Condo Media - April 2011 - 46

MAINTENANCE

by Dennis Kulesza

Water Tight
Sealing the Building Envelope
acility management has become more complex and demanding in today’s changing world. Concerns — such as strategic planning, ergonomics, benchmarking, accessibility, post occupancy building evaluations, partnering and downsizing — continue to devour a facility manager’s time. It is little wonder that building leaks do not rate preferential treatment. Inevitably, though, keeping a building safe from water infiltration becomes an important part of every facility manager’s duties. Water infiltration causes major problems to a structure. Water damages a building first cosmetically, and then structurally. It is important to realize that by the time a stain shows up on the interior of your building, most likely irreversible damage has been caused to the exterior. Water-soaked roof insulation will never dry out. The effective “R-value” of the insulation is now destroyed. Trapped moisture in insulation also can decay a roof deck and will cause roofs to fail prematurely. Water entering walls will rust steel relieving angles and carrying beams, which support the structure. Moisture penetrating reinforced concrete structures carry

chloride ions, which will rust reinforcing bars causing them to expand in size resulting in spalling concrete. As one begins to understand the mechanics of water infiltration, one begins to understand the importance of keeping a building watertight.

precast concrete or stone coping drip through-wall flashing cavity and concrete block cores grouted solid metal counterflashing lap wall flashing with roof flashing roof membrane through-wall flashing

Roof and Wall System
The best way to prevent water from entering a structure is to implement a scheduled maintenance program that incorporates routine visual inspections. Obtain a checklist and use it when inspecting roofs and walls. Roofs should be routinely inspected in the spring and fall. Inspecting a roof in the fall will allow you to ready your roof for the winter. Fall is a good time to check drains and gutters to see that they are free of debris. Clearing debris from drains is a simple task during mild weather, but it becomes difficult, if not impossible, once temperatures drop below freezing. Inspecting a roof in the

Figure 2– Cavity Wall Cross Section

wood blocking

Figure 1–Typical Roof Cross Section
penthouse wall wall cap flashing wall membrane counterflashing pitch pocket roof membrane cooling tower support wall flashing weep hole base wall flashing lead flashing

exterior building wall

cant strip insulation board

vapor barrier

concrete roof slab

spring helps identify damage caused to the roof over the winter. Make repairs before spring rains begin to prevent water from causing permanent damage to your roof. Cursory inspections also should be done after windstorms, and after any work is done to your roof or rooftop equipment. Walls are typically more durable than roofs and usually require inspection once a year. Many of the items on a roof checklist will also appear on the wall checklist — examples inlcude coping and counter flashings. This occurs because both the roof system and wall system depend on these building components to keep water out. These components make the transition between systems, and are actually shared by the roof and the walls. To help illustrate and explain the relationship between roof, wall and horizontal waterproofing systems within the same structure, it is important to have an understanding of the concept of the “building envelope.”

CONDO MEDIA • APRIL 2011

Condo Media - April 2011

Table of Contents for the Digital Edition of Condo Media - April 2011