Attic Insulation – Do You Have Enough?

July 30, 2011

rockwool1Proper attic insulation can make a drastic impact on your utility bills. Any home over 5 years old should have the attic insulation evaluated as settling insulation and higher summer temperatures  can degrade its ability to protect your home from the summer heat.

7 reasons to be concerned about the condition of your attic insulation.

  1. High utility bills.
  2. Its been more than 5 years since the house was built.
  3. You have lived in the house for more than 10 years and never evaluated it.
  4. Some thermal insulation materials settle more than others.
  5. Increasing summer temperatures require more insulation.
  6. Recent contractor activity in the attic  (i.e. telephone, CATV, Security, HVAC). These workers can matt down the insulation while performing their job.
  7. Rodent infiltration. These buggers will easily pack down the insulation to get to various points of interest.

Acceptable attic insulation 10 years ago is not the same as it is today. In fact, in just 3 years, my region has been increased from an acceptable value of R31 to R38.

The Inspection:

  • Determine how much insulation is required. Use this Insulation Chart to determine how much is enough.
  • Enter the attic with great care. Attic entrances may be through a door or attic stair case or possibly a hatch in the closet. WARNING: You must keep your feet/body on the wood joists (beams) as stepping on the sheet rock will cause damage, and possibly cause you to fall through the ceiling.
  • With a flashlight and yard stick: Randomly check the depth of the material. Ensure the measuring device (yard stick) touches the sheet rock and measure to top edge of the insulation material. Try not to crush the insulation while performing the inspection.
  • Determine the type of insulation.  Different material have different R values.

rockwool3If you can see the ceiling joist as in this picture, you  probably do not have enough insulation.  Typical ceiling joists can range from 2 X4’s, 2X6’s to 2X10’s.  For instances, if you have 2X6 beams with loose fill rock wool, you would have a R value of 16.5 (3.0X5.5″=16.5). Newer houses typically have larger beams. Determine the material type as this will help in figuring out how much insulation to add. Use the chart below to calculate the R value of the existing insulation. TIP: If you find you have enough insulation in areas that have not been disturbed, but you find areas matted down due to activity or construction work. Use a soft plastic rake to fluff it back up.

Insulation Table

Common Types of Insulation in Residential Attics

  • batt insulationFiberglass: Comes in batts, blankets, and loose fill, either pink, white or yellow in color. Fibrous in nature and can leave you with microscopic splinters. TIP: Before working with fiberglass insulation, spread a heavy coat of baby powder over any exposed skin, this will fill your pores briefly while working with the material.
  • rockwool2Rock Wool (or Mineral Wool):Loose fill used aggressively prior to 1970. Usually brown or dark gray in color.
  • Cellulose:Loose fill made of recycled paper. Blue or gray in color. With close inspection you will find small pieces 100_0550of newspapers. The product is treated with a fire-retardant solution for safety.
  • Combination:This is not a type, but you may find a combination of two or all three types. Previous owners may have added insulation over the life of the house. This is not a problem, but you should determine how many inches of each type to calculate the value of the existing insulation.

By now, you should know, how much insulation you have vs. what you need. Assuming you need to add insulation, HomeownerBOB highly recommends hiring a professional for this task even though the home centers will provide you tools to perform the work. Once you determine what type of new insulation you prefer, you can easily bid shop the work over the phone.  The professional will need to know 1) square footage of the house, 2) type of insulation material you would like, 3) how many inches to apply.

So how do you determine what type of insulation to use? Read my article on “The Choices“.

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Attic Insulation – The Choices

September 20, 2009

batt insulationAccording to the US Department of Energy, as much as 45% of a home’s energy loss is through the attic. Furthermore, 80% of homes built before 1980 suffer from inadequate insulation

A friend of mine was looking to buy a house recently, he asked me to come by and check it out. It was apparent the owners of the house were fairly interested in reducing their electric bill. Most all of the light fixtures were using CFL’s, they were using a set back thermostat and they had recently replaced an exterior door with one that was Energy Star rated. But what really shocked me was my trip to the attic.  Three  things, 1) they had sprayed radiant barrier paint on the roof decking but 2)  there was less  than 3 inches of insulation in the attic and 3) the air conditioning ducts lacked adequate insulation requiring the HVAC unit to work extra hard to provide the conditioned air throughout the house. I’m not knocking the radiant barrier (I’m a believer), but even most of the radiant barrier folks will tell you to increase you attic insulation first. There are good reasons why HVAC  installers sometimes throw in insulation or RB as part of their package… it works and it also reduces the strain on the HVAC. Blown in insulation is cheap and it can be added in a mater of hours.

Attic Insulation is best applied as blown in loose fill when you need to add  more to an existing home. The product will reach into every nook and cranny, is easy to apply (with the proper equipment), and has instant results. The best way to determine the amount of insulation needed is to refer to this US. DOE  site as it will provide the recommended R-Value down to the zip code.

Making the choice

What is the difference between the attic insulation products and why is one better than the other? If you spend any time looking at the comparisons of the products you will find advantages and disadvantages in all the of them. Its very easy to get caught up in the data, in fact some make a point in overpowering the consumer with too much data. The following chart reflects the most popular products and comparable characteristics that most consumers can understand and recognize value in them. This comparison is for blown-in type insulation only, and these products are typically the most popular. 

 Insulation Table2

 Concerns associated with the compared products:

Rockwool: Rockwool insulation has been classified by the US Gov. as a class 2B carcinogen with   “possible” evidence but lacked conclusive results to be considered a “probable” contributor as a cancer causing agent in lab rats. Additionally, chards of the material will cause skin irritation much like fiberglass. It was very popular prior to 1970 and with some limited concern is still used as an insulation product.

Fiberglass: Fiberglass insulation has been shown to reduce its effectiveness during both high and low temperature ranges (due to convection heat loss), potentially reducing its effectiveness by up to 50%. Even though fiberglass chards can easily irritate the skin, once installed, little risk to the homeowner has been proven. However, the US Gov. has recognized fiberglass as a carcinogen, the levels have been shown to be too low to impact the homeowner.

Cellulose: Cellulose has become recently popular due to being composed of  recycled paper products. Cellulose is heavy compared to the other two and the added weight in the attic may cause standard 1/2″ sheet rock to sag or droop when applied to ceilings with joists spaced at 24″ centers. Additionally, since Cellulose will retain water, moistened by a roof leak may cause the  sheetrock to prematurely fail. Even though the product is treated with chemical flame retardant (generally with a lifetime guarantee), additional care should be exercised by providing adequate space around recessed light fixtures, chimney flues, water heater and HVAC vents.

The blown-in insulation business is fairly competitive and you may find (as I did) that hiring a professional is about as cheap as doing it your self. HomeownerBOB recommends the professional route. The difference in the choices are fairly close, cost may be the most important factor, on the other hand it might be the environmental impact. Either way, make the decision, you will be happy with the results.