Advancements in building technologies have produced both lighter-weight materials that help reduce initial construction costs and the ability to create tighter building envelopes, which can lower lifetime energy costs. As beneficial as these overall savings are, using such technologies poses the potential for moisture damage and associated costs down the road.
Fortunately, the right combination of building technologies, products and installation techniques can net the benefits of efficiency and economics while also protecting against moisture damage.
Your First Defense Against Moisture
Moisture or water vapor moves in and out of a building with air currents, by diffusion through the building’s materials and through heat transfer. A building’s first line of defense is its exterior wall.
Here, masonry is a good choice for moisture control – as long as it is installed in such a way as to both prevent the infiltration of water, and direct any water that does penetrate down the exterior cavity of the building.
Different masonry types will require different installation and moisture-management techniques, but in general the National Concrete Masonry Association (NCMA) recommends the use of: ashing and counter ashing, weeps, vents, sealants, water repellants, post-applied surface treatments, vapor retarders and crack control measures. The association also points to redundancy of components so the wall will remain water tight even if one of the systems fails.
Strategies to Improve Moisture Management
One way to reduce the number of steps and materials necessary to achieve moisture control is for designers and builders to consider using properly-detailed single-wythe walls. These eliminate the need for a cavity wall as backup. Most contain an integral water repellant (IWR), drainable cores and an interior face shell. Used with ashing and weeps and a post-applied water repellant, they can keep moisture out of the interior envelope.
Another way to install masonry while incorporating redundant moisture management strategies is to use complete masonry systems. These combine structures that more easily transport water vapor to minimize mold, mildew and potential structural damage and incorporate stainless steel ties that won’t rust or corrode and drainage channels that send water down and away from the building. These systems also may be easier to install because of the combination of many products in one.
Finishing the Job with Repellants and Ventilation
Water repellants, which are added to both manufactured stone veneers and mortar, are another high-performance solution for controlling moisture. A complete moisture management solution should include the final step of sealing after the building’s completion.
Also important is the use of a proper ventilation system and avoidance of materials that aid in the growth of bacteria and mold, such as organic and paper-based products and wall-to-wall carpeting.
By using systems that combine water-resistant materials and technology to direct moisture down and away from the building, architects can help safeguard their clients’ investments — and health — from the damaging effects of moisture. Learn more about moisture management in our free guide, Controlling Moisture in Masonry.