Below-Grade Foundation Waterproofing

WHITE CAP

Course 24, Level 2

Below-Grade Foundation Waterproofing

Slide 1: Welcome

Thank you for your interest in Below-Grade Foundation Waterproofing. This is a Level 2 course. To have gained access to this course, associates must have completed the Level 1 prerequisite course, Concrete Foundation Basics.

The associate who successfully completes this course will understand the basic properties and installation of the products used to waterproof cast-in-place concrete foundations below grade.

The course will focus on the most common types of waterproofing products and accessory components and discuss methods and materials used in the transition from below grade to above grade in the foundation assembly. The course will also address safety concerns associated with waterproofing below-grade foundations. White Cap is a major supplier of below-grade foundation waterproofing products and accessory components.

Slide 2: Features

Before we begin, let us point out a few features.

On the left, you’ll see two tabs. Use the Notes tab to follow this narration. Click on the Menu tab to track your progress. You can click on a section or page to navigate back to it.

On the top right, you’ll see Ask A Question, Resources, and Exit. Click on Ask A Question to offer comments or ask questions. Click on Resources to download the script and additional resources. Click on Exit to leave at any time. Your progress through the course will be saved. When you open the course again, you’ll start at the slide you last completed.

On the bottom, there are two buttons: the Previous and Next buttons. Use the Next button to advance to the next page. Use the Previous button to go back to a previous page.

Click the Next button to advance to the next page.

Slide 3: Recommended Connection

To ensure a successful online connection while you complete this course, we recommend the following:

Use a recommended Web browser: Microsoft Internet Explorer 7 or Microsoft Internet Explorer 8.
Use a wired broadband connection.
Keep ALL windows associated with the course open. If a window opens in your browser as you’re starting the course, leave it open.
Close all other programs.

Slide 4: Course Progress

PLEASE NOTE: This program tracks your course progress so that you can save your session and return at a later time. If you are presented with an error message while completing or exiting the course, please email .

Slide 5: Course Agenda

This course is separated intofoursections: Foundation Waterproofing Essentials, Waterproofing Materials and Methods, Foundation Waterproofing Details and Installation and Safety. We recommend that you take notes while viewing this presentation to help you retain the information presented.

After each section, there will be a short learning check, or assessment. You’ll have to pass the assessment before advancing to the next section.

Slide 6: Learning Objectives

After completing this course, you will be able to explain the purpose and various types of waterproofing used with below-grade concrete foundations.You will also know the various accessory components and tools required by waterproofing assemblies, as well as primary safety considerations when working with waterproofing products and below-grade foundation systems.

By the end of this course, you will understand:

The purpose for and terminology associated with concrete foundation waterproofing.
The most common methods of preventing moisture infiltration into concrete foundations.
The accessory components necessary to detail a foundation waterproofing assembly and the methods used to mediate the foundation’s transition from below grade to abovegrade.
Considerations involved in the installation of foundation waterproofing assemblies, including proper safety measures.

SECTION 1: Foundation Waterproofing Essentials

Slide 7

Section 1 will describe the purpose of waterproofing concrete foundations and explain the relevant terminology necessary to discuss waterproofing products and applications.

Slide 8

The stability of a structure begins at its foundation, which transfers structural and live loads from the building to the ground. One the greatest vulnerabilities that concrete foundations face is moisture in the form of groundwater or wet soil.

Furthermore, typical untreated concrete is a porous material. Over time, water can penetrate the surface of exposed concreteand eventually infiltrate the building interior. Once inside, water can cause damage to interior furnishings and finishes and increase the risk of mold growth. If the water that is absorbed into the concrete contains corrosive chemicals, such as salts, the concrete’s steel reinforcement assemblies may be compromised, degrading the structural performance of the concrete component.

Given concrete’s properties and moisture’s effects, waterproofing concrete foundations is an essential part of the construction process. Effective waterproofing requires two important measures: 1) surface treatments that will restrict the foundation’s ability to absorb moisture; and 2) drainage to move moisture away from the concrete surface, reducing the amount of hydrostatic pressure on the foundation.

Slide 9

The pressure exerted by standing water is known as hydrostatic pressure. Hydrostatic pressure may be exerted by the water table or by poorly-drained soil.

Water in the ground will exert pressure on a foundation wall assembly built below grade level. If the wall is untreated, moisture infiltrationwill result. Slab-on-grade concrete foundations are also at risk of water infiltration since they will absorb moisture from standing water or wet soil underneath the slab.

Relieving or reducing the effects of hydrostatic pressure is the primary purpose of below-grade foundation waterproofing.

Slide 10

Technical standards organization ASTM International defines waterproofing as the treatment of a surface to prevent the passage of liquid water in the presence of hydrostatic pressure.

By comparison, damp-proofing is defined as the treatment of a surface to retard the absorption of moisture in the absence of hydrostatic pressure.

