New Course: Danger in the Damp–Dealing with Mold

Architects Training Institute’s new course is called Danger in the Damp—Dealing with Mold. It will examine the design and construction methods of systems designed to withstand water penetration. It will start with an understanding of these systems and finding the source of intrusion then repairing and prevention.

This course teaches the following specific knowledge and skills:

  • Terminology used to discuss how entrapped water creates problems for building users
  • Measures to retard the infiltration of moisture into built environments
  • Where and why mold growth occurs
  • Testing and inspection to find water damage
  • Systems and procedures to inventory moisture damage following intrusion
  • Immediate and secondary actions steps to take following water intrusion
  • Indoor air quality issues and how to identify them
  • How to deal with mold growth, once it is discovered

Here is a course excerpt on the ways to reduce the chance of water intrusion:

 

There are straightforward steps that can be taken to reduce the chance of water intrusion. Specifying and using building materials that neither accept nor hold moisture is one practical solution. For example, rigid insulation will not hold moisture, whereas cellulose insulation will absorb the same. Metal siding will repel water, but wood siding becomes saturated unless protected. Single ply membrane roofing offers no lapped joints wherein moisture can reside, but that is not true of asphalt shingle roofing. Sandwich panels containing insulation faced with steel or aluminum sheeting are another prime example of materials which by their nature, repel moisture.

Construction detailing using forethought before construction begins can deny water entry. It is primarily based on a good imagination and an understanding of water behavior. Since precipitation tends to flow downhill, flashings below copings, below windows, above door and window openings and above breaks in the continuity of the building envelope where water should lap down over the next shield in the water barrier, will keep water from entering. If wind striking a building face has the potential to drive water up under flashing, then caulking should be specified, or other barriers put in place to prevent that. Capillary breaks can prevent water from bridging gaps. If there is a cavity into which moisture can enter and collect, weep holes should be provided to let that collected water drain from that cavity, back to the exterior. The devil is in the details, but unwanted moisture intrusion can be in the lack of them.

The above-mentioned material specification and detailing decisions should be choices made during the design process. The idea is to create a continuous envelope of materials that repel water and will not allow moisture to get through them and into the interior.

Another useful tool is ongoing efforts to find and eliminate any newly created gaps in the envelope through which moisture can get inside. Inspection during construction is the best time to do this, but it is also part of ongoing maintenance efforts. Indoor sources of moisture (other than the breath of inhabitants) can be found and fixed or eliminated. Uncontrolled air movement that pulls humid air in from the exterior can be controlled with airlocks or other known design devices.

New Course: Drier By Design – Designing to Keep Water Out

Architects Training Institute has a new course called “Drier By Design-Designing to Keep Water Out.” This course will focus on moisture resistance principles and methods in a systematic fashion. This course teaches the following specific knowledge and skills:

  • A basic understanding of how water moves, migrates and behaves
  • Typical sources of excess moisture in our build environments
  • Proactive prevention of unwanted moisture through planning and design
  • Methods used during construction to prevent the intrusion of water
  • Post-construction prevention of leakage by building envelope inspection
  • Common points of failure through which water can gain entrance
  • Prevention of water intrusion through control of condensation

Here is an excerpt of the course giving you several general rules of thumbs used to determine where to specifically locate vapor-resistant materials in roofs and walls.

 

Basements and crawl spaces are always susceptible to water accumulation, but precautions can be put in place to minimize the risk. The grade should be sloped away from the structure to prevent groundwater from standing against it. Downspouts should be extended above or below grade to discharge points well away from a building, with connections checked on a regular basis. Gutters and downspouts should be kept clean. Below-grade walls should be sealed to resist moisture intrusion. Drains and sump pumps can be installed below floor levels to capture and expel any moisture that does make it inside the space. If installed and depended upon, proper operation of these pumps should be tested on a regular basis.

Walls will be either face sealed or drained cavity assemblies. Those which are drained, like masonry veneered walls, should have a secondary barrier installed behind the first face. At the bottom of this secondary cavity should be materials and methods to collect unwanted water and redirect it from the interior, back out to the exterior. Those which are sealed on their faces only, like EIFS finishes, have only one barrier with which to resist water penetration. Unless very close attention is paid to detailing during installation, these type finishes are very likely to fail.

Humid air moving into and through roof and wall cavities is a major transport mechanism of moisture. In cold climates, warm, moist inside air should be kept from exfiltrating out of the envelope. In hotter climates, warm, moist air must be kept from infiltrating inside. Pressurization and depressurization of the interior in response to exterior pressure changes can help slow down that air movement, even in high-rise construction that creates a stack effect.