Attic Insulation for Existing Homes

When tackling an attic insulation project, we always recommend removal of the old insulation. Working with a clean slate allows the best possible job and we get rid of any contaminants left behind by time and four legged lodgers.

There are two distinct ways of insulating an attic: keep the insulation on the floor (unconditioned space) or insulate under the roof (conditioned space).

Unconditioned Attic Insulation

For an unconditioned attic we use spray foam to seal up all openings, big and small, between the living area and the attic space. Without air sealing, conditioned air will continue to heat the attic leading to winter ice dams and possible mold issues. Air sealing cannot be ignored. If your home has soffit vents, we will install the necessary ventilation baffles to bring outside air into the unconditioned attic. Finally, a thick blanket of blown cellulose insulation is installed to an R-value of 60.

This approach to unconditioned attic insulation is very effective and isolates the living area from the attic. Properly executed unconditioned attic spaces work extremely well and we recommended them if the attic is not used for anything. In a two story house, the air sealing and high R-value that we install will make it much easier to achieve comfortable temperatures on both floors. The hot upstairs rooms that are common in the summer will be a thing of the past.

Conditioned Attic Insulation

Conditioned attics are a given in homes with finished living areas under the roof but we also recommend this approach if there is a furnace or air conditioner in the attic. In a conditioned attic, polyurethane spray foam is applied all the way from the eaves to the peak of the roof. Foam insulation is amazingly effective at keeping the attic cool in the summer. A traditional unconditioned attic can easily reach 140 degrees on a sunny day; with foam insulation in the roof it will be within a few degrees of the rest of the house. While it is sometimes possible to install ventilation baffles between the foam and the roof, it is not required and more often than not, the foam is sprayed directly against the roof sheathing. Please note that only spray applied foam can be used in an unvented system and that the foam must have low vapor permeability in our climate. Open cell foam should not be used.

Conditioned attics hold the furnace warmth inside in the winter and the heat out when the sun beats down on the roof in the summer. Your furnace and air conditioner can supply air at the right comfortable temperature through the duct work without struggling and the efficiency of the system is much improved.

Hunting the gaps
Attic floors are full of holes that must be sealed to prevent air movement from the house to the attic.
Walk-up stairway
This customer chose to abandon her storage attic so the stairs were no longer needed. The opening was sealed with plywood leaving a new insulated hatch for access should it ever be needed
Air sealing with foam
In this home, a bathroom soffit was open to the attic. It was blocked off and sealed with foam.
Cellulose is reprocessed paper and an excellent choice for insulating an attic floor when there are no restrictions on how thick the insulation can be installed. We recommend 18" installed depth which equals R-60.
Cellulose insulation installed
When completed, an attic with cellulose will look like this, a uniform blanket of insulation, which covers everything. The skylight shaft in the background was foamed to prevent heat loss.
Cellulose or foam?
Cellulose is a cost effective insulation material for attics but some customers prefer the cleanliness that only foam can provide. Foam also has higher per-inch R-value and it is the better choice where the depth of the insulation must be limited.
Conditioned attic space
This customer chose the conditioned attic approach because of the ductwork and a furnace in the attic.

January 31, 2009

Torsten R. Hansen
Pure Seal, Inc.


Dear Mr. Hansen,

We are so pleased with our decision to hire your company to insulate our two-story, four bedroom house in October 2008. We just had to take a moment to thank you again for helping our family stay warm and comfortable in our house.

Our investment in attic insulation has already paid off for our family! Our average actual monthly gas usage was over 20 MCFs per month during the winter months for the past three years. I am pleased to confirm our monthly gas usage is less than 15 MCFs per month (and it has been a cold November, December and January). Our gas bills compared to our friends / neighbors must be substantially lower.
Prior to our installation of the Pure Seal insulation, our thermostat was set at 75 degrees or more, and it was never quite as comfortable as we needed it to be… and with two young children we needed the house to be more comfortable in every room. Our thermostat has not moved above 64 degrees, and our house has been very comfortable.
During the brief periods of thaw, I cannot believe our house is the only house in our development with a thick blanket of snow on the roof and no icicles hanging off the gutters. Every year, the icicles were huge… and it must mean our heat is staying inside instead of escaping into the outside air through the roof.

Airsealing and insulating the thermal bypasses between the living area and the garage and the attic space with environmentally safe materials was important. Installing insulation barriers and access panels was also worth the money. We are glad we chose Pure Seal, and knowing you stood behind your product and installation and your installers were polite and thorough… gave us peace of mind. Your quote was more competitive than other firms… and we would tell anyone it would be worth hiring your firm and installers (even if it was more!).

The return on our investment will be shorter than we thought. It is difficult to save for capital improvements, but we are glad we made the investment! We also plan to itemize the expense on our taxes.

Should you decide to promote your services to our neighbors in Mentor or in surrounding areas, you have our permission to share this letter.

Kindest regards,

Kathryn and Patrick Cassidy

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