Take It from the Top
Starting from the top, the roof is an obvious culprit in allowing water to penetrate the building envelope causing not just damage to interior finishes and personal belongings but also serious structural problems and indoor air health issues. For this reason, all roof surfaces should be inspected at least once a year or after any wind event of 50 miles per hour. Flat or low-slope roof structures are surfaced typically with EPDM rubber membrane or vinyl sheet material. These materials with useful lives of 25 years and more rarely fail, rather it is their junctures such as adhered seams and connections to other materials such as flashing where water infiltration starts. Keeping internal and external drains and scuppers free of debris are also key inspection points. High-slope roofs surfaces with asphalt shingles are similar in that the inspection focus should be on suitable flashing and proper gutters and downspouts.
Down Below
Below the roof are the various exterior facades found on condo buildings having many similar issues. Almost all facades allow some penetration of moisture. The issue is how to control this water infiltration. Normally this is done with drainage planes behind the façade material. Masonry and concrete facades as well as vinyl and stucco siding allow the penetrating water to escape via weep holes strategically placed to vent steam and moisture. Often the biggest mistake made in building maintenance is an attempt to seal the façade surface only resulting in blocking the façade’s designed drainage system or trapping moisture inside the façade material thus preventing natural drying. The opposite is true for those condos with concrete parking garages. Those concrete deck surfaces not only need to have good drainage but also in some areas may need a good waterproofing seal coating applied periodically to protect the steel reinforcement within the concrete slabs from road salts commonly used in New England.
The Façade?
Façade thermal expansion and fenestration (window) penetrations require the use of caulk and other joint sealing compounds. Any material depending on adhesive properties will fail with time allowing water infiltration. These materials need to be monitored and replaced as needed. Windows rarely fail. It is the perimeter caulking and flashing serving the role of moisture infiltration villain.
Below the façade is the foundation of course. Flooded basements and damp walls concealing mold and other problems are well known water issues. A great deal of condo money is spent on internal wall waterproofing materials and repairing foundation cracks with a variety of sealants. Is this how to fix a leaking boat? No, boat leaks should be fixed from outside the hull. The same logic works for buildings. Stop the water from ever reaching the foundation wall. Heavy rain does not cause the ground water table to rise. All water reaching the foundation wall comes from the ground surface in the form of rain, snow melt, or surface drainage toward the foundation. Sometimes sloping the ground surface near the foundation to shed water away from the building is all it takes. Sometimes sealing the perimeter ground surface is the answer before the more expensive underground foundation drain solution is attempted.
Just Say Water…
And let us not forget perhaps the condo’s most expensive asset, namely, the parking lot and driveway bituminous surfaces. Here again water is the first suspect for surface cracking and reoccurring potholes. Storm water penetrates the surface cracks and undermines the soils washing them out or causing them to expand through freeze/ thaw cycles creating upward pressure expanding the cracking even more. Seal coating is just a form of painting the surface for eye appeal and seals very little. Pavement problems need to be resolved by more invasive means with the help of an engineer or competent contractor. The good news is the source of your maintenance problems is not hard to find, just say water.
Article written by Jack Carr, P.E., R.S., LEED-AP, Criterium Engineers