ergy code.
54 Incorporating Thick Layers of Exterior Rigid Insulation on Walls Wall assemblies are one portion of the building that provide a separation between the inside environment and the outside environment. This separation is often referred to as a building enclosure or a building envelope. For wall assemblies, control of rainwater, airflow, water vapor flow, and heat flow are key factors to providing a durable enclosure. The control of these elements can be separated into four principle control layers. They are presented in order of importance: u A water control layer u An air control layer u A vapor control layer u A thermal control layer The best place for the control layers is to locate them on the outside of the structure in order to protect the structure.
55 Incorporating Thick Layers of Exterior Rigid Insulation on Walls u u u There are three principle control approaches to dealing with water in the vapor form. The first is to let the water vapor pass through the assembly from the inside out and from the outside in. This type of wall assembly is called a flow-through assembly and can dry to both sides. The second is to locate a distinctive vapor control layer to retard the flow of water vapor into the wall assembly from either the inside or from the outside. This type of assembly is called vapor control layer assembly. The most common location for a vapor control layer is on the inside warm in winter side of the thermal insulation. The third is to control the temperature of the surfaces where condensation is likely to occur by raising the surface temperature with insulation. The most common method of achieving this is to use rigid insulation on the exterior of assemblies. This type of assembly is called control of condensing surface temperature assembly. When rigid insulation is added to the exterior of the structural sheathing, the interior surface temperature of the structural sheathing is increased since the insulation keeps the sheathing warmer. By raising the temperature of the condensing surface of interest sufficiently, condensation from interior water vapor migrating into the wall assembly does not occur. This allows assemblies to be constructed in cold climates without interior vapor control layers. The building codes recognize this and provide guidance on the minimum thermal resistance values of rigid insulation required to control condensation, when Class I and II vapor retarders are replaced with Class III retarders in specific regions.
56 Table 5 is information taken from Table R Class III Vapor Retarders of the 2009 IRC and Table R Class III Vapor Retarders of the 2012 IRC and provides guidance for thermal resistance values to control condensation for Climate Zones 5, 6, 7, 8 and Marine 4. Table 5. Thermal resistance values to control condensation for climate zones 5, 6, 7, 8 and marine 4 from (2009 IRC and 2012 IRC).
Moisture Aside from structural concerns, the most important consideration for foundation design is moisture. No client wants a wet basement. No client wants a damp basement. No client wants mold in their
Basements are Changing John Straube, Ph.D., P.Eng Basements: New & Retrofit Energy Efficient, Durable, Healthy Increasingly used as living space Not a root /coal cellar anymore! High quality space expected
ENERGY STAR Qualified New Homes Thermal Enclosure Checklist & Water Management Checklist Eli Caudill ENERGY STAR Version 3 Tighter Standards Whole Home Approach Better, More Sustainable Construction Surpasses
Comment Form on Gut Rehabilitation Alternatives Name: Organization: Email: Instructions Submission: Please submit this form to email@example.com by October 10 th, 2012 with the subject line
Dow Chemical is a Registered Provider with The American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members.
More Bang for Your Buck: Combining Thermal, Air and Water Barrier Linda Jeng, Dow Building Solutions 2014 RESNET Atlanta, Jan. 29, 2014 Actual high: 30 F Actual low: 12 F Effect of polar 