In other words, damp-proofing will help prevent some water from infiltrating a concrete foundation assembly, but not all. By contrast, properly applied waterproofing will limit all water infiltration.

Slide 11

Waterproofing products should be selected carefully based on site conditions, climate and construction type. Incorrect selection or application of waterproofing may result in excessive moisture build-up on interior surfaces and the growth of mold and mildew.

Earthwork processes such as grading and backfilling are also important to creating the proper drainage conditions that will prevent water-related damage. Cracks in the foundation, cracks in the vertical façade system above a foundation or unequal settlement of soil around the foundation assembly can be evidence of poorly draining soil due to improper backfill practices below grade or improper finish grading around the building.

Slide 12: Section 1 Summary

This section:

•Explained the purpose of foundation waterproofing

•Introduced the relevant terminology required to discuss waterproofing processes and products

•Discussed hydrostatic pressure and the difference between dampproofing and waterproofing, and

•Covered some common problems that stem from a lack of waterproofing or poorly applied waterproofing

Slide 13: Section 1 Assessment

This short assessment will test your knowledge of the purpose of waterproofing below-grade foundation systems and relevant terminology. You must correctly answer at least six of the eight questions to advance to Section 2. You will receive feedback after answering each question.

If you do not pass on your first attempt, that’s OK. You will be directed to the beginning of the section where you can review the concepts before re-attempting the assessment. Click Next to begin.

SECTION 2: Waterproofing Materials and Methods

Slide 14

Section 2 will cover the most common methods of preventing moisture infiltration into concrete foundations, including the types of products involved and their application.

Slide 15

Prolonged exposure to hydrostatic pressure can exert more force than a typical foundation wall’s structural assembly is meant to resist. Over time, the pressure can cause cracks or other structural breaks in the concrete of the foundation wall assembly, leading to significant water leaks.

The primary purpose of drainage is to reduce hydrostatic pressure to the lowest possible level. When used in conjunction with a dampproofing or waterproofing treatment applied to the concrete foundation surface, drainage systems provide an effective and efficient solution for protecting against water infiltration.

Drainage can be achieved through several different means, all of which work by providing excess water with an easy path of travel. By prescribing the medium and direction of that path, drainage effectively carries water away from the foundation, reducing hydrostatic pressure and its associated problems.

After directing water away from the foundation, all drainage systems must channel water to a code-approved outlet, typically a storm sewer system, sump pump system or daylight.

Slide 16

Traditionally, drainage has been provided by a stone backfill and foundation drain system. In this system, a perforated drain pipe at least four inches in diameter is laid into a bed of gravel at the level of the footer, then covered with more gravel and a layer of filter fabric. The area above is then filled with gravel up to a few inches below grade. Another layer of filter fabric is applied on top of this stone backfill then topped with soil to allow for plantings at grade level.

The gravel backfill provides water with a quick and easy route to the foundation drain assembly, which carries the water a suitable distance away from the foundation to an approved outlet. The filter fabric prevents soil from washing into, and thus obstructing, the drainage material.

The foundation drain remains a common component in below-grade foundation waterproofing assemblies today. However modern technologies have led to products that are replacing the stone backfill.

Slide 17

Drainage mats represent a common alternative to the traditional stone backfill. Usually consisting of a layered system of filter fabric and drainage core, drainage mats are applied directly to the outside of the concrete foundation. Groundwater from the adjacent soil travels through the filter fabric into the drainage core.

The drainage core has a much higher flow capacity than gravel backfill, thus providing a more efficient method to quickly remove excess water from around the foundation. The water in the core is expelled into a foundation drain or perimeter drain at the level of the footing. The drain then carries the water to an approved outlet.

Slide 18

An alternative to stone foundation drain systems is the high-capacity strip drain. Similar to drainage mats but fabricated in long strips manufactured in rolls instead of mats, strip drains consist of a drainage core protected by filter fabric. Installed in shallow trenches, against the bottom edge of foundation walls or the underside edge of a concrete slab, the strip drains carry water quickly and efficiently away from the foundation. In some applications, the strip drain eliminates the need for gravel. The strip drain will connect at its end or locations along the perimeter to strip drain end connectors and black drainage pipe or PVC pipe to carry the water to an approved outlet. White Cap is a supplier of drainage mats and strip drains.

Slide 19:

Installation methods for dampproofing products include the following:

•Asphalt emulsions can be applied with a hand trowel, brush or heavy duty spray equipment, depending on the viscosity.

•Elastomeric fluid-applied membranes can be applied with a brush or roller, hand trowel or spray gun, depending on the viscosity.

•Crystalline products can be mixed into the concrete before it is poured or applied to the finished concrete surface.

•Liquid waterproofing can be applied with a spray gun, a brush or roller.

