All masonry chimneys, metal flues, and heat sources must be sealed using fireproof caulking and metal flashing. Combustible materials must maintain proper clearance. This includes kitchen fan ducts. Note that the bottom of the joist next to the chimney is sealed with foam at a proper clearance.

The plumbing wall or wet wall leaks large amounts of warm, moist air, and should always be sealed.

All plumbing, stack pipe and electrical penetrations must be sealed.

Bath fans, AC boots, and any other mechanical penetrations must also be sealed.

All access doors and hatches, including knee wall accesses, must be weather-stripped with q-Ion, securely stapled, and backed with a bead of clear caulk.

Whole house fans are large sources of air leakage, and you may be asked to build an insulated, airtight box over the fan. The following instructions are what CSG has found to be most effective and practical.

Measure the fan in the attic and cut rigid fire rated foam insulation board for the sides of the box. Make sure your sides are tall enough to fit above the fan.

Pull-down stairs should be treated with airtight fire-rated insulated boxes. Boxes must sit flush over the opening to maintain an airtight seal. They must also include a gasket on the bottom perimeter, a strap or latch closure so the box can be tightened down and be a minimum of R-13. All gaps and cracks in the framing must also be sealed.  Seal all edges of the pull-down with foam or caulk, and all edges of the added carpentry with latex or silicone caulk.

Let the foam and caulking dry before setting the attic stair cover down.

Dropped soffits, usually found in bathrooms or kitchens, are often open in the attic, and may contain recessed lights.

Openings should be sealed with approved materials, and applied securely enough to support the weight of any added insulation. Strapping may be required for any gaps wider than 24" apart. Note: recessed lights can be covered in this case. Proper clearance must be maintained over and around all heat sources within the dropped soffit area.

Be aware of air sealing opportunities in knee walls. Bath fans, wet walls, top plates, chimney chases and other penetrations should be sealed if accessible.

If the knee wall transition is exposed and accessible, it should be sealed with rigid foam board, reflectix or another approved air-sealing material. Cardboard is not approved.

As with attic hatches, all knee wall hatches must be weather stripped as part of air sealing or hatch treatment unless the knee wall is inside the thermal envelope.

Unless otherwise noted on the air sealing work order, highest priority should be given to the sill plate and rim joist area, where air leaks in from outside.

All other accessible exterior penetrations should be sealed, such as oil intake pipes and electrical penetrations.

If the thermal and pressure boundary are determined to be at the basement ceiling, major leakage areas including plumbing penetrations, tub cut-outs, heating registers, open wall plates and electrical penetrations should be sealed.

Damming must be provided around all heat sources, storage platforms, accesses etc. Damming must be at least as high as the surrounding insulation and must permanently maintain proper clearance from heat sources.

The following must be dammed:

Storage areas

Floored walkways 

Bath fans 

Drip pans

Access hatches

Chimneys/flues

Recessed lights

Whole house fans

Air handlers

Other mechanical equipment

When using fiberglass for damming, batts must be laid flat -not on edge where it might fall and placed without gaps that may let cellulose through.

Damming heat sources: 3" clearance is required around all heat sources including recessed lights, bath fans and chimneys and double-walled metal flues. 6" is required for single walled flues, and kitchen exhaust ducts. Insulation cannot be blown over any types of recessed light.

Pre-existing insulation inside the clearance area should also be removed when damming the fixture.

Air Handlers and other mechanical equipment must be carefully dammed to prevent any cellulose from coming into contact with the unit. Be sure to clean out AC condensate drip pans.

Damming material can be fiberglass batts, metal flashing, carpentry or rigid insulation. Rigid damming must be securely fastened to framing members to prevent it from falling over. Attic access hatches must be dammed with fiberglass. No rigid material is allowed for safety reasons.

Pipes in attic spaces will be tented when possible to prevent the pipes from being cut off from the heated area and freezing.

Clean out any insulation under the pipes. Build up fiberglass beside the pipe and lay a batt down over the pipe. Insulation can then be blown over the tent. Call CSG whenever pipes are discovered that are not addressed in a Pipe Disclaimer.

3.5" fiberglass batts are normally recommended for kneewalls. This area is also often treated with rigid insulation board with a thermal barrier (below) when possible.

