July 1998 Table of Contents

Features Spray-Applied Membranes Keep Basements Dry

In the past decade, the use of spray-applied waterproofing membranes--materials tough enough to withstand hydrostatic pressure and elastic enough to bridge hairline cracks in a foundation wall--has helped foundation contractors boost the value of their services, as well as their bottom line. Read more

Features Do Driveways Right the First Time

By following the simple guidelines presented here, contractors can avoid the most common driveway flaws that homeowners complain about: scaling, cracking and discoloration. Read more

Features Controlling Curling and Cracking in Floors to Receive Coverings

Because of an increasing number of moisture-related floor-covering failures in the past several years, some designers now recommend eliminating the granular blotter layer that's often used between the concrete and the vapor retarder or vapor barrier. Though a blotter layer offers several advantages, it can hold water from many possible sources and cause problems if the floor will receive moisture-sensitive coverings such as sheet vinyl, rubber, wood or similar materials. Read more

Features Rules for Backfilling With a Backhoe Bucket

Don't use the side of a backhoe-loader bucket to push material back into an excavation, say backhoe manufacturers. Backfilling using the swing circuit and dragging the bucket sideways can damage the dipperstick, boom, swing cylinders or mainframe of the machine. Read more

Features Smoothing Floors With Gypsum Underlayments

Designed to flow easily and cover evenly, self-leveling floor underlayments are a practical, economical way to smooth and level concrete or plywood subfloors, making them ready for the application of floor coverings. The underlayments are poured or pumped onto the subfloor and are self-smoothing so no troweling is needed. Most of the products simply require spreading with a screed, float or other tool. Read more

Features Meeting Design Requirements for ICF Homes

Because building codes specifically addressing the use of insulating concrete forms for residential construction don't yet exist, builders of ICF homes should be aware of current code requirements and how to meet them -- particularly those for fire resistance, termite protection, moisture control, seismic resistance and wind resistance. Read more

Features Repair at O'Hare

Chicago's O'Hare International Airport is home to the largest parking structure under one roof, accommodating six 545,000-square-foot levels and 8,800 parking spaces. Built in 1972, the garage recently underwent $46 million of repairs to extend its service life. Read more

Problem Clinic Can an Admixture Replace a Vapor Barrier?

Our finishers complain whenever we're required to place concrete directly on a vapor barrier. The concrete bleeds longer, delaying finishing, and seems more likely to crack. We've been told we can solve this problem by ordering concrete with an admixture Read more

Problem Clinic Parking-Lot Spalling Problem

We built a very large parking area for an industrial plant and installed contraction joints but no expansion joints. Read more

Problem Clinic Using a Self-Propelled Screed on a Post-Tensioned Floor

Can I safely use a self-propelled, laser-controlled screed to strike off concrete for a post-tensioned floor without damaging the post-tensioning cables? Read more

Problem Clinic Placement Method for Expansive-Cement Concrete

We're placing our first bridge deck with shrinkage-compensating concrete using Type K expansive cement. We normally use a crane and bucket for bridge decks but wonder if this is the best placement method for shrinkage-compensating concrete. Read more

Problem Clinic Avoiding Polyurethane Grouting Pitfalls

We've had much success using polyurethane grouting to stop active leaks through concrete cracks and joints. Read more

Problem Clinic Repairing Dry-Shake Hardener Delaminations

We recently installed a 26,000-square-foot slab-on-grade that had a colored dry-shake hardener applied at a rate of 2 pounds per square foot. We have experienced numerous spots of delamination. We are beyond discussing the cause and are trying to arrive a Read more

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