– SPRAY FOAM FLASH AND BATT – our methods for tighter insulation

 

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The basic Flash and Batt method 1″ of closed cell spray foam with fiberglass batts installed on top

Closed cell spray foam is probably the best way to insulate a house since it not only seals all air gaps but the closed cell also stops moisture migration, reducing conductive heat loss. However, spray foam is also the most expensive insulation. G_space uses a flash and batt technique to gain the efficiency of spray foam without the cost. Applying a 3/4″ -1″ coat of closed cell spray foam to the outside of the insulation cavity with Fiberglass batt insulation filling the rest of the insulation cavity, allows the batt insulation to be much more effective since the air infiltration gaps that always occur with Batt insulation (greatly reducing its average R value) are stopped.

G_space is committed to building the highest level of energy efficiency in building envelopes that our clients’ budgets allow. While alternative energy sources like solar, wind, geothermal, ect, are wonderful, a building should first retain the heat generated with a high performance envelope. (Stop the patient’s bleeding before giving a blood transfusion 🙂  ) We utilize rain screens, insulated sheathing assemblies, spray foam sealing, green roofs, insulated protected roofing membrane assemblies, Passive house techniques, and other methods to achieve the highest practical R value. Achieving these R values may relieve the need for such expensive alternative energy sources.  Here are some of out methods

foam-IMG_1607For even greater cost savings we used left over scrapes of 1″ rigid board insulation loosely applied to the back of wall sheathing, then spray foamed the edges and joints. This allows the expensive tanks of spray foam to stretch further in covering exterior walls.

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Here a metal stud walls built with 4″ studs on 12″ oc staggered inside and outside to a 6″ thickness. The outer stud is encased in spray foam to reduce the heat conduction issue associated with metal studs. The inner cavity will be filled with fiberglass batt

 

When foam is used in a roof / ceiling assembly, the ventilation space above the batt insulation is not needed, since migrating moisture vapor never reaches the cold outside surface and is stopped by the vapor barrier effect of the closed cell.

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Here the old double width brick walls, so common in Philadelphia where G_space does many building renovations, when furred out with studs, the fiberglass batt insulation is very ineffective since air infiltrates the old brick and moisture migrates thru the brick conducting heat. Spray foaming the brick first with closed cell foam dramatically increases the overall R value of this type assembly.

 

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Finally, a simple retro fit insulation technique is to add a continuous layer of rigid foam board over existing drywall, then install a new drywall over the insulation with longer screws. We like to use a minimum of 2″ thickness for the foil faced rigid board. This creates an air barrier and increases R value without the mess of demolition of the existing wall finishes. Also 1/2″ or 3/4″ insulation board is added to the sides of window openings to reduce heat loss in the vulnerable areas.

G_space is committed to building the highest level of energy efficiency in building envelopes that our clients’ budgets allow. While alternative energy sources like solar, wind, geothermal, ect, are wonderful, a building should first retain the heat generated with a high performance envelope. (Stop the patient’s bleeding before giving a blood transfusion 🙂 We utilize rain screens, insulated sheathing assemblies, spray foam sealing, green roofs, insulated protected roofing membrane assemblies, Passive house techniques, and other methods to achieve the highest practical R value. Achieving these R values may relieve the need for such expensive alternative energy sources.

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