Residential Attic Insulation
Effective the first of January, 2012 the State of Texas has adopted and supposedly will begin enforcing the 2009 International Energy Conservation Code (IECC). It is hoped that the implementation of this code will "result in the optimal utilization of fossil fuel and nondepletable resources in all communities, large and small". (Quoted from the Preface of the 2009 IECC.)
This photo was taken recently in an area where this new code standard was in effect. What you see is a manufacturer’s label on the inside of a pull down, folding attic access ladder. It is clearly labeled with its R-10 value. This is much, much more than most homes have but nowhere near enough to meet the current standard for new construction.
Some Texas communities actually adopted this code before the state did but it is now in effect statewide regardless of its adoption by local authorities. And yes, it does apply to unincorporated areas but only to new construction. There is no requirement to bring an existing home up to this standard. Depending on how old a home is it may be virtually impossible if not financially impractical to try and do so.
The IECC covers a lot of things which the average home owner probably does not understand and would have no way of addressing even if he does. For instance new homes are required to be sealed much tighter than older homes. The new standard is no more than 7 ACH or "Air Changes per Hour". This means a lot of extra caulking and sealing goes into spaces during construction that will never be seen again after completion. Trying to seal up an older home to this standard would be very difficult indeed.
There are other standards put forth in the IECC that are just as difficult for a new home buyer to understand or verify but a few are more obvious and easier to verify and not impossible to retrofit into an older home. I’m mainly talking about attic insulation. This is pretty easy to see and to know if it is done right if you know what to look for.
The IECC requirements are divided up according to climate zones and what is required in one area can be quite different in another. As I live and work in the Southern coastal area of Texas my comments are directed to homes in that area. This area is classified as “warm and humid” so North and West Texas have different needs.
Getting back to attic insulation, in most of South and East Texas the minimum R-value for attic insulation in a ventilated attic is R-30. R-value varies from one product to another but a useful “Rule of Thumb” for figuring the R-value of your insulation is to measure the depth in inches and multiply by 3. This is not perfect but will get you real close. Most homes that were built in the last decade will have a form stapled up in the attic that was filled out by the insulator at the time of construction that will give you more details. The R-30 minimum has been in effect for several years but there are some changes to the application that you should know.
In the past the area under your attic mounted A/C & heating equipment and water heater were allowed less insulation. Also, the area over the attic access door has largely been un-insulated and ignored. This is no longer true. Per the new IECC standards the area under attic mounted equipment has to have the same R-value as the rest of the attic. This means the equipment has to be mounted on a higher deck so the insulation underneath is not compressed. Compressed insulation loses R-value.
Another tricky area that builders are having difficulty dealing with is how to insulate the attic access to the same level as the surrounding area in the attic. This applies whether the attic access is a pull down folding ladder, a hatch or scuttle in the ceiling or a walk through door in an upstairs area. They also have to do it in a way that does not allow insulation to spill out when you open the access. You should be able to see very easily if your attic access is insulated to the “same level as your attic”. Note that last phrase in quotations. Whatever R-value is installed in the attic floor whether it be the R-30 minimum or more that same R-value is to be applied to the ceiling mounted attic accesses.
Wall mounted accesses (doors) into the attic have a slightly different standard as they have to be insulated to the same level as the surrounding area. In this area, wall R-value minimum is still R-13. That has been true for many years as this is typically the R-value of 4" batt type insulation which is used commonly in between the 2 x 4 studs of most homes. If the R-value in your attic walls is greater than R-13 then the access door to that attic has to be insulated to the same R-value as the surrounding wall.
Just so everyone will know, insulation is required between air conditioned and non air conditioned spaces only. There is no requirement to insulate over a garage for instance. Likewise, there is no need to insulate the interior walls of a home. Now, if the interior wall in one room is taller than in another room and extends up into the attic space, that portion of that wall is to be insulated.
Posted: Jan 21, 2012
Posted by: Ed Fryday, ACI, CMI® | TREC License: #6932
Space City Inspections, LLC