Old house insulation: common problems and solutions

Jeffrey Anderson

There are many reasons people purchase an old house -- character, history, and architectural details are just a few of the motivating factors often mentioned. However, one reason for buying an older home you may never hear is because of their outstanding energy efficiency. That's because old houses are notorious for not having enough insulation unless they've undergone a modern renovation. Even then they may not meet current energy guidelines.

Thankfully, adding insulation to an old structure can be fairly easy, especially when combined with other remodeling projects. In some cases you may be able to increase your home's energy efficiency in just an afternoon.

Does my old house need insulation?

Experienced DIYers and homeowners may be able to tell if their house lacks sufficient insulation by telltale drafts, energy bills, or by simply looking in known problem areas such as attics and crawlspaces. But if you don't fall into one of those two categories or simply want confirmation of your suspicions, consider having an energy audit done on your home. A professional with the proper training and tools can eliminate the guesswork and provide a report about the structure's problem areas and recommended solutions.

In addition to insulation, most energy auditors also look at the energy efficiency of windows and doors, duct work insulation and function, furnaces, heat pumps, hot water heaters, and just about anything else that can affect a home's energy usage. There are professional energy auditors in most parts of the country and some power companies offer the service for a small fee or even free to their customers. It's recommended that your energy auditor have either a BPI or RESNET building analyst certification.

Old house insulation problem areas and possible solutions

Depending on the age of the structure, don't be too shocked if little to no insulation is found in some of these spots:

  • Attic -- The attic is a critical part of your home's outer energy envelope and as such has one of the highest recommended R-values. That value can be achieved by insulation on the floor or between the framing for the ceiling of the floor below. It may also be placed between the rafters or trusses on the underside of the roof assembly. Blown insulation can be an excellent choice for up here if the area is to remain unfinished as it can often be pumped into place by a specialized truck in a matter of hours. Spray foam and fiberglass batts are also often used to increase insulation values in the attic.
  • Exterior walls -- If the inside surface of your home's exterior walls feel cold to the touch during the winter months, there's a good chance that they contain little to no insulation or what's in there has settled into the lower part of the cavity. It shouldn't come as much of a surprise in a very old house as insulation wasn't a big priority back when many were built. If part of your renovation includes removing interior wall finishes, adding fiberglass batts or spray foam to the exterior walls can just become part of the project. The same holds true with changing the structure's exterior siding -- installing fiberglass batts between the exterior framing members and/or adding exterior insulation boards can be done at the same time. But, if you don't have any renovation projects planned for the near future that involve the perimeter walls and the home's exterior siding is wood, there is still a method that can be used to increase the insulation value of those outer walls. Many insulation companies have the ability to drill small holes in the exterior siding that allow blown insulation to be pumped into the wall cavities. When the walls are full, the holes are plugged with the same pieces of wood siding that were removed.
  • Crawl space -- Another spot in older homes that can often benefit from beefing up the insulation values is the crawl space. If this area of your home even has insulation, over the years it has probably fallen in places or gotten torn. Fiberglass batts between the floor joists or around the inside perimeter are the most often used methods for insulating a crawl space.

The government's Energy Star website has a map of the country broken down by region that shows recommended insulation values for the most important parts of your home's outer energy envelope and suggestions for how to achieve them.

About the Author

Jeffrey Anderson has a Degree in English from V.M.I., and served as an officer in the Marine Corps. He worked in Residential and Commercial construction management for 25 years before retiring to write full time. He spends his time writing, remodeling his old farmhouse, and in animal rescue.

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