Waterproofing is a term that is commonly thrown around by contractors referring to all types of different products, systems and methods designed to stop, prevent or impede water infiltration through a structure, and in our case, a foundation. In residential applications, especially in repair and restoration situations, the term waterproofing is often misused to describe damproofing, water control and drainage.
Most contractors interchange these terms and throw them around like they mean the same thing even though it couldn’t be further from the truth. And what’s more is that many don’t understand the difference. While all three approaches may result in a dry basement, the processes, application and effectiveness are very different.
When determining what your needs are and which way is the best way for you to go, you first must understand what the terminology means.
Waterproofing is a compound word from the words water and proofing. Merriam-Webster defines waterproofing as:
- 1. a: the act or process of making something waterproof
b: the condition of being made waterproof
- 2. something (as a coating) capable of imparting waterproofness
And goes on to define waterproof as:
impervious to water; especially: covered or treated with a material (as a solution of rubber) to prevent permeation by water
Dictionary.com defines damproofing as:
- 1. resistant to dampness or the effects of dampness.
verb (used with object)
2. to make dampproof.
Although a dictionary definition for Water Control could not be found, it’s commonly referred to as the act of controlling water and water flow, most often through drainage.
By its definition, waterproofing is a process that makes a foundation impervious to water. Most waterproofing contractors only get half the equation; they waterproof the foundation’s walls, but not the floor. Instead of waterproofing the floor (which is very difficult to do once a home is built), they rely on drainage (a draintile placed beside the foundation’s footing) to prevent hydrostatic pressure and keep water from coming through the floor/wall joint and cracks in the floor.
This kind of approach is actually a hybrid of waterproofing and water control and is a cost-effective, practical solution not to mention a pretty successful way to keep water out of your basement, but it’s not waterproofing; it’s elements of waterproofing combined with water control.
Concrete is pourous which means that it will allow water and moisture to pass through it, so in order to make your foundation “waterproof”, some sort of coating has to be applied to the concrete. This is normally done by the application of an elastomeric (e•lasto•meric) waterproofing membrane or a crystalline waterproofing material. To truly waterproof a foundation, the floor must also be water proofed.
The elastomeric membrane approach is a good one, but is extremely difficult to do once the house is built which usually makes it cost prohibitive. But, if you’re building a home, especially in a wet, swampy area, waterproofing your foundation during construction can be an excellent choice to ensure a dry basement. The process completely encapsulates the entire below grade portion of the foundation in a flexible, rubber envelope that prevents water and moisture from ever coming in contact with the concrete.
Crystalline waterproofing technology was invented by the Dutch in Holland decades ago, but has only been available in the North American market for about the last twenty years. It works by closing off the capillaries inside the concrete, making it more dense and thus, impervious to moisture and water. The crystalline growth re-starts every time it is exposed to moisture. So, if the foundation settles or moves otherwise and a crack forms, as soon as water comes in contact with the material, crystalline growth starts happening immediately to shut off the leak. Crystalline waterproofing materials can be added to the concrete mix in the truck before the concrete is placed, can be added as a shake-on power and trowelled into a wet concrete mix or it can be applied over cured concrete.
Water Control methods simply keep water out of your basement or control it when it does enter. They all work on the basic premise of collecting water from area where you don’t want it and divert it to another area. If your home was built after 1976, it was built with a weeping system installed at the bottom of your foundation wall and is supposed to be beside the footing, although often it is not. The weeping tile collects surface water making its way down through the soil to the water table and water from a rising water table. It is water control.
Lot grading, French drain systems, weeping tile systems, sub-floor drainage systems and sump pumps, air-gap (dimpled) membranes are all methods of water control.
Sub-floor drainage systems are not only very effective, but often the most cost effective way to keep your basement dry. They also last much longer than tradition exterior drainage systems, are more environmentally friendly, and less disruptive to your life.
DAMPROOFING is the term commonly referring to asphalt (bitumen) based coating that is applied to the outside surface of a concrete wall to prevent moisture from the soil from passing through the concrete into your basement. It can be applied by roller, brush or spray. It is typically a very thin coating and is not capable of bridging cracks. See, the soil around your foundation is at or near 100% humidity and moisture travels from areas of high humidity to areas of lower humidity. And, since concrete is porous, a bare concrete wall in direct contact with damp soil allows moisture to migrate into your living space, significantly increasing the relative humidity in your basement and severely reducing the livability and enjoyment of your basement too. There is one other concern as well; efflorescence. Efflorescence is a white powdery to chalky substance that appears to “grow” on your foundation wall and is often mistake as mould. Efflorescence is simply the naturally occurring “salts” in the concrete migrating to the inside surface of the foundation with the moisture as it passes through. Damproofing your foundation walls prevent moisture migration and efflorescence.
The National Building Code only requires that a damproofing material be applied to the foundation walls below ground level and a drain tile be installed beside the foundation’s footing. Damproofing is only intended to eliminate moisture migration through the concrete wall and does not resist hydrostatic pressure nor does it bridge cracks in the foundation walls. The drain tile is to collect surface and ground water and drain it away from the foundation; water control.
Injection is a great solution to stop water infiltration through foundation wall cracks and can be considered a variant of waterproofing. Many don’t understand the theory behind injection and therefore get it wrong, but when done properly, injections are affordable (they normally cost only a matter of hundreds of dollars) and flexible, permanent repairs.
Now that you know that difference between waterproofing, water control and damproofing, you can make an educated decision on which approach is best for you!