As you will quickly learn, there is more to an attic inspection than simply sticking a poking ones head into an attic and taking a peak.

How do I evaluate my attic insulation?

This section of the web site is for the professional and individual who want more than a cursory understanding of insulation problems.  More specifically it is for the remodeling contractor, HVAC technician, professional home inspector, and the truly interested homeowner.  It is much more technical in nature than the rest of the web site, so people can make informed decisions about attic insulation. 

As you will quickly learn, there is more to an attic inspection than simply sticking a poking ones head into an attic and taking a peak.  We will show the areas where we routinely find problems and then explain proper repair methods. 

The inspection

The best way to determine if you have enough insulation is to inspect it.  This can only be done in the attic.  Advanced Insulation provides the information and insights to make a thorough inspection and determination, if you need more attic insulation. 

    
Photo of a salesman / inspector   Photo of blown rock wool tapering down to bare sheetrock
climbing into a attic through
an attic access.

If you are unable to get into your attic, we also provide free estimates and one of the services we offer is an infrared scan.  You can also ask your HVAC contractor to perform a physical inspection, when they are out servicing your air handler. 

A visual attic insulation inspection is much more informative than the infrared scans we perform.  Infrared scans are only effective when there is a significant temperature difference and uneven insulation.  I’ve done infrared scans of attics that looked fine, but were missing 50% of the attic insulation.  The 50% that was there was installed evenly, so the infrared camera did not tell the entire story. 

We caution anyone going up into an attic to be careful.  We have received calls from consumers who have fallen through their ceilings while working up in their attics.  We use headlamps to keep our hands free which helps reduce the potential for a fall.  The heat in an attic can be hard on an individual if they are not used to it. 

How much insulation or R-value do I need?

The majority of blueprints for new construction either call for an R-30 or R-38.  Fiberglass batt manufacturers typically sell batts for attics at either an R-30 or R-38 value.  This is why these are standard R-values we see specified on blueprints.  

The International Energy Conservation Code calls for an R-30 in the desert communities and an R-38 in Northern Arizona.  These R-values are adequate.  It is our opinion that if a house in Phoenix Metropolitan area has asphalt shingles, we’d recommend an R-38 because these attics run so much hotter than attics with tile roofs. 

At Advanced Insulation we believe that a quality installation is the key to realizing specified R-value.  Just because a builder, an attic card stating R-values or a set of blue prints say and attic has an R-30 or R-38, doesn’t mean that is what a house really has.  The key is to make sure you got what you paid for, be it an R-30 or an R-38 and this is why the inspection process is so important.  The common problems we outline in this section of the web site are the thermal defects that erode your R-value, efficiency and comfort. 

Why is quality of work so important?

The lack of quality control and meaningful inspections has made quality attic work the exception and not the rule.  Quality “installation” of the insulation material is critical to achieving the rated R-value. 

One of the key things to remember when inspecting attic insulation is that what appears to be a small insulation problem, what we refer to as a thermal defect, can have a disproportionate impact on R-value. 

Pause for a moment and ask yourself the following question.  What is the impact on R-value when the attic has five percent missing insulation?    The answer to this question is crucial to understanding why quality is so important in insulation. 

A simple example is a 2000 square foot house with 5% or 100 square feet of missing insulation.  The question is how much does a five percent missing insulation impact the overall R-value of the attic?   The impact is huge.  The R-value is degraded by 50%. 

Do I have access to inspect?

To perform an insulation inspection you need to have access into the attic.  Some homes have a combination of areas that are difficult to access and other areas that are wide open.  It is common to see the tight areas insulated with fiberglass batts and the open areas blown because it is less expensive to blow an attic than it is to batt it. 

There are also “Santa Fe” style homes, contemporary homes with flat roofs and certain types of vaults that do not permit any access for inspection.  These are the types of attics that we recommend beginning with an infrared scan and an evaluation of your utility bill, if you suspect a problem.  If there are problems they can be fixed, but these types of repairs are often much more costly than conventional attics.

Complicated Homes 

Occasionally, Advanced Insulation reserves the right on larger more complicated homes to charge for evaluations and estimates.  These homes are typically over four thousand livable square feet, have multiple ceiling heights and are difficult to access.  On these types of houses it can easily take a half a day to inspect them and come up with an action plan to repair them correctly.  This is why we reserve the right to charge for the assessment.  The amount depends on the size and complexity of the house, but averages about two hundred dollars.

The architectural community has designed tens of thousands of homes without any thought on how to properly insulate them.  We know because every week we read their blue prints when generating quotes for new construction estimates.  They lack the details and forethought that would suggest consideration for the thermal and pressure envelope. 

The Standard Attic Insulation Problems

There are about ten common problems that you need to focus on when inspecting attic insulation.  In this section we provide a description of each of these common problems and a photograph to accompany the description. 

