Alchatek Blog

I recently had the opportunity to train a crew on a very interesting job inside an underwater utility tunnel beneath a lock and dam in the St. Lawrence Seaway. This seaway connects the Great Lakes to the Atlantic Ocean. This tunnel is underneath a giant concrete deck, so the walls have taken a lot of pressure over time. The soil also shifts and settles underneath the tunnel as the years go by. Those factors, in addition to freeze/thaw cycles have caused cracks to appear in the walls.

One particularly large crack was 20 feet long and up to 2 inches wide in some places. The water leaking through created an especially dangerous situation considering the 480 volt electrical box you can see in the photo above. There is also plenty of valuable equipment in the tunnel that is susceptible to water damage.

I suggested to the customer that they buy about four 5 gallon pails of Spetec F400. I recommended this material because it works very well in wet joints and cracks. It also remains somewhat flexible after installation, so if the walls settle or shift a little more, the cured grout will not break. When I showed up we got to work immediately with our on-the-job training, using modified airless sprayers to pump the material.  Overall, it took about 2.5 hours for the crew to get the job done while learning the leak seal process at the same time.

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Curtain wall grouting is a leak seal method that is often required when cracks cannot be identified, when walls are made of material that does not respond well to crack injection (such as masonry, stone and CMU), and when previous leak seal methods have failed.  

Curtain wall grouting is the process of injecting water reactive resin behind the leaking wall in a widespread grid pattern. The water on the other side mixes with the grout and cures to a solid mass covering the surface of the wall on the other side. In addition, you don’t have water pressure dislodging external “patches” over time, as can be the case with other methods. This procedure is best done with either AP Fill 700, Spetec H100 or one of the Spetec AG100 - 300 series of acrylate grouts.

These expansive one-component polyurethane resins can be injected through the wall to cut off large flow and high pressure water leaks. The resins react with the water on the other side to form a long lasting, durable seal. AP Fill 700 has a high rate of expansion and a little flexibility. Spetec H100 has a lower rate of expansion but a bit more flexibility. The Spetec AG 100 - 300 series has a very low rate of expansion (only a slight swelling) but a lot of flexibility. 

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When it comes to floor and wall joint leak repairs, there are usually two scenarios to consider. These repair jobs usually come about because of leakage where the floor and wall typically meet. Each scenario determines where drill points should be placed for repair procedures using polyurethane.

Scenario 1:

In this scenario the floor has been poured first before a wall is made to confine a space. To fix leaks that occur in this type of joint, a hole is drilled at the bottom of the wall. This is usually about 6-8 inches above the floor and at a 45 degree angle. Once drilled, soaked oakum is then placed in the hole. Once cured, the oakum serves as a gasket and initial leak seal. Polyurethane grout is then pumped into the hole for a deeper seal, while the oakum gasket prevents it from spilling back out.

Scenario 2:

In this scenario the wall has been poured first before the floor. The hole is drilled on the floor about 6-8 inches from the wall and at a 45 degree angle. Soaked oakum is placed into the hole to create an initial seal and gasket. Polyurethane grout then injected behind it for a thorough leak seal solution.

Materials often used for these applications:

AP Oakum: for creating gaskets

AP Fill 700: for drilled holes that are about 2 inches wide

Spetec F400: for drilled holes that are between ½ and 1 inch wide

AP Seal 500: for tight joints with multiple hairline cracks

Spetec F1000: works well if curtain grouting is needed to drill through brick walls

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The terms hydrophobic and hydrophilic may not mean anything to the average person. But, to a contractor, these terms can mean a world of a difference. Hydro means water while phobic means “to fear” and philic means “to love”.  Alchemy-Spetec offers both hydrophobic and hydrophilic polyurethanes, so it is important to be aware of the differences between the two types.  

