Waterproofing refers to the technique of keeping a structure safe from water. Any structure that is built below ground level, like a basement, has to be waterproofed. Basement waterproofing prevents basements from smelling damp and musty and keeps them safe from the ravages of water and moisture. It keeps water out, as water can be very damaging to a structure, especially a basement. Over a period of time, basements tend to get leaky, musty smelling and damp, due to excess moisture. This prevents a homeowner from a putting a basement to good use. Once a basement has been waterproofed, it is clean, dry and comfortable, and can easily be used as a guest room, an extra bedroom or even a recreation room.
Waterproofing can be done either by waterproofing the interior walls, which can be done without professional help, or waterproofing the exterior of the basement, which is costlier, but is the better option.
The interior walls of the basement can be coated with a layer of cement-like, waterproof coating. There are two types of waterproof coatings available in the market concrete based, and silicate based.
- Densifers- The silicate-based coatings, such as Liqui-hard or Krystol Internal Membrane, are only suitable for walls that have not been painted yet. These soak into the walls forming a waterproof surface. You need to apply at least two coats. This cost about $50 for one gallon, which covers about 200 sq. ft.
- Waterproofing paint, which is like acrylic paint, can also be used for interior walls. (This is sold as Kilz Masonry or Watertite LV). It has to be applied very thickly, and needs at least 3- 4 coats to be effective. One gallon only covers about 75 sq. feet, so you will need to buy quite a bit more than you would if buying paint.
- Concrete waterproofing coating- This is a very thick product that is brushed on. It dries like cement. You cannot use these if your walls have already been sealed or painted. This is sold under the name of Seal-krete, or Thoro-seal.
- Plastic sheets- these do not keep water out of the basement, they simply keep the water contained to the walls. Water that runs done the back of this sheet is lead to a drainage system in the floor. You can buy enough Polwall or Plastix, for example, to waterproof a 20×20 basement for about $5000, but you will also need to have the drainage system in place.
Exterior waterproofing of a house or basement is usually done with the help of a professional plumber. It is very important to hire a reliable, well trained plumber for this task.
- The plumber will first wash the walls and seal the cracks, if any, to ensure that the source of moisture is blocked.
- After that, the walls will be washed with a sealant, or a damp proofing compound, to prevent moisture from entering the basement.
- Then, a polyethylene plastic -membrane based waterproofing material will be applied to the walls of the basement to prevent damage caused by flowing groundwater.
- Last of all, the newly waterproofed foundation of your home will be buried again.
Which Option Is Better
For the long run, exterior waterproofing is the best bet. It can be done by the homeowner, but it is much better to call a professional plumber to do the work. Though exterior waterproofing is expensive, it is extremely safe and reliable. A sure shot way to ensure a dry and comfortable basement that is not plagued by leakage issues is to get your home professionally waterproofed. If you choose to do interior waterproofing, you may find that a densifier or concrete waterproof coat will work best.