Out in the field we see variations of these problems and we cannot document each variation.  The important thing to note is that the thermal envelope or insulation system must have integrity, if you are going to realize the optimal R-value.  When we inspect, we look for the “thermal defect” that undermines insulation performance.

Blown insulation problems

The most common problem we encounter in the field is with blown insulation.  This is because so few attics over the past fifty years have actually been inspected after they are blown.  During the past fifteen years, we rarely have found attics with blown in insulation that deliver the specified R-value.  We’ve literally inspected hundreds of attics missing as much as 20% - 50% of the blown-in insulation.  In other words, these attics were never done right to begin with!   To understand why problems are so persuasive, read the following link: why so many problems.

At Advanced Insulation we prefer a blown-in insulation to a fiberglass batts installation because when done right a blown-in insulation does a better job than a fiberglass batt.  A blown material conforms better to the framing, wiring, recessed light cans and plumbing.  The Achilles heel of blown in insulation is that it is more subject to sloppy workmanship and fraud. 

In homes built between the early 80’s to the early 2000s we have seen blown attic insulation work that is literally out of control, as indicated by the two photographs.  These two different attics were insulated in the 90s.  The material is not the problem, it is the culture of the building and insulation industry at the time the work was done. 

  
Missing cellulose insulation     Missing cellulose insulation over at master bathroom.
See recessed light fixture,       Bathroom fan prominently featured in photo.
fiberglass batt and bottom
chord of truss

At Advanced Insulation we believe there is no excuse for this type of work and yet it was not uncommon during the time period.  In the early 2000s the threat of construction defect litigation forced many builders to treat insulation with more regard.  The threat of litigation exerted pressure on builders, who in turn began to hold their subcontractors to higher standards. 

In older homes that were most likely built in the 60’s or early 70s an inadequate amount of material was installed on day one.  Notice that we can see all the bottom chords or joists in the photographs.  This is not an issue of the insulation settling.  The old cardboard colored cellulose in the right hand picture would have settled approximately 20% and the rock wool in the photograph on the left would have had a negligible amount of settling.  These low depths are a sign of the times, a time when energy conservation was not a consideration. 

    
Exposed 2x4 framing members                 Exposed 2x6 framing members

The framing members in these two photos are typically 3.5” or 5.5” high and if you can see them, you can immediately assume that there is not enough blown in attic insulation.  When we inspect attics we immediately determine the height of the bottom chord or joist and then use them as a depth gauge as we scan the attics with our headlamps. 

Determining R-value of blown-in insulation

To determine what the approximate R-value is of your blown in attic insulation you need to establish an average depth and then consult the chart below to determine an approximate R-value.  The goal is to make an informed estimate of R-value based on the inspection.    

Example – I measure 5” of existing cellulose insulation, which means that I have an R-18.5 (5” x 3.7).  To get an R-38 or a little better, I would add an additional 7” of cellulose which would settle to 6”, which would provide me a total R-value of R-21 of new insulation.  Couple the R-21 with the existing R-18.5 and now the R-value is 39.5.

Attempting to determine an average depth and R-value can be an exercise in futility in some attics when the depths range from bare sheetrock all the way up to the proper depth.  If you have areas below five inches and areas where there is bare sheetrock, the determination is simple – you need more insulation.

The second issue you are looking for is poor installation of blown insulation.  The farther away from the attic access the more likely the problem.  This means that simply sticking your head up into the attic and visually inspecting the insulation while standing on a step ladder is ineffective.  A thorough attic inspection can be hard work given the lack of headroom in some of these attics.

The point you need to remember is that the harder it is to access an area to inspect it, the greater the chance that there will be a problem because the insulation installer had to deal with the same obstacles.  On low pitched roofs problems often occur at the perimeter of the building or eve.  Also areas where the duct work blocks access are often prone to problems. 

How much does human error play into missing insulation problems?   Look at the photo below for an answer.  You’ll see a whole room missed, i.e. never blown.  Notice the air distribution system, which indicates a conditioned room below the sheet rock.  We’ve seen houses where the attic insulation was never blown on day one. 

Completely un-insulated attic – notice ductwork in back
ground which indicates conditioned space below

Framing issues in certain homes prevent access for the installer to access a room.  We’ve seen laundry rooms that are adjacent to garages that installers assumed were part of an un-insulated garage.  We train our installers to walk around a house before they blow it, so they don’t get disoriented up in the attic. 

In most cases you’ll know pretty quickly if you have a problem with the blown insulation.  It is not that difficult to make a determination.  The key is to venture out into the attic and do a thorough evaluation. 

Kneewall Issues

The second most common problem we find in attics is with kneewalls.  A kneewalls is a vertical wall between the house and the attic.  An exterior wall is a wall between the inside of a house and the outdoors.  Kneewalls typically occur where ceiling heights change or in a skylight wells.

