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How to Ensure Waterproof Concrete Foundations

Asking the right questions in a pre-construction meeting can lead to a quality placement.

Rick Yelton

February 2, 2024

2 Min Read
Alamy

When a committee of concrete contractors and ready-mixed concrete producers developed the  NRMCA/ASCC Checklist for Concrete Pre-Construction Conference more than 25 years ago, concerns for waterproofing were often an afterthought to placement. In WOC360’s Waterproofing a Concrete Foundation webinar, posted in December 2023, our experts, Jeff Bowman and Brent Anderson, suggested that producers and contractors in today's construction environment discuss waterproofing details in the pre-construction meeting. 

Greater attention to prevention

According to a 2022 article in the Journal of the American Institute of Architects, 70 percent of construction defect cases are caused by water intrusion. While most of the cases identified in the report involved roofs and walls, researchers also cited foundations as an area of concern for water troubles.

There are three reasons why attention to improving waterproofing foundations is increasing. Many new construction sites are located in poor soils or flood plains. New urban building foundations are below water tables, subjecting them to increased water pressure. And many jurisdictions have adopted interior air quality standards focusing on creating healthier structures.

Pre-construction meeting discussion items

Our experts proposed these checklist topics contractors should address with the general contractor and design professional in the discussions leading up to the placement.

  • Start with the mix design; consider adding a small pre-pour mock-up to judge the mix's workability.

  • Review the structural plans to control cracking, often opting for closer control joints.

  • Discuss how the contractor plans to protect the concrete after the forms are stripped; today's performance mixes are often leaner, which requires closer attention to curing as the concrete hardens.

  • Review consolidation procedures to avoid any honeycombing and other surface defects.

  • Discuss what type of waterproofing treatment is specified; the waterproofing manufacturer may have requirements regarding wall surface smoothness. 

  • Discuss the type of foundation wall surface quality required; many waterproofing materials require a very smooth surface, requiring the concrete contractor to ground down projections or fill in surface voids. 

  • Review the construction schedule to allow adequate time for the waterproofing contractor to inspect before beginning treatment. 

  • Discuss the who, how, and when the finished wall's moisture content will be measured, as many waterproofing treatment manufacturers specify this requirement. 

  • Coordinate the backfilling procedures concerning technique and timing.

Resources mentioned in the webinar

ACI 546.3R-14 Guide to Materials Selection for Concrete Repair

ACI 515.3R-20 Guide for Assessment and Surface Preparation for the Application of Protective Systems for Concrete

Sealants: The Professional's Guide, published by the Sealant, Waterproofing and Restoration Institute

Technical Bulletins, published by the Sealant, Waterproofing and Restoration Institute

You can view WOC360’s Waterproofing a Concrete Foundation webinar on demand.

About the Author(s)

Rick Yelton

Editor at Large, World of Concrete

Rick Yelton is the Editor at Large for World of Concrete, an Informa Market’s event. Rick is an engineer who has been involved in the concrete construction industry for more than 3 decades

Rick is an active member of several ASTM International technical committees for cement, concrete and masonry. He has served on the Executive Committee of the Concrete and Concrete Aggregates - C09. He is the current chairman of subcommittee C09-22 Materials Applied to Fresh Concrete.

Rick is also active on several technical committees at the American Concrete Institute.

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