Cellulose Insulation Install Starts With Right Preparation

SUCCESSFUL ATTIC RETROFIT REQUIRES GOOD PREP

The Cellulose Insulation Manufacturers Association (CIMA) recommends using a professional insulation contractor trained in the proper techniques of cellulose installation to achieve the maximum performance from an attic retrofit. However, a home owner should know what to do before the job starts and what preparation is required regardless of who does the actual installation.

Seal The Deal First
The first step to improving attic insulation is to make sure all air leaks are sealed. Even a perfect install will not achieve the full energy-efficiency if air leaks into or out of the conditioned space. Use a high DOE Energy Star image of how air leaks from a housequality caulk or other sealing products to block holes and cracks in ceilings and gaps at attic intrusions and transitions. These openings can cause a home to lose 30% or more of conditioned air.

This work can be contracted or done by home owners without the need for highly technical know-how or tools. Working in an attic is hazardous though. More than a few do-it-yourselfers (and even a few professionals) have been seriously injured stumbling over joists or falling through ceilings. Use plywood sheets as temporary work platforms. It can be a lot of work in pretty tight spaces and a bit messy.  To find openings, do a thorough inspection of the attic paying close attention to spaces around chimneys, vents and other protrusions through the ceilings. Also, turn on lights in the rooms throughout the house. Then find a safe place to be in the dark attic and look for light. Those are the places where air is also traveling in and out of the house.

Stopping air infiltration and exfiltration is a good thing, but there are other considerations no matter what type of insulation is used. A certain amount of fresh air is essential for a healthy living environment. Indoor air quality experts usually cite 0.35 natural air changes per hour as the minimum necessary. And there is the matter of combustion air for furnaces, gas stoves and fireplaces, etc. The highest efficiency gas or oil-fired heating devices have ducts that draw combustion air from outside, but most take the air they need right from inside the house.  That creates negative pressure, which sucks outside air into the home.  If the home is tightened to the point where this make-up air doesn’t equal the air consumed the appliances may not work correctly and hazardous levels of combustion products may build up in the home. That’s why it’s important to provide for adequate, controlled ventilation.

Clean Up While You Can
Of course it will be necessary to remove everything stored in the attic. A bonus for most home owners doing attic insulation retrofits is finding lost treasures long forgotten above their ceilings. But it’s also important to take stock of electrical wiring, recessed lighting, roof vents, duct work and other areas of your attic before several inches of cellulose insulation is blown in. Make repairs, or have them made, to shore up everything before starting the installation.

Preparing For Install
An attic must be ventilated to keep hot air from becoming trapped and creating wood rot and mold from forming. The eaves (the edges of your roof where the outside wall and the roof framing meet) must be prepared so the blown cellulose insulation will not block air flow. This can be done with attic ventilation baffles.

Barriers must also be placed around heat-producing devices, such as chimneys, furnace and stove flues and recessed lights.  Shields and covers designed for this purpose are available, or mineral fiber batts can be cut to maintain a three-inch clearance around such devices.

A rigid barrier should also be created around the attic access to keep insulation from falling into the house when the access is opened. The barrier should be at least an inch taller than the planned height of the installed insulation.  And, by the way, the insulation should cover the joists. If it doesn’t each joist is a thermal bridge through which heat moves out of and into the living space.

Plan ahead for how to handle the logistics of the installation. If the attic access is in the garage this will simply mean tidying up so there is a clear path to run hoses and allow work to be conducted unobstructed. When the attic access is inside the house more planning is needed. See one home owner’s personal account for ideas on what to consider when doing a cellulose insulation attic retrofit.

Selecting An Insulation Contractor
It is important to find an insulation contractor who is knowledgeable and experienced with cellulose insulation. CIMA’s website has tips about hiring an insulation contractor. You can also check with a CIMA Producer Member in your region for recommendations on contractors specializing in cellulose insulation.

These are just some of the ways to prepare. Taking these, and other steps, to properly plan and prepare for an attic retrofit with cellulose insulation will make a big difference in the final results and satisfaction. Let us know if you have questions, share a personal story if you are a home owner who has completed a job, or let our readers know other tips if you are an installer specializing in cellulose insulation.

 

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  1. Nate Adams says:

    Thank you for touching on the high importance of air sealing! I see a lot of attics with mold problems because it was a ‘blow and go’ job. It cheapens the image of our profession. I actually took the time to write a DIY Attic Insulation eBook that is very detailed on how to do it yourself, so I share your passion for doing it right, even if I don’t get paid for it. For the record, I prefer cellulose to fiberglass, despite coming from the fiberglass industry.

    • Rod says:

      Nate,
      I happened to see your comment. Just had an exchange with someone in the trade who was defending the use of fiberglass. We happen to use “stabilized cellulose”. I’d be interested to hear what you have to say about why you prefer cellulose. It’s always great to have a “third-party” provide a professional opinion!

  2. Rod says:

    Well-thought-out and written article. Many homeowners trying to insulate their attics take shortcuts. Good to see the steps in prepping the job included.

    Will be re-posting for others to see this!

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