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While concrete is known for its long-lasting properties, over time concrete structures can experience damage or deterioration. At that point, the owner must determine whether to demolish or restore the building.

Deciding factors

Several stakeholders are usually involved in the start over or repair decision. "It would be a consultation among the building owner, the facility manager and appropriate engineers and architects," says Todd Miller, product line manager at Mapei. "Factors include structural integrity, the desired use and aesthetic of the structure and the cost analysis."

That analysis must include not only the cost of demolition and rebuilding, but also the loss of rent or other income from the structure during the construction process, such as a parking garage.

"If the owner has a building or a complex of buildings that is dependent on a parking structure and he has no place to build a new one, he usually wants to restore it and keep part of it in service during the restoration," explains Ralph Brown, vice president of National Restoration Systems Inc., an award-winning repair and demolition firm. "Some of these parking structures are pay structures where people pay fees to park. If they close the structure, they lose the customer. There's no assurance these customers will come back if they build a new structure at a later date." Financial concerns may result in partial demolition followed by restoration.

Another common partial demolition followed by repair is done on floors in commercial establishments. "They might start with removal of the existing finished floor down to the concrete substrate," Miller says. "They may then cut trenches in the existing substrate to provide for new plumbing lines or electrical routing. Those trenches would need to be filled and the complete substrate refinished with a suitable, wearable topping."