Hydrophobic Polyurethanes

Hydrophobic polyurethanes naturally repel water (similar to the way oil would repel water and stay separate if you were trying to mix them in a glass). These products push water out of the area in question as they expand. Hydrophobics are used with catalysts which allow you to adjust the set time. They also have zero shrinkage after curing.

Check out these hydrophobic polyurethanes:

• AP Fill 700
• Spetec F400
• Spetec F1000
• Spetec H100 
• Spetec H40 
• AP Lift 475
• AP Lift 440
• AP Lift 430
• AP Soil 600 

Hydrophilic Polyurethanes

Hydrophilic polyurethanes naturally mix with water before curing (similar to the way gin and tonic mix thoroughly in a glass). This characteristic allows for a very strong chemical and mechanical bond, as water helps pull the material into the pores of the concrete. These products do not require a catalyst. You can pump them straight out of the pail.

Check out these hydrophilic polyurethanes:

• AP Seal 500
• Spetec GT350

Don't Oversimplify These Concepts

Don't get caught in the trap of oversimplifying hydrophilic vs. hydrophobic.  There are varying degrees of each (see chart below for more information on how this is measured) .  

Some hydrophilic materials will keep absorbing water (10-15 times their original volume).  Others (such as our AP Seal 500) only absorb as much water as is necessary for their reaction and then they reject the rest.  Yes, hydrophilic gels will shrink like crazy in the absence of water, but the AP Seal 500 won't.  It is completely safe to use in a dry environment.

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Continuing with this week's essential blog post roundup, let's review the best of recent leak seal articles. First we have a profile of a tunnel patching job with Spetec GT350. Next we have an overview of common residential leak seal opportunities. Finally, we'll leave you with a post on sealing pipe penetrations. Hopefully these three posts will get you thinking about leak seal job possibilities for your business.

Northgate Link Extension with GT350

By Thad Brown

In Seattle, Washington there has been construction taking place in the region’s most congested traffic area. The Northgate Link tunnel is being extended to connect the Northgate, Roosevelt and U District neighborhood transit stations to downtown Seattle and the airport. One of our contractor customers has been an ongoing asset to this project as they have been patching the tunnel walls while during the construction process.

Click here to read more...

Waterproofing Residential Spaces

By Anthony Sandone

The residential waterproofing market is huge and can be quite the cash cow for contractors who enjoy tending to a constant stream of smaller jobs. Let's review common residential waterproofing issues and the Alchemy-Spetec products you can use to address them.

Click here to read more...

Sealing Pipe Penetrations

By Thad Brown

Over the years, I have been asked countless times for the best way to seal pipe penetrations and other irregular annular spaces. Pipe penetration scenarios often have to do with water supply lines, electrical conduits and gas lines just to name a few. The main concern is creating a durable watertight seal between the outside of the pipe and the structure the pipe is penetrating through.

Click here to read more...

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Alternately, oakum can be soaked in Alchemy Spetec leak sealing resins first, and then packed into leaking cracks and joints.  There the resin impregnated oakum will react with the water and expand to form a dense, yet flexible seal.  This seal will also keep contained, any resin that is injected behind, allowing for the injected material to stay in the crack or joint where it is intended to be.

Click here to read the Oakum Datasheet.

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Acrylates were introduced in the early 80s to the waterproofing industry as a less toxic alternative to acrylamide for repairing structures. Acrylamides are sold in powder form, while acrylates come ready for use in a liquid form.

Acrylate grouts are used to stabilize soil, seal leaks in concrete and brick walls, repair joints in sanitary sewer pipe laterals, and repair rock fissures. Due to their low viscosity ratings, these acrylates can be used in a variety of applications such as industrial, commercial, and municipal.

Here is a general overview of Alchemy-Spetec acrylate grouts:

Spetec AG100

• Ideal for municipal applications.
• Repair joints in sanitary sewer pipe laterals.
• Curtain grouting and soil stabilization.
• 20 cps mixed viscosity.

