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Chapter 9

AIR SEALING
INSTALLING INSULATION IN WALL CAVITIES

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Tools needed by volunteer:                                Materials needed:

Nail apron                                                             16” - R-19 insulation
Tape measure                                                        3” tape
Utility knife                                                           Caulk
4 mil plastic
Staples
Spray foam
1” foamboard insulation

Tools and equipment needed:

Generator
Extension cords                                                    
Lighting
Hammer tacker stapler
Caulk gun
Gloves
Dust masks
Protective glasses
Framing square

BUILDING SCIENCE FACTS

  • All of our homes are Energy Star qualified homes.  Our homes, on average, are 57% above Energy Star standard for 2009.  We achieve this from your great attention to detail.  We address energy conservation at every step of the building process, from framing to installing appliances.  Doing this gives us great end product that ultimately benefits the families that will live in the homes.  Keep up the great work!
  • We need to be intentional about sealing every penetration and hole in the house, both interior and exterior.
  • We want to stop air flow from exterior to interior, interior to exterior and from one level of the house to the other.
  • 40% of heat loss is a result of warm air (air leakage) escaping out of the house.
  • The better job we do at air sealing, the greater the R-value we can achieve from our batt insulation.
  • Fiberglass batt insulation performs the best when it enclosed and air sealed in a six-sided box.
  • Top plate
  • Bottom plate
  • Studs on either side
  • Foamboard or OSB on exterior
  • Drywall on interior
  •  Anytime we have airflow through batt insulation we can reduce the R-value by 50% or more.

AIR SEALING

  1. Caulk all holes in all of the wall and ceiling electrical boxes.
  2. Caulk or spray foam all holes in all exterior wall studs.
  3. Fill all holes in the top and bottom plates on interior and exterior walls.  Look for any unused holes and fill them.
  4. Caulk or spray foam all holes (being used or not) or gaps in the foam board or OSB that are visible from inside the house.
  5. Fill the gaps that are between window/door jambs and the framing.  For a hole that is ¼” or smaller use caulk; if it’s larger than a ¼” use spray foam. NOTE:  When using spray foam, only spray a small amount in the cavity at a time.  Have only one experienced person doing this.  Have that person go around and check all doors and windows for gaps in the spray foam.  Let the spray foam expand completely and then go back and fill the small gaps that need it.  A ½” depth of spray foam air seals just as well as spray foam expanding out past the window/door jambs.
  6. Caulk or spray foam all rimjoist penetrations such as dryer vent, plumbing pipe, etc.
  7. Install a ceiling baffle so ceiling insulation does not fall into areas over the porch.
  8. Cut pieces of 1” foam insulation to fill two layers at every window and door header and caulk.

INSTALLING INSULATION IN WALL CAVITIES

  1. Batt type insulation, like most things, performs the best when installed properly.  Failure to seal all air leaks and allow airflow across the insulation can cause the insulation to lose up to half of its insulation value.
  2.  Failure to fluff the insulation in the wall cavity, or compressing it as little as an inch can cause the insulation value to go from an R-19 to an R-10.
  3. Insulate all outside walls with (R-19) batt insulation.  Install loosely, never pack it in.  Slit the batt to fit over wires and pipes to avoid any air pockets.
  4. Cut out around electrical boxes.  Cut out the same dimensions of the box.EXAMPLE:  If the box measures 4” for the height, 3” for the width and 3” for the depth, cut out the insulation only to that size.  Be sure to install insulation behind the box.
  5. Do not insulate any ceiling areas.
  6. Take time to ensure insulation is fluffed/pulled out so it is flush to interior wall studs.  Make sure insulation fills space from top plate to bottom plate and from stud to stud.
  7. Install a 6 mil poly vapor barrier on the ceiling trusses taking care that the poly extends down the wall 12”.  Staple to the trusses, overlap seams a minimum of 2’ and tape.  Make certain the poly fits tight into ceiling corners so as not to disrupt installation of ceiling sheet rock.
  8. Install a 6 mil poly vapor barrier on all exterior walls.  Staple at every stud, plate and window/door rough opening.  Use care in wrapping in and around corners so poly does not bunch up and affect sheetrock installation.  Overlap seams a minimum of 2’ and tape.
  9. Tape all seams (PER CODE) to air seal the house. BUT, DO NOT TAPE THE SEAM AT CEILING CORNERS.
  10. After poly has been installed, cut it open by cutting an X at windows, doors, scuttle hole, etc.  Wrap around rough openings and staple.
  11. At each electrical or air opening, cut a small X inside the box and push the poly out and around the outside of the box for a snug fit.  ONLY TAPE IF FIT IS NOT TIGHT.
  12. If the plumber has run drain pipes for the tub, cover the hole in the floor for bathtub plumbing with OSB or foamboard and seal tight with caulk or spray foam.