some other natural drainage point. Additionally, you'll need to add in the material costs of the drainage system. This basically amounts to aggregate and piping which will be a fraction of the excavation costs but you'll also need to consider the amount of labor involved installing the system. Unless you're experienced in this kind of work you will be better off contracting for professional installation of your exterior drainage system. If you're still not sure what solution is right for you, let's us help by giving you more information.