Spetec AG200

• Consolidate soil and prevent erosion around floors, walls, etc.
• Curtain grouting and soil stabilization.
• Crack injection.
• 40 cps mixed viscosity.

Want more information on acrylate grouts and other leak seal products?

I have been in a number of elevator pits harboring around two feet of water due to water leaks. These pits are usually at or below the water table, underneath the first floor of buildings with concrete poured around them. Over time the water tables rise and fall due to seasonal changes. This causes the soil to move, creating problems in the structure. These leaks are common in commercial buildings, especially if the elevators are not properly maintained.

There are several reasons why these elevator pits spring leaks and cause problems.

One of the main causes of these leaks is faulty waterproofing that was incorrectly installed during the construction phase. This allows joints that go around the elevator pit to leak due to imperfections or cracks in the base or walls. Another cause is simply time itself. As the elevator pit ages, the waterproofing system in place naturally begins to fail. The outside membranes begin to break down and negatively affect the performance of the waterproofing system.

What Can You Do?

The solution depends on the type of structure. You're usually looking at either poured concrete walls, block walls or brick walls.

Poured Concrete Walls

In the case of concrete walls, water will seep through by way of cracks. You can counteract this problem by crack injecting with Alchemy-Spetec’s Spetec F400 or AP Seal 500. They both work well in wet conditions and are water reactive.

Block and Brick Walls

In the case of both block and brick walls, movement in the soil due to water table changes can move the individual blocks or bricks - causing gaps to occur. These gaps result in issues like leaking floor/wall joints and border joint leakage/decay. You can counteract these problems by injecting grout through the wall into the outside soil (a process called curtain wall grouting) with Alchemy-Spetec’s AP Fill 700 or Spetec H100.

All of these products can also be used as part of preventative measures during the construction phase.

Want more information on sealing leaks with Alchemy-Spetec products?

The past few months have been a little hectic in the upper west side of the country lately. In Seattle, Washington there has been construction taking place in the region’s most congested traffic area. The Northgate Link tunnel is being extended to connect the Northgate, Roosevelt and U District neighborhood transit stations to downtown Seattle and the airport.

One of our contractor customers has been an ongoing asset to this project as they have been patching the tunnel walls while the construction of these links have been in progress. They've also been patching cross hatches (the short passage way between two sections of tunnel). The main product being used for these projects happens to be Alchemy-Spetec's GT350.

Click here to read our previous blog post on GT350.

This particular polyurethane resin is ideal for waterproofing and shutting off water leaks permanently.
Want more information on Alchemy-Spetec leak seal products?

The residential waterproofing market is huge and can be quite the cash cow for contractors who enjoy tending to a constant stream of smaller jobs. Let's review common residential waterproofing issues and the Alchemy-Spetec products you can use to address them.

Leaks - Concrete Walls

This is the most common problem in the residential market, most often found in basements. You can repair leaks in poured concrete and pre-cast walls with Alchemy-Spetec’s F400. This hydrophobic grout will not shrink after application, during spells of dryer weather. In addition, this product has a thin composition and can penetrate fine, hairline cracks. The application process involves injecting the cracks with the resin, which then reacts with the leaking water to form a durable watertight seal. 

Leaks - Non-Concrete Walls

Many basement walls are made of brick, block, stone or rubble. Leaks in these types of walls require a process called curtain wall grouting (a.k.a. “through-wall” grouting). Curtain wall grouting involves drilling holes in a grid pattern and injecting Alchemy-Spetec’s AP 700 through the wall to form a waterproof curtain on the other side.

Leaks - Floor/Wall Intersection

Sometimes builders will neglect to use a leak seal product at this critical joint in the structure where the floor and wall meet. Even if they do seal these joints initially, with a mediocre product there will be failure over time. When faced with these types of issues, you can inject F400 for a lasting, durable repair. This application process is similar to crack injection for leaks in concrete walls as described above.

For more details on these application methods, click here for my blog series on Crack Injection and Curtain Wall Grouting.

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