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Real World, Real Success: Retrofit Insulation Application in Milwaukee
A recent retrofit job near Milwaukee, WI netted a 23% improvement—on a home that was already deemed mostly airtight—in a before/after blower door test conducted by the Wisconsin Energy Conservation Corporation (WECC). All installation was performed by Wisconsin Insulation Service (WIS) with technical assistance from Owens Corning.
- Date: September 8–9, 2009
- House type: Ranch, single
- House size: 1,200 sq. ft.
- Date built: 1977
- Location: Hartland, WI (Milwaukee)
- The homeowner had, in the past, added a bead of caulk and polyurethane foam at sill-foundation interface, and also fitted OC FSK batts into box sills. In addition, the homeowner had recently re-sided the house and caulked all OSB sheathing joints. This was the condition of the house at the time of initial blower door test.
- The attic was constructed of 2x6 trusses with rock wool blown in. The homeowner had loose-laid 1" bead board over the rock wool.
Description of Work:
- Conducted blower door test on house before any work (WECC).
- Removed box sill insulation and all attic insulation.
- Sealed attic.
- Sealed box sills (see photo for details)
- Re-insulated attic to R-50.
- Conducted final blower door test
Blower Door Testing:
This was performed by WECC.
WECC, who conducted the blower door tests, was expecting higher initial value (~1800). It was conjectured that the homeowner’s pre-caulking of sill plate and OSB sheathing joints during re-siding may have brought initial number down.
The focus in the attic was at the top plates and soffits, because they are frequently the largest areas of air
infiltration in existing homes: The attic EnergyComplete™ System retrofit took 2 hours and 20 minutes and consumed 1.5 pails of “part A.” The 100-ft. EnergyComplete™ System hose easily reached all areas in the attic with the machine set up in the garage.
1. Top Plate, Gable Walls: Cracks on either side of the top plates in the gable walls were easily visible. The top plates were sprayed on either side without any problems.
2. Top Plate, Interior Walls: EnergyComplete™ Spray Foam was applied to both sides of the top plate.
3. Top Plate at Roof Soffit: Due to the capability of the gun to shoot 4–6 feet, this was not as difficult to get to as initially thought. The following process was used to effectively seal these areas:
- Attic rafter vents were first installed down to the soffit vent (Owens Corning raft-R-mate® vents are recommended)
- A piece of fiberglass batt was then pushed up against the rafter vent just past the top plate
- EnergyComplete™ Spray Foam was then sprayed over the top plate
4. Interior Soffit: An example of this is where the kitchen cupboards were located. The soffit above these cupboards was open to the attic (note that in new construction, such soffits are less common). The approach here was to staple cardboard over the soffit opening and spray the joints between the cardboard, ceiling drywall and beams. The recommendation is to use Owens Corning FOAMULAR® insulation or Fiberglas™ 700 Series board instead of cardboard.
This construction involved a layer of wood fiber board between the sill plate and the foundation block to help reduce
air infiltration. The homeowner had previously caulked and applied polyurethane foam on these interfaces. Despite
this, drafts could be detected (while the blower door was pulling negative pressure) where these beads had cracked or
were discontinuous. The decision was made to install EnergyComplete™ Spray Foam.
Basement installation comprised the following areas:
1. Box sills: Sealed on all horizontal joints.
2. Running plate: This interface could not be reached due to interference of the parallel joist (which obstructed
the gun). As a result, only the top of the joist could be sealed.
3. Piping/other: Sealed protrusions in the framing around pipes, wiring, vents, etc.
The EnergyComplete™ System allowed Wisconsin Insulation Services (WIS, an experienced polyurethane foam installer) to:
- Work without a full suit and air respirator, or displace the homeowner
- Provide complete coverage where air infiltration—a major cause of energy loss—occurs
- Provide maximum protection with revolutionary EnergyComplete™ Spray Foam, which penetrates deep into cracks and gaps
- Maintain the integrity of the seal throughout the life of the house because EnergyComplete™ Spray Foam is designed to remain flexible and compliant over time