COLUMN BUILDING SCIENCES FIGURE 10 The best way to remove moisture from the attic space is to provide air FIGURE 11 Spray foam insulation can be directly applied to the interior of concrete change. Air is exhausted from the peak of the attic using an exhaust fan ducted to the exterior. foundation walls. Exhaust Fan Ducted From Peak HD Spray Foam Sealant Hybrid Fan Controller Motorized Damper HVAC Supply Water Control Layer Capillary Break Return HD Spray Foam Balanced Ventilation Strategy for Conditioned Space Attics Exhaust and Return Ventilation Sized per 2019 IRC Steel Stud Assembly Concrete Foundation Wall Gypsum Board Wherever unvented conditioned attics are constructed, a means of moisture removal from the attic is necessary. The "conditioned" part of unvented conditioned attics is important. One of the best ways to remove moisture Damp Proofing Filter Fabric Coarse Gravel (No Fines) Perforated Drain Pipe Capillary Break Over Footing (Damp Proofing or Membrane) Concrete Footing Desiccant and Energy Recovery wheels available in standard and custom sizes. Call or email us for a quote today! 225 -753 -1700 1700 64 ASHRAE JOURNAL ashrae.org FEBRUARY 2020 Polyethylene Vapor Barrier Granular Capillary Break and Drainage Pad (No Fines) from the attic space is to provide air change.† In this approach air is exhausted from the peak of the attic using an exhaust fan ducted to the exterior. This creates a slight negative air pressure in the attic, and air is drawn from the house below. To create "balanced' ventilation in the house, supply air is provided from the outside to the return side of the air handler (Figure 10). The amount of air supplied and exhausted should be the same-hence the term balanced ventilation. The quantity of this airflow should be based on the International Residential Code - 2018. To prevent over ventilation or under ventilation, a motorized damper is installed at the outdoor air supply of the system. The operation of the motorized damper is coupled or linked to the operation of the attic exhaust fan. The attic exhaust fan operates only when the motorized †It info@rotorsource.com | www.rotorsource.com Bond Break Sill Seal Thermal Break and Capillary Break Concrete Slab is not the only way; coupling the attic to the occupied space of the house is another. Dehumidification is yet another. Balanced ventilation with heat recovery or energy recovery is also an option, and as in Figure 10 when I use heat recovery or energy recovery, I prefer to exhaust air from the peak of the attic and supply air to the occupied portion of the house.http://www.rotorsource.com https://www.ashrae.org/