A proven process for basement waterproofing

Someone suggested we write an article about best practices for waterproofing. You know the kind of thing: magic sealants that work, “killer” waterproofing techniques, repellants, etc. Unfortunately, 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 or technique at all. It’s a well-defined, systematic process—a series of steps you need to take.

The Aquamaster Drain Plumbing & Waterproofing Inc approach is significantly different from quick fixes. We’ve mentioned it in conference talks, but this is the first time we’ve published an overview of it. It doesn’t involve 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 intelligence, experience, craft, and expertise. But experience has shown that it works, time and time again. It’s 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.

Many companies offer systematic one-fits-all approach. We advise you to resist the urge at this stage. Here are a few reasons why:

• You need to find out (not guess) which parts of your foundation are underperforming
• Many clients come to us with a preconceived idea of what should be worked on. Ironically, the problems usually lie elsewhere. First, we insist on discussing a detailed analysis of the problem. You need to clearly define your problem in order to assign the appropriate solution.
• You need to clearly know how much money you're willing to spend now, and possibly later on.

 

We try and stay away from fixes, and prefer to address the problem at its roots. Its more expensive, but you pay once - guaranteed. If however, you want a fix - we will help you. You do need to realize the implications and live with possibility of spending again in the future.

 Step 2: Understanding the foundation, drainage, pressure roles in waterproofing and making decisions based on overall system overview.

It’s impossible to come up with a plan without knowing what caused the leaks in the first place. You may have an obvious answer - water..! Yes, but we do like to go a little deeper and overview how all the elements work together, which ones broke down, why and approximately when.  This phrase is done without the excavation since our experts are able to determine the type of foundation, drainage and pressures around the house. Also having worked in many areas around GTA we more less know what's under there in various neighborhoods.

Once the system is analyzed, strength and weaknesses are assessed, and water entry points as well as trails, are identified.

Type of foundations, strengths and weaknesses analysis

There are 3 primary foundations: poured concrete, masonry, concrete blocks. Each foundation has its core strengths and weaknesses. For instance poured concrete does not have joints, and is essentially a whole piece. It however cracks with time, therefore strengthening sealants must be used to increase the longevity. 

The type of foundation determines the methodology and materials used.

Type of drainage system

Although interior water drainage is not technically waterproofing, it is a working technique in mitigating basement water. Interior water drainage functions by draining underground water from alongside the foundation footers and underneath the basement floor. It then channels it with a French drain, PVC pipe, or through a patented products to a sump pump system, which will then pump the water from the basement. 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.

The type and the working order of the drainage system sometimes requires an installation of a new one.

Step 3: The Labor Process

The process requires excavating to the footing, or the bottom of the foundation, replacing both sets of drainage tile, footing and downspout, and treating the walls. 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, French drain, a medium slope.

Excavating

The first step in the process is to excavate and haul all earth from around the walls. This removes the expansive clay which eliminates the pressure that causes wall cracking.

Cleaning the Walls

We clean the walls and inspect for cracks or openings.  This is the one opportunity to make repairs and strengthen the foundation. 

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 the concrete by closing the pores.  It also repairs hairline cracks.

We then apply a coating of elastomeric waterproofing.  Elastomeric membranes are a polymer modified asphalt.  It is formulated to stay pliable.  Elastomerics self heal if new cracks occur.  Tar has no flexibility and will crack with any foundation movement . Tar will slow down the penetration of water under pressure, elastomerics will prevent the penetration completely.  As a result, tar is classified as a damproofer, elastomerics a waterproofer. Elastomeric membranes have been used commercially for deep foundations for almost twenty years.  The roofing and window trades have taken notice of the benefits of elastomerics, yet the waterproofing industry still predominately uses the inferior product.  Most new home builders are still damproofing rather than waterproofing their foundations.

For our final layer of protection, we hang a heavy gauge polyethylene dimpled drainage mat.  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 channels to the drain tile without ever contacting your wall.  We cut the drainage mat to the exact depth of your foundation.

New Footing Tile Installation

We install the new perforated weeping tile. This is the drain tile that will keep the water level lower than the basement floor.  At this level the basement remains free of pressure and will not leak.

Clean outs are installed to provide access to the footing tile in the event they need cleaned or snaked.

We back fill with gravel and disconnect downspout lines.  This ensures leafs and stones from the roof will not block the weeping tile, reducing the risk of flooding in the basement. You will also be eligible for rebates from the city for discounnectng the downspout lines. More information can be found here: http://www.toronto.ca/water/protecting_quality/downspout.htm

Also make sure to talk to us about this: (416) 939-6379

We then continue to back fill with gravel.  We exceed code and back fill to 18" from grade for earth areas, and 4" from grade where cement will be poured.  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 clay.  We fill the entire trench with river washed gravel as opposed to the less expensive limestone most waterproofing contractors use.  Limestone compacts which limits drainage.  The lime also tends to turn into cement which can clog the new drain tiles.

Landscaping

Finally, we restore the landscaping.  Do not be misled that this type of job will damage your property.  Aquamaster Drain Plumbing & Waterproofing Inc takes great effort in protecting your yard and landscaping during the process.  All equipment is run on plywood.  We bring in premium blend top soil at the finish.  We replant the shrubbery that may have been removed.   Often times it is hard to tell we were ever on your property. 

Proper waterproofing is an involved process.  Few companies accomplish this in a timely manner, with minimal damage to property, and little or no inconvenience to their customers.  Fewer yet use the best materials available.  Inferior products produce inferior results.

 

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