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How to Identify & Evaluate Freezing, Water & Other Damage to New Concrete Slabs or Foundations InspectAPedia®  -

• How to Identify & Evaluate Freezing Water & Other Damage to New Concrete Slabs or Foundations
• What are the trouble signs of freezing damage: flaking, cracking, heaving, in new concrete foundation walls, floors, slabs, footings?
• When is concrete foundation damage severe enough to need repairs?

This article describes How to Identify & Evaluate Freezing & Water Damage to New Concrete Slabs or Foundations. This website describes how to recognize and diagnose various types of foundation failure or damage, such as foundation cracks, masonry foundation crack patterns, and moving, leaning, bulging, or bowing building foundation walls.

Types of foundation cracks, crack patterns, differences in the meaning of cracks in different foundation materials, site conditions, building history, and other evidence of building movement and damage are described to assist in recognizing foundation defects and to help the inspector separate cosmetic or low-risk conditions from those likely to be important and potentially costly to repair.

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Freezing or Water Damage in Poured Concrete Slabs or Foundations

Foundation question about winter exposure: we have a new home being built and so far only the foundation has been poured and the bottom floor has been laid down. we are from Ontario Canada and it has been a bad winter with a lot of snow and ice. Our floor has been exposed to an abundance of snow, ice and rain for at least 3 months. The snow and ice has melted and then re froze. Our builder says that this is ok and it will cause no damage. Is this true? Is it ok to have the floor exposed for the whole winter? Foundation answer: If the concrete was mixed and handled properly for a cold weather pour (some suppliers use special additives to prevent freezing damage during concrete curing) and if the site was prepared and protected properly during the critical early period of curing of the concrete (protect from rain, flooding, freezing), your new foundation is probably just fine. However since things can and do go wrong in construction and in life, below we describe how to take a look at your new foundation to see if there are any early signs of trouble. Certainly if there were serious damage to a new foundation, it would be far less costly to repair it before, rather than after, framing and other subsequent steps in building construction.

While concrete continues to cure and harden for weeks or months after it has been poured, the new pour is most vulnerable to rain, frost, or water damage when the pour is very new - from the time right after the pour has been completed, for perhaps 24 to 48 hours. After that time, rain and water themselves are unlikely to damage the exposed concerete. Flaking and spalling are the two most common freezing or concrete mix (or finishing process) problems likely when a concrete poured wall or floor are brand new.

However both new or even older concrete in a poured building foundation slab or foundation walls might be damaged by water and frost from other mechanisms such as frost heaves caused by freezing wet soils which can push or even adhere-to and lift below-ground and on-ground structural components, and also settlement caused by soil subsidence due to compression (water causes compression of inadequately-compacted soil below a concrete footing or slab) or erosion (loss of soil washed out from below a concrete wall or floor).

Signs of trouble in a newly poured foundation wall, slab, or floor in cold, wet, or freezing weather

• Concrete surface flaking - is a most common visible sign of inadequate cold-weather protection of concrete during a pour. If the surface of the new pour freezes, flakes of water/concrete may pop off; if the flaking is severe, repair or replacement may be needed. If flaking is trivial/superficial only, then this is probably only a cosmetic item.
• Frost Heaves in Concrete Footings, Slabs, Floors, or Walls - cracks and/or movement in the foundation can occur due to failure to protect the new pour from freezing, combined with poor site drainage or incomplete site preparation. Either frost heave (frozen water expanding and pushing on the foundation) or settlement can occur in a new foundation, exacerbated if these conditions occur during particularly wet conditions followed by freezing weather.
• Shrinkage Cracks in Concrete Walls, Floors, Slabs - some shrinkage cracks are typical in concrete regardless of the time of year of the concrete pour, especially if control joints were omitted, but large cracks (more than 1/8" wide) or cracks which include dislocation of the concrete (one side of the crack is more than 1/8" "out" or "above" the other in a wall or floor) may deserve further evaluation. If there are many and severe shrinkage cracks in poured concrete we suspect that either the mix was improperly prepared or the pour was improperly cured. Too-rapid "drying" of concrete can increase the risk of shrinkage cracks occurring as there may be insufficient water to support the chemical curing process, hydration. So shrinkage cracks are not specifically a winter, cold weather, or rain-exposure problem in concrete.
• Concrete Surface Spalling - at any time of year, but perhaps worse when exposed to rain, if the concrete were poorly mixed in general, or lacked proper additives for cold weather use, you may see spalling (chipping off of surface areas, or soft crumbly surface areas) - spalling and bad mix can occur in any weather
• Cold pour joints in concrete walls - these are not usually a problem but might, in extreme cases, result in foundation wall leaks

Types of foundation cracks and their cause are discussed in detail at FOUNDATION CRACK EVALUATION - the direct web link to this foundation diagnosis article is http://InspectAPedia.com/structure/foundation.htm - this article that may help you recognize what's going on with your foundation.

In sum, if a month or two after a new concrete slab or wall has been poured, you don't see flaking, shrinkage cracks or movement-related cracking, then the new pour has not been damaged by freezing or wet condition. But remember that other defects: cracks, settlement, spalling, can occur later in the life of the building.

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Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

SLAB CRACK EVALUATION
  Shrinkage Cracks in Slabs
  Shrinkage Cracks Along Foundation Walls
  Shrinkage Cracks Along Foundation Walls
  Cracks at Control Joints in Concrete
  Settlement Cracks in Slabs
  Freezing & Water Damage
  Frost Heave/Expansive Soil Cracks in Slabs
  Settlement Cracks vs. Frost Heaves
  Settlement Cracks vs. Shrinkage Cracks
  How to Seal Cracks in Concrete
  Polyurethane Foam Injection
  Standards for Repair of Cracks in Floors

• "Best Practices for Concrete Sidewalk Construction," Balvant rajani, Canadian National Research Council
• "Design Considerations for Perlite Roof Slabs," a chapter in "Perlite Concrete Grade for Lightweight Concrete Construction", United Perlite Corporation
• "Quality Standards for the Professional Remodeling Industry", National Association of Home Builders Remodelers Council, NAHB Research Foundation, 1987. See our books at "Structure" at the InspectAPedia Bookstore
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