Restoration Education

The Importance of Preventive Maintenance of Structural Concrete Elements

In this beautiful State of ours we would all like a view of the water, and that can sometimes come at a price. In the case of a coastal condominium, the price not only includes initial acquisition of the waterfront location, but also involves great diligence on the part of the condominium community’s Board of Directors and Property Manager in terms of determining the requirements and budgeting, for preventive maintenance. We've all heard the proverb “an ounce of prevention is worth a pound of cure”. Prevention starts with a waterproof membrane to minimize moisture penetration into your concrete walkways, balconies, lanais and parking structures. Such a coating, along with regularly scheduled condition inspections, will serve to greatly reduce or prevent the very significant costs associated with a major concrete restoration project. Or, in extreme cases, complete replacement of those deteriorated, exposed concrete elements.

For those of us who have been in the industry for a couple of decades or more, we can recall when developers began to realize that using carpet on exterior walkway, balcony and lanai areas had not only fallen out of fashion, but added to the concern for protecting these exposed concrete elements. The moisture produced by rains, fog, mist, and wind-blown salt spray would soak into the carpeting and remain on the deck surfaces much longer, allowing more opportunity for it to penetrate into the concrete and put into motion corrosion/rusting of the structural steel ‘skeleton’ of the building. This can also be true of finishing with tile without a waterproofing membrane in place. The principle catalyst to the rusting process is dihydrogen oxide (better known as water). The hydrogen atoms within the water penetrate the microscopic pockets and cracks of the exposed steel, and when combined with other elements will form acids which progressively exacerbate the corrosion process. Oxygen atoms will combine with the metallic atoms and a corrosive oxide compound will occur causing the steel to expand, further exposing the steel to destructive elements. The process will occur faster if sodium is present (as in the case of salt water). This “cancer cocktail” will embrittle and weaken the structural strength of the steel. This in turn leads to cracks being created in the concrete surfaces, which exponentially accelerates the corrosion and spalling process.

Preventive maintenance can come by way of installation of one of the various protective coatings available today. To mention but a few alternatives that will help reduce the potential of significant concrete damage (and resulting expenses in the long run), there are highly flexible basic and decorative urethane coatings; “hybrid” systems consisting of flexible urethane bases and durable cementitious finishes, and there are both cementitious and flexible membranes that can be installed beneath ceramic tile surfaces. We can point to several communities in Southwest Florida to whom we have strongly recommended one of these protective membrane solutions, (as did their Engineers), but the management elected to defer a decision. Major concrete restoration and the attendant expenses, loss of potential rental incomes, and substantial inconvenience to the owners became a reality for those who owned a unit within those communities, as well as members of the Board when some year’s later total replacement of the compromised concrete had become the only answer. In addition to the General Contractor’s cost of repairs, these types of projects will typically have engineering expenses for investigation, development of a defined scope of work, and monitoring of the work. Depending on the depth of repairs required, these projects can involve many months of planning, bidding, permits (which is often a tedious process), and re-construction. The project can often involve access restrictions to most units’ common and limited common elements as a safety concern, as well as invasive, noisy and unpleasant demolition and removal of debris from the damaged elements, placement of new or supplemental reinforcing steel (in most conditions), placement of new ready-mixed concrete or quite possibly bag mixes of repair materials for smaller or more difficult-to-access areas, design and installation of new aluminum handrails or screen cages, new stucco finishes, new vertical wall waterproofing or paint product application, and ultimately, a new waterproof membrane to insure this process will NOT be required again any time soon.

We recently completed a project which is an interesting example of the benefits of waterproofing. This Siesta Key property is a 40 year old structure located on the beach that ten years ago performed a major restoration project, undertaking extensive concrete repairs on its walkways and balconies. The intended scope of work for our current project included removal of wall coatings, painting, minor concrete restoration, waterproofing walkways, and installation of tile on the walkways. However, what we found upon removal of the existing decorative coating on the walkways was such severe corrosion of the structure that complete removal and replacement of the walkway slabs was necessary due to what has been determined as the absence of waterproofing on the walkways. The corrosion of the slab structures was so severe that conventional repair methods were futile, requiring a complete shut down of the building in order to perform this work. In addition to the extra cost of repairs, this is a high rental property that lost considerable income, and a few owners have even been displaced from their homes.

In stark contrast to the building's walkways is the condition of the balconies on the beach side. Very limited repairs have been required on the slab edges with exception to one balcony stack--the only stack that had not previously received a waterproof coating during the previous restoration project! This particular project is one of many that provides supporting evidence of the significant value of waterproofing your concrete walkways, balconies and lanais and the consequences of not doing so. Southwest Florida truly is paradise, but even paradise requires a little preventative maintenance to ensure we all get the best of what our communities have to offer.