All seams with framing and between boards including tops and bottoms of the foam boards must be sealed.

The knee wall slope and gable end wall can be insulated with fiberglass before rigid insulation board is added, or dense cellulose can be blown in. Fiberglass insulation left exposed must be un-faced.

2" rigid insulation board with a thermal barrier rated for use in knee wall spaces is used to cover the fiberglass or enclose the cavity for cellulose. It should be attached with 2 W' screws and fender washers. All seams should be foamed or taped with metal tape.

The rigid insulation board can be drilled through after installation and cellulose densepacked behind it when recommended.

When the knee wall slope is called to be brought inside the thermal envelope, the insulation board should be brought all the way down if possible to block the soffit area (left), and all the way up to block the attic slope area (right).

Unvented attic slopes will be dense packed either from the attic or knee wall, or by interior drill and blow if the slope is too long to be effectively insulated from those areas.

The slope must have at least four inches of space between the roof sheathing and any existing insulation in order to be dense packed. A fiberglass batt will be used to block the opening at the knee wall to prevent cellulose from spilling out.

Soffit vents openings must be cut to the full, correct size before the aluminum vent is put on. Louvers should face into the house (above).

Vent chutes must be installed for all open soffits for the full width of the rafter bay (24" on center will need two vent chutes per bay.) Fiberglass blockers (wind baffles) will be installed at the bottom of each vent chute to prevent wind wash and insulation from blocking the soffit vents.

Insulation should be blown to the same level all the way out to the exterior wall top plate. Tapering is not allowed.

Bath fan vented to roof flapper.

Insulated hose must be used at all times and secured to the roof jack with a zip tie.

Note: a loop or trap is recommended to be left at the bottom of the insulated hose to help prevent any water from running back into the fan. If venting a bath fan through the roof is not practical, CSG may ask you to vent it to a gable wall flapper or to the soffit. Note: If a bath fan can't be vented, you cannot insulate. Contact the contractor hotline whenever this is encountered.

Wood shingles are scored at the top and snapped off with a pry bar.

Clapboard and shingle are scored at a 45-degree angle at the top and removed in one piece whenever possible.

Vinyl and aluminum siding should be carefully unzipped, the nails at the top of a course removed, and the entire piece taken off. Bending the course upwards risks unnecessary breakage. If any face nailing will be required to secure these types of siding, the customer must be notified beforehand.

Holes will be drilled between all studs, cross-braces and firestops.

Lead safe rules must be followed. Painted siding must be removed, or HEPA vacuum attachments must be used to drill through painted surfaces.

The preferred method of dense packing is to use a fill tube.

Holes must be plugged with foam or wooden plugs, and any other weather barriers (Tyvek) repaired.

Siding must be replaced with a minimum of damage. Shingles and clapboard are tapped back into place and secured with appropriate nails.

Nail holes and cracks or splits should be caulked. If splitting or cracking cannot be repaired, replacement siding should be installed.

Some splitting, cracking and paint chipping WILL occur, but attempts must be made to repair damaged siding. Be sure that the customer understands what is reasonable to expect from the repaired siding.

Fire rated rigid foam insulation board can be used on crawl space ceilings. All seams should be sealed with foam or metal tape.

Insulation should be in contact with the cold surface and inserted neatly in place. FG batting must be un-faced. The rim joist must be air sealed prior to installation of the insulation.

Garage ceilings will be dense packed by drilling holes in the ceiling. Holes should be plugged with styrofoam or wood plugs and sit flush with the ceiling. One coat of joint compound is also required.

All wood surfaces that are drilled into must be plugged with a wooden plug inserted flush with the surface and treated with one coat of wood compound.

Asbestos-like material should never be disturbed. Work should not continue in the immediate areas, and a blower door test should not be done.

Vermiculite may contain asbestos and should not be disturbed. Blower doors, air-sealing and blown insulation cannot be done.

Thermal work in the area of the home with knob and tube wiring cannot be done until a licensed electrician has certified that it is not active. If you encounter any knob and tube wiring that you believe has not been cleared by CSG, contact the contractor hotline. Air sealing may be completed upon discretion of the contractor.