In the desert it is important to remember that when it is 100˚F outside it may be as hot as 130˚F in the attic, so the temperature difference from inside the house to outside might be 20˚F and from the house to the attic would be 50˚F.  Temperature difference drives heat flow, so the rate of heat gain is greater from the attic than it is from the outdoors.  This is why it is so important to have to kneewalls insulated correctly. 

A common example of a kneewall in an older Phoenix home occurs in the hallway where the ceiling height drops to 7’ in the hallway.  In the photo below, notice the bare sheetrock on the small kneewalls created by a change in ceiling heights. 

     
Dropped soffit in hallway                                 Missed kneewalls in as seen in attic

More common in newer homes is where a vaulted ceiling changes to a flat ceiling.  Every time a ceiling height changes it creates a knee wall.  Kneewalls are either missed or the batts start to pull away from the sheetrock. 

    
Un-insulated kneewall                     Un-insulated skylight well

     
Un-insulated kneewall in attic from inside the house           Same kneewall seen with an
                                                                                      infrared camera.

We have come to the conclusion that the best way to deal with a kneewall is to strap a batt in place and better yet to cover it with a reflective product so that hot or cold attic air cannot undermine the R-value of the batt.

Batts falling into dropped soffits

Problematic coffers and arched ceilings

This section could easily be called thermal envelope and pressure envelope misalignment.  Whatever you call it, it is one of the more complicated issues we face in fixing existing homes.  In the photograph below you can see the arch and dropped soffits where misalignment occurs.  What typically happens is that a fiberglass batt is laid over these soffits at the ceiling line.  Although this is a standard detail, it also creates a thermal defect. 

The fiberglass batts do not form an air barrier and they do sometimes fall into the cavities below them if they are large enough because they are only held in place by a friction fit.  The air barrier or pressure envelope is breached because the recessed cans that you can see in the soffits leak air right around the fiberglass batts.

In almost every instance when we view with an infrared camera all of the coffers and arches you see in the photograph below the insulation above them is being bypassed and coffers look colder in the winter and warmer in the summer.  It is a big problem. 

Even worse, in homes with multiple ceiling heights, we routinely observe a situation where the insulation installers decided to run the fiberglass batts along the bottom chord of a truss even when the ceiling drops several feet below.  An example would be a drop ceiling in a bathroom or closet.  When the batt drops down to the ceiling below it creates a significant breach in the insulation system.

This type of failure and its impact of it can be seen in the two pictures below.  In the first picture you can see how a pink fiberglass batt fell about three or four feet to the ceiling below.  This creates a breach in the thermal envelope.  This type of failure drastically reduces R-value and comfort.  The impact on a hot day in Phoenix would be kneewalls glowing hot as seen in the infrared photograph showing interior walls at 95˚F. 

       
Batts falling into dropped ceiling areas                   The result is kneewalls that get exposed to
                                                                          attic temperatures - 95˚F

When a ceiling height changes inside a house the proper way to insulate is to have the fiberglass batt follow the plane created by the sheetrock.  Ideally, we always have the fiberglass batt in contact with the sheetrock.  Unfortunately with dropped soffits it is more difficult to align the thermal envelope with the sheet rock.  The photo epitomizes the challenges we face in fixing brand new homes.

We attempt to create solutions that our customers can afford and make sense.  At Advanced Insulation we are energy pragmatists and not energy purists.  This means we deal with budgets and market realities.  We are interested in saving our customers the most money at the best possible price.  This benefits our customers and the environment.  We acknowledge that there is a point of diminishing returns and sometimes it is not economically feasible to eliminate all the problems.

At Advanced insulation we adopt a variety of strategies to fix these types of problems and discuss them with the customer.  We would prefer to cap these coffers and drops with rigid insulation in the ceiling or fill them with cellulose, but that is not always possible due to budgetary or space constraints. 

Open Chases and framing details

A smaller version of the dropped soffit is the open chase.  Open chases are less frequent, but can create significant problems.  An open chase is best observed in the attic.  It is a framed area that is not capped off and you can actually see down into the house, often all the way down to the floor below. 

    
Fireplace chimney creates chase       No draft stopping at top plate creates
                                                       a chase as seen from the attic.  

The problem with open chases is that they are so narrow that the solution must be applied up in the attic.  Ideally, the chase is capped in the attic with rigid insulation.  This prevents air leakage as well eliminates the insulation problem.

Attic Platforms & Walkways

In some attics it is not unusual to see platforms or walkways that lead from the attic access to the mechanical unit.  These platforms are constructed so the heating and air conditioning technician can easily access the air handler.  The risk of these platforms is that if batts are not installed underneath them or the installer blowing the attic fails to blow under the deck, which results in a thