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How Much Does Spray Foam Insulation Cost in the Attic of an Existing Home? (Prices/Rates/Factors)
Amanda Ringler

By: Amanda Ringler on December 16th, 2016

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How Much Does Spray Foam Insulation Cost in the Attic of an Existing Home? (Prices/Rates/Factors)

spray foam  |  attic  |  cost  |  foam insulation cost  |  insulation

Is snow melting on your roof before any of your neighbors’? Are ice dams forming on the edge of your roof? Do you find it hard to regulate the temperature of your home? If you answered yes to any of these questions, using spray foam insulation in your attic could help fix the problem.

These are just some of the key signs that you need to insulate or reinsulate the attic of your home. Other signs include high energy bills, upstairs rooms not maintaining the same temperature as the rest of the house, and issues with your roof.

After insulating thousands of attics in Michigan over the past 15 years, we know insulating your attic with spray foam can cure what ails you when it comes to saving money and keeping you comfortable. RetroFoam of Michigan uses spray foam insulation when insulating attics, crawl spaces and rim joists.

Attic insulation costSpray Foam Attic Insulation Cost

The size of the treated area in the attic to be sprayed is the largest contributor to the cost of the spray foam project. The bigger the space, the more expensive the job will be.

The total projected cost to insulate an attic in an existing home ranges between $5,000 to $10,000.

What Variables Determine the Cost to Insulate an Attic?

The type of material used is also a determining factor. On the majority of our projects, we usually use about six inches of open cell spray foam. In the case that an attic is sprayed with closed cell insulation, the cost of the project will be more expensive.

The thickness of foam sprayed is also a factor. The standard amount sprayed is six inches for open cell, but if more is needed then that will also effect the price.

How to tell if your Attic Needs Insulation

Here are some of the signs you may need new insulation in the attic:

  • Snow melting on your roof. If the snow on your roof is melting before the snow on your garage, then heat could be escaping from your roof and is melting the snow.
  • Ice dams form on the edges of your roof. Ice damming can mean poor insulation or poor ventilation. If the ventilation isn’t right, then there is a possibility that you have a traditional attic system with insulation on the floor of the attic and venting that runs up the roof deck. Even with proper ventilation, you can still get ice damming if there is heat escaping.
  • High energy bills. Your energy bills may be through the roof if you furnace or air conditioner are running constantly due to poor insulation.
  • The upstairs rooms don’t stay warm during the winter. A common complaint is that the rooms on the second floor don’t stay warm, despite the furnace continuing to run.
  • You replace your roof more often than normal. It isn’t normal to replace your roof every 10 to 12 years. The average lifespan of a roof is between 30 and 40 years. If you find yourself frequently replacing your roof, then you could have a moisture problem stemming from poor insulation.

attic insulation costWhat Does Attic Spray Foam Installation Entail?

After you receive your quote and are prepared for the project to begin, the first part of the project will start when a crew comes to your home to remove the old insulation in the attic.  The older insulation must be removed for the spray foam to effectively work.

The crew will go into the attic and lay down plastic and use a vacuum system to remove the old insulation. The crew then takes the old insulation away to make sure it is disposed of properly.

The next day of the project, a crew will come to your home and run a hose up to the work area in the attic. The majority of the second day is spent spraying the foam onto the roof deck or attic floor depending on the job. A thin layer of foam is also sprayed on the studs of the roof to stop thermal bridging.

Thermal bridging, also called a cold bridge or heat bridge, is an area of a building which has a significantly higher heat transfer than the surrounding materials resulting in an overall reduction in thermal insulation of the building.

Thermal bridging is most commonly found on the studs of exterior walls, attics, and roof structures.

Once everything has been sprayed, the crew cleans up the area so it looks just like it did before the project was started.

Which is More Efficient – Insulating the Floor or Roof Deck of the Attic?

The question we get the most is whether the homeowner should insulate the floor or roof deck with spray foam? We recommend the roof deck is insulated with spray foam because we prefer the unvented system. It’s more efficient and it’s safer we feel in the long-term.

The type of attic system you want is ultimately decided by what you want to do with the space. For people who feel like they need that extra storage or just don’t want to take the risk of moisture buildup, the unvented system is the way to go.

A higher pitched roof lends itself to a vented system and will still reduce the air leakage in the home.

What Services are Included When Insulating an Attic?

The best insulation companies should offer services that start with the call for an estimate and end with you living in a more comfortable home. Some of the services that should be included are:

  • A free estimate for the project.
  • Free concierge program so someone stays with you throughout the entire project to answer any questions you may have.
  • Help with applying for financing1 for the project.
    1 With approved credit. Call for details, 866-900-3626.
  • Cleaning out old insulation from the attic and disposing of it properly.
  • Clean-up after the project is complete so your home looks just as it did before the project was started.
  • Applying for rebates so you get money back on your project.
  • A lifetime warranty that is connected to the house.

Keep heat on the roof surface with spray foam insulationA Guide to Efficient Attic Insulation

The first step to a proper insulation of spray foam in an attic is to seal off the envelope by insulating the top of the house.

The best insulation system for an attic is to spray open cell foam on the roof deck of the attic – which is the underside of the shingles. There are several reasons why this is more efficient:

  • It stops all air and moisture from coming in through the roof.
  • It protects your roof.
  • It will make you attic the same temperature as the rest of the house so the furnace doesn’t have to work as hard to maintain a constant temperature.
  • Heating the attic for homes in Michigan with steeper roofs can help the air flow in your home. Think of a lava lamp and the way the wax rises to the top when it is warm and sinks back to the bottom as it cools down. Air moves the same way as it heats up and cools down.

Another proper insulation solution for the attic would be to have spray foam insulation put on the floor, much like a traditional system. The drawback to this system is you would also need attic venting with baffles in your soffit. This will allow airflow into the soffit. You would also need ridge vents running along the roof deck so the airflow can circulate.

This method is not usually recommended by good contractors because the ventilation must be kept up, the insulation must be properly placed and aligned, and it can’t be obstructed in any way. The entire system is contingent on the airflow getting in and then getting out.

Added Protection Against Drafts and High Energy Bills

Sometimes cold air moving through a crawl space or attic can contribute to the discomfort you are feeling in your home, but sometimes there is more to the discomfort you are feeling.

Insulating your entire home using injection foam and spray foam can make a difference year-round, not only keeping you cool in the summer and warm in the winter, but also saving you money on your energy bills.

Additional Fees, Taxes and Costs

A good contractor won’t hit you with hidden fees and costs once the job is complete. The estimate you sign and agree to should be the final cost of the project.

Getting Started with a Free Estimate

When you are ready to schedule a free in-home estimate give us a call at 866-900-3626, or fill out the form on our website. You can also check out our budget calculator to give you a rough idea of the cost of your project.

Insulation Budget Calculator


About Amanda Ringler

Amanda previously has worked as a breaking news and crime reporter, TV news producer, and editor in Flint and Detroit. Throughout her career as a journalist, she has won several awards from the The Society of Professional Journalists - Detroit Chapter and the Michigan Press Association. As part of the RetroFoam of Michigan family, Amanda uses her experience as a journalist to write content that will help educate homeowners on the benefits of foam insulation. When Amanda isn’t writing, she’s spending time with her husband and rescued huskies. She also loves knitting, making art, cooking, and hosting dinner and a movie night for friends and family.