Your Wet Basement May Not Be The Result of Basement Leaks!
Sometimes you just can’t seem to figure out how water got into your basement. At this point it is important to know that not all wet basements are caused by leaks in a foundation.
On this site we have a page dedicated to the most common sources of basement leaks. As water is subjected to the force of gravity and the path of least resistance, water penetrating the envelope of your home above grade (level of the soil) and above the foundation, it is logical that these leaks will trickle downwards and often appear to be a basement leak.
Water penetration through the building envelope above grade is typically attributed to one or more of the following causes:
• Deck installation, where decks are fastened to the brick veneer using lag bolts to fasten a 2 X 8 board against the veneer (usually over the mortar joint between the top of the foundation and the brick veneer;
• Brick veneer in need of tuck pointing (hairline cracking or deteriorated mortar joints);
• Window sills in need of tuck pointing (hairline cracking or deteriorated mortar joints);
• Brick chimneys in need of tuck pointing (hairline cracking or deteriorated mortar joints);
• Deteriorated caulking around patio door frames;
Deteriorated caulking around window frames, or windows with inherent design deficiencies;
• Plumbing; leaks;
• Landscaping and/or walkways, or structures installed next to the foundation that are higher than the top of the foundation;
Deteriorated caulking around exterior door frames, or through door inserts;
• Interlocking patio stones or flagstone installed on top of the front porch slab;
• Balconies or decks located off the second floor of the home; and
• Improperly sealed light fixtures installed in the brick veneer.
Note: Most of these leaks will only manifest themselves when there are driving rains against certain walls of your home (with the exception of plumbing leaks of course). It is for this reason that AquaGuard Injection & Waterproofing® uses thermal imaging technology to locate those “hard to find” leaks.
A True Story
In 2006 AquaGuard Injection & Waterproofing® was called in to inspect a basement with a large puddle on the floor in a storage room; the homeowner was convinced that the water had entered through a foundation crack or from some other related point of entry. Upon further examination we noticed that the water had a “skin” on the surface; typically, water entering through the foundation is clear, as it is filtered by the soil outside. As we found no obvious source of water ingress in the storage room we examined a finished part of the basement separated from the storage area by a dividing wall. During our investigation we found moisture in the finished part of the basement. When we opened the wall we found that the stack (the large vertical PVC sewage pipe connected to the plumbing upstairs) was leaking. When we discovered this, the homeowner mentioned that he had called in another waterproofing contractor, the week before, to address the problem. He then told us that the other waterproofing contractor had given him an estimate of $8000.00 to waterproof the foundation! What he needed was a plumber, not a waterproofing contractor. If he had accepted the other waterproofing contractor’s solution he would have spent $8000.00 and his problem would not have been addressed at all; he would have effectively wasted his money. This is one of the reasons why AquaGuard Injection & Waterproofing® only sends skilled technicians, not salesmen, to investigate water infiltration issues.
Weatherproofing and Landscaping Tips to Avoid a Wet Basement
Caulking: It is mandatory that you maintain the caulking around your home to maintain the integrity of the building envelope with respect to water ingress. The caulking around the patio door frame is an absolute maintenance must do. Below is a picture of what can happen when water enters a home around the patio door frame.
Tuck pointing: Also referred to as “repointing”, typically involves the repair of weathered or cracked joints in old or damaged masonry. Quite often we hear our customers say that they only notice basement leaks when it rains from a certain direction; in many cases, the water enters the home through the brick veneer exterior walls where mortar joints between bricks are in need of tuck pointing. When water enters your home through the brick veneer the water runs down, behind the wall, onto the top of the foundation and sometimes travels along the top of the foundation.
Grade height and slope: The grade of the soil around your foundation should slope away from the foundation at least 5% or 15cm over the closest 3m to the foundation; this ensures that surface runoff is directed away from the foundation. Additionally, you must ensure that you keep the grade height below the top of the foundation wall. As there is often hairline cracking in the mortar joint between the top of the foundation and the first course of brick, this is an area that is susceptible to water ingress; therefore, this area must not be exposed to hydrostatic pressure. Landscapers are notorious for ignoring this fact when designing the landscape around your home. Below is a picture of proper grade height as well as real pictures of what can happen when the top of the foundation is underground because a walkway or some other landscape feature is too high relative to the top of the foundation.
All too often we see landscaping that is too high relative to the top of the foundation. Raised flowerbeds, walkways and patios are often responsible for the introduction of water over the top of the foundation and consequently water in the basement. This type of situation can only be permanently “fixed” by lowering the grade around the foundation (Yes, this means removing and re-installing a walkway or patio at a lower level, relative to the top of the foundation).
Note: Your foundation is designed to be underground, your brick walls are not.
CMHC article – Understanding and Dealing with Interactions Between Trees, Sensitive Clay Soils and Foundations.
National Research Council article – Basements: back to basics
Swales: Defined as a shallow troughlike depression that carries water mainly during rainstorms or snow melts; it is crucial that you maintain a swale between your home and that of your neighbour. A swale will efficiently channel surface runoff away from the foundations thus reducing the hydrostatic pressure against foundation walls.
Downspout drainage: It is generally recommended that the downspouts from your eavestroughs drain water at least 8 feet away from your foundation. An alternative approach (the current new home construction practice) is to use a splash block which drains towards a swale.
Note: Draining your downspouts into your weeping tile system is not recommended as this will introduce additional hydrostatic pressure against your foundation. In addition, as eavestroughs generally collect debris, such as leaves, this debris will increase the likelihood that your weeping tile system will become clogged.