A Proven Process for Basement Waterproofing


We decided to write an article about best practices for basement waterproofing that have been tested, proven and working for many years for all our clients. We are not talking about magic waterproof paints, channel drain tiles that sit on top of the footing, molding drainage system and e.c. None of them completely, and more important properly solve the wet basement issue. Most of the waterproofing systems have been designed for easy installation, and not for how well they will perform. That little box of tricks doesn’t take you very far. In fact, it sometimes takes you nowhere.

The real best practice isn’t a particular product at all. It is a well-defined series of steps that conduct to effectively performing system.

The Aquamaster Drain Plumbing & Waterproofing Inc approach is significantly different from quick fixes. We have mentioned it in conference talks, but this is the first time we’ve published an overview of it. Our approach is not based on guesswork, and it doesn’t have the excitement and appeal of magic products. In fact, in many respects it looks a lot like hard work. It requires knowledge, craft, skill, and expertise. But experience has shown that it works, time and time again. This is what we do every day for our clients.

The Aquamaster Waterproofing Methodology

Step 1: The Rules of the Successful Project: Identifying the problems, defining your long-term goals, and measuring your budget.

  • We need to find out (not guess) which parts of your foundation are under performing. We need to clearly define the problem in order to assign the appropriate solution.
  • After detailed analysis of the problem we will come up with a proper solution that fits your budget.
  • You will clearly know how much money you’re going to spend now, and possibly in the future.

We try to stay away from quick fixes, and prefer to address the problem at its roots. It is more expensive, but you pay once – guaranteed. If however, you want a quick fix – we will help you. Although you do need to realize that it is only a temporary solution which won’t last long and possibility of spending again in the future is huge.

Step 2: Understanding the hydrostatic pressure and foundation drainage.

Basements leak by various reasons, some of them are easy to identify and some are not. When it rains or snow melts lots of water travels against the foundation wall, and without proper waterproofing it quickly penetrates into the basement through foundation defects like cracks, tie-rod holes and others, as shown on picture below. Also the underground water table rises and creates hydrostatic pressure that forces water up through the basement floor. That is when weeping tile comes into action. Installed next to the footing it reliefs hydrostatic pressure and controls water table level. This is the reason why it is very important that weeping tile remains clean, free of dirt and tree roots.

pieces of clay pipe align together
Old-style weeping tiles are pieces of clay pipe align together with gaps in between; these gaps are entry points for water, but as water travels down through the soil it picks up sand, sediment and mud, which over time block the pipes. That is why we recommend using modern weeping tile, which is a perforated, corrugated plastic tube with cloth filter. Its design prevents weeping tile tube from getting blocked plus it absorbs much more water in shorter periods of time.

 
process of basement waterproofing Toronto

Types of foundations, strengths and weaknesses analysis.

There are 4 primary foundations: poured concrete, masonry, stone and concrete blocks. Each foundation has its core strengths and weaknesses. The type of foundation determines the methodology and materials to be used. Once the system is analyzed, strengths and weaknesses are assessed, and water entry points are identified, we are ready to focus on repair solutions.

Interior Drainage

Step 3: Types of waterproofing systems and making decisions based on overall overview.

We will describe two most advanced and proven systems: internal and external.

Internal system

Although interior water drainage is not technically waterproofing, it is a working technique in mitigating basement water. This technique involves removing a section of the basement concrete floor, usually about a foot wide, along the foundation wall. Then a trench is dug out where weeping tile is placed and drainage membrane is installed on the foundation wall. After that was done, trench is back filled with 3/4 grovel and new concrete is poured over it. Interior water drainage functions by draining underground water from underneath the basement floor and alongside the foundation footers. It then channels the water with a weeping tile pipe to a sump pump system, which will then pump the water from the basement outside. Wall conduits such as dimple boards or other membranes are fastened to the foundation wall and extend over the new drainage to guide any moisture down into the system.

Interior Drainage

External system

As mentioned above the materials and methodology will depend on many factors. Herein is described a process of basement waterproofing for a house with poured concrete foundation.
This process consists of well-defined series of steps.

Preparation

Plants are removed to plastic containers with top soil while waterproofing process takes place.
Job area is protected with sheets of plywood, plastic tarps and “caution” signs.

Excavation prior external basement waterproofingExcavation

The process requires excavating soil along the foundation wall 4” below the top of the footing. Why exactly 4” you may ask? That is because the diameter of weeping tile that will be later placed along the footing is 4”. Once excavation is done and old weeping tiles are out, we start treating the foundation walls.

Cleaning the Walls

We power wash the walls and then dry them up using a propane torch. After that foundation walls are inspected for cracks, holes openings and are fixed with hydraulic cement. Cleaning the walls is a very important step; it is impossible to pinpoint all defects without it, also foundation sealant that is used after won’t stick properly and as a result the entire waterproofing system will eventually fail.

Sealing

We now begin the sealing process that is exclusive to Aquamaster Drain Plumbing & Waterproofing Inc. Our first layer of protection is a cement based sealant. This material strengthens and hardens concrete walls by closing its pores. Then we apply a coating of elastomeric waterproofing membrane (polymer modified asphalt).

Exterior Basement Foundation-Excavation and Waterproofing
In contrary to the black tar this rubberized asphalt membrane is formulated to stay pliable. The great advantage of it is that even if the new cracks occur – elastomeric membrane will simply stretch and will continue to perform. Black tar has no flexibility at all and will crack with any foundation movement. Also black tar is rated as a damp-proofing not a waterproofing, it will slow down the penetration of water while, elastomerics will prevent the penetration completely. Unfortunately most home builders are still damp-proofing rather than waterproofing their foundations.

 
For our final layer of protection, we install a heavy gauge polyethylene dimpled drainage mat to the foundation wall using specially designed fasteners. This material does not tear providing reliable protection for the elastomeric membrane. The dimples create an air gap, so if moisture gets behind it, it quickly channels to the drain tile.

New Footing Tile Installation

We install the new perforated weeping tile with the “SOCK” filter on it. Clean outs are installed to provide access to the weeping tile pipe. Then we disconnect downspout pipes which will ensure that leafs and stones from the roof will not block the weeping tile, reducing the risk of flooding in the basement. You may also be eligible for rebates from the city of Toronto for doing that. More information about this program can be found here: http://www.toronto.ca/water/protecting_quality/downspout.htm
Or simply contact us at 416-939-6379

Back fill

Then we cover weeping tile with 3/4 gravel 16” on top. Many companies will use plywood to cut the trench in half. They will gravel on the house side of the wood and fill the other side with the excavated dirt. We fill the entire trench with river washed gravel as opposed to the less expensive limestone that most waterproofing contractors use. Limestone compacts which limits drainage. After that had been done we start back filling with previously excavated soil, constantly tamping it down during this process, as the result – minimum soil settling.

Landscaping

Finally, the landscaping is restored. We use premium top soil when replanting previously removed plants. Aquamaster Drain Plumbing & Waterproofing Inc takes great effort in protecting your yard and landscaping during the process. All equipment is run on plywood, so damage is minimal. Often times it is hard to tell that we were ever on your property.

The work is complete now and you have a piece of mind that it was done properly, the best possible way. Proper waterproofing is a complex process. Few companies accomplish this in a timely manner, with minimal damage to the property, and little or no inconvenience to their customers. Superior attitude produce superior results.

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I did some research and called up the company for a service call … The experience with the company has been great, as well as the pricing.

Simon, Richmond Hill