•Waterproofing sheets are applied either mechanically or with an adhesive to the foundation’s exterior surface.

•Bentonite clay is usually encased between two layers of woven and non-woven, puncture-resistant polypropylene fabric designed for use under reinforced concrete slabs. It is installed over a properly prepared substrate with the non-woven geotextile side up and overlapped at adjoining edges.

Slide 20: Section 2 Summary

This section covered:

•The primary components in waterproofing below-grade concrete foundation assemblies

•The purpose and various types of drainage systems

•The relevant applications for, as well as limitations of, dampproofing

•The most common types of waterproofing systems, from liquid applied to sheet applied

•The growing popularity of the integrated approach offered by building envelope systems, and

•Dampproofing installation methods

Slide 21: Section 2 Assessment

This short assessment will test your knowledge of below-grade waterproofing systems and products. You must correctly answer at least eight of the 10 questions to advance to Section 3. You will receive feedback after answering each question.

If you do not pass on your first attempt, that’s OK. You will be directed to the beginning of the section where you can review the concepts before re-attempting the assessment. Click Next to begin.

SECTION 3: Foundation Waterproofing Details

Slide 22

Section 3 will discuss several of the most common accessory components used with waterproofing treatments and drainage to properly protect a below-grade concrete foundation against water infiltration. Several of these components help mitigate the transition from the foundation system below grade to the parts of the building envelope above grade. Others offer secondary and even tertiary barriers to the passage of water across vulnerable points in the concrete foundation like joints. White Cap stocks a number of these accessory components.

Slide 24: Flashing – Tab Interaction

Flashing is often used as the first line of defense above joints that are susceptible to water infiltration and to help the building system shed water properly. Flashing is a thin, continuous sheet used to prevent the passage of water through a joint in the building envelope. Flashing can be made of metal, plastic, rubber or even waterproof paper. Click on the grey tabs on the left or click the gold arrow in the upper right corner to hear about different types of flashing.

Drip Edges

Drip edges are a type of flashing that forces water to fall free of the building rather than be pulled back toward the building by surface tension. They are commonly used at the edges of horizontal foundation surfaces, as well as in certain masonry wall applications.

Counter Flashing

Counter flashing collects water from above, ensuring that it drains onto the top surface of, rather than behind, the waterproofing components below it.

Base Flashing

Base flashing is a method, often applied at the bottom of a foundation, which seals the transition between horizontal and vertical surfaces, such as the transition from a wall to the horizontal surface of a foundation assembly.

Slide 24: Sealing Foundation Penetrations – Tab Interaction

Sewer pipes, water lines, drain basins in the floor slab and sleeves for electrical, gas or communications create penetrations in the foundation assembly. When not properly treated, these penetrations provide an easy point of entry for water into the wall. The water may also flow behind the waterproofing membrane if a lateral path presents itself at this opening.

Please note that the narration will provide additional information to the text that is presented on the screen. This additional information is available to download by using the Attachments link at the top right. Click on the grey tabs on the left or click the gold arrow in the upper right corner to hear about different ways to seal foundation penetrations.

Fluid-Applied Waterproofing

Fluid-applied waterproofing is an easy solution to sealing around pipes and conduits. Because it’s flexible, the liquid waterproofing can handle the expansion and contraction that some pipes may undergo due to temperature fluctuations.

Sheet-Applied Products

Sheet-applied products are also sometimes used to seal around these openings. A piece of sheeting is cut to fit around the pipe then secured in place with a heat weld.

Protective Plates

Protective plates, also referred to as escutcheons, that affix to the wall and fit tightly around the pipe, are another common solution, as are mastic sealants and specialized tapes.

Waterstops

Waterstops are a common product used to waterproof many types of construction joints. Made of rubber, synthetic material or a joint compound containing bentonite, waterstops prevent the passage of water through vertical to horizontal joints, like those found at the transition from foundation wall to footer, and expansion joints.

Composite Waterstops

For non-moving joints like that between foundation wall and footer, a composite waterstop, such as a joint compound that contains bentonite, will effectively prevent the passage of water through the joint. These waterstops are embedded in the concrete, installed on the edge of one concrete pour before the adjacent concrete is poured.

Embedded Waterstops

Other joints in concrete foundation walls and slabs are designed to allow for movement. For example, expansion joints are built into concrete construction to allow for the natural expansion and contraction of concrete due to temperature changes. At these joints, a waterstop must be embeddedinto the adjacent concrete components. The waterstop creates a diaphragm along the seam that is flexible enough to expand and compress while blocking water penetration through the joint. Click the gold “Next Slide” button in the upper right corner to advance.

Slide 25: Sealing Sheet-Applied Waterproofing – Tab Interaction

The edges and seams of sheet-applied waterproofing must be properly treated and secured to ensure that water cannot get behind the membranes.