Attic Air Sealing & Weatherization Chicago

Insulation slows the rate of heat transfer in or out of the house. Typically framing cavities (space between studs) are insulated with fiberglass, chemical foam, cellulose or mineral wool insulation to trap air. Air is a very good insulator. Picture the air gap between beverage thermos materials; one layer is to hold the beverage, with an air gap between the outer layer does not have contact with the inner layer creating an incredible resistance to heat escape or heat intrusion.

Loose fill / batt insulation is designed to trap air between layers but it is not a pressure barrier. A good insulation material will trap air, and keep the air still (such as closed cell spray foam or rigid foam board.)

Attic Air Seal highlights and benefits to existing homes.

1. reduce drafts at the lower levels of the home by stopping heat escape in the winter to the attic
2. reduce heating and cooling bills by eliminating leaks and unintentional air escape from the conditioned space

3. stop the dust ( dead skin and hair ) from clogging the trim covering the gap between the drywall and floor
4. prevent a mold food source ( condensation / evaporation cycle)
5. prevent unintentional air exchanges in the conditioned space. On sidewalls of the home, there may be gaps between framing members.

Existing Insulation Evidence : find a perfect black line corresponding with the seam between the drywall and framing called the bypass. This seam is accompanying the gap between the trim / baseboard / drywall / floor of the living space below. This is a direct result of skin dust and hair which is pulled up through stack effect to the attic from temperature differences between the attic and the living space. The black lines of the photo are not mold (commonly confused and misdiagnosed) it is skin dust and hair from the living space. The fiberglass insulation does not stop air movement. No loose fill insulation stops air movement.

To verify this process of finding skin dust and hair in the attic, shake out your blanket in the morning with a bright light and notice the dust that fills the air. This dust is pulled between gaps in the room up and out to the attic. This is the same air that leaks and escapes from the heated bedroom resulting in unintentional air exchanges, a drafty lower level, higher bills, mold food in the form of condensation, premature snow melt, icicles, ice dams and more.

Lights fixtures, electrical outlets, plumbing, ductwork vents, chimneys all create (swiss-cheese) holes in your bedroom ceiling…These are unintentional breaks in your pressure (air) barrier.

Any unintentional gap /hole in your ceiling creates air movement, air exchanges, is unintentional thermal transfer. Meaning your home is loosing heat in winter, and gaining heat in summer.

• Seal the Gaps. Mind the Gaps.
• Sealing the exterior building envelope properly which requires re-caulking every few years in the
• Chicago area due to extreme heat and extreme cold
• Air seal the entire attic floor at all seams and penetrations
• You will see an immediate considerable improvement in comfort and efficiency.

A complete pressure barrier (winter cap) of the homes top floor is essential to preventing heat escape. The can lights puncture the drywall and create (open windows) for heat to push its way through and reach the attic vents and go straight to the exterior. The can lights box trim have little holes where heat passes through. This causes you to literally heat the outside in winter with your paid gas from your furnace.

1. This wasted heat (wasted energy) raises the cost of heating, but that is often the smallest concern.
2. Bigger concerns are the moisture and humidity created in the attic leading .
3. Creates a drafty home by allowing heat escape at the top of the home and air intake at the bottom of the home. Stack effect will create a cold downstairs with cold air intake around seams regardless of wind or not.

Air Sealing Can Lights can be performed with a few different sealants, drywall, rockwool, mineral wool covers and or course retrofitting existing bulbs with Recessed Lighting Trims that stop air leaks.

DIY Can light covers are challenging in two ways, one is maintaining a true tight seal around the light so it no longer leaks, and the other is accessibility of the can lights.

Green Attic uses drywall to created air tight fireproof boxes around existing can lights to stop air leaks from the conditioned living space. Air sealing attic is the first step in fixing problems around the home created by stack effect from leaking pressure barrier of the conditioned space.

Older can lights require a minimum distance around the light housing to prevent a fire. Lights should be replaced with cooler burning bulbs (older bulbs run around 200-250 degrees Fahrenheit, while new bulbs run much cooler around 100-125 degress Fahrenheit).

Can light covers are placed over each can light using drywall and one part spray foam around the seams to create a perfect air seal and prevent heat escape in winter to the attic and outside.Each can light must be properly sealed to prevent heat escape ( heat rising from the conditioned space).

The combination of sealed plumbing, hvac, chimney, bypass, and electrical penetrations with sealed can lights creates a properly sealed attic floor. Now we can focus on fresh air balanced intake and exhaust ( ventilation.)

Can light covers are placed over each existing can light on the top floor of the home which is in direct contact with the attic using drywall and one part spray foam around the seams to create a perfect air seal and prevent heat escape in winter to the attic and outside.

Air sealing is one of the most critical features of an energy-efficient home. To add insulation without air sealing attic first is dereliction of duty. To prevent air leakage, it is best to seal the building envelope during construction prior to the installation of the drywall. A “blower door” test is a good way to identify air leakage paths so that they can be sealed using an appropriate material.

Preventable problems include
• condensation
• drafty rooms
• mold growth as result of condensation
• constantly cycling furnace and air conditioner
• higher than usual energy bills
• dusty rooms
• reduced air quality

Air Sealing leaks around penetrations in the home is the first and most cost effective step to reducing drafty homes.
Draftiness can be measured in air exchanges in the conditioned space.
Keeping the house snug and tight is commonly referred to as weatherproofing your home. This includes blocking drafts around windows, doors, and plugging cracks and gaps created by pipes, hoses, and exhausts.
Once the home is protected from drafty wind pressure from the exterior, you can begin to focus on air quality and air exchange improvements from the interior.

Shielding the home from wind pressure is essential to reducing “cold walls” in winter, air exchanges of heated ( paid for conditioned air.) Even if insulation is between studs, draftiness can still occur from wind pressure forcing cold outside air into the walls of through exterior seams.

Once the air is in the walls, it move by path of least resistance to the first available opening such as an outlet or seam where the floor and walls meet.

We often find mold growing on the sheathing of well insulated attics, because loose fill fiberglass does not stop air movement or heat escape from the living space.Without air sealing the attic floor, the heat will still rise and meet cold winter air from passive ventilation leaving food for mold growth in the form of warm air turning to condensation. The solution is air seal attic floor, baffles and vapor barrier around attic parameter, proper ventilation, and adequate insulation.

Meticulous air sealing is a hard work due to attic temperatures, existing itchy fiberglass, nails on the sheathing and a significant drop to floors below.

Air Sealing the attic floor with one part spray foam is the first step to a comfortable energy efficient home where draftiness is eliminated by stopping heat escape from the heated living in winter.

1. Wind Effect
2. Stack Effect
3. Combustion and Ventilation

Three types of air exchanges occur within your homes ( conditioned ) space. The first two are the secret to a comfortable home. The this is the secret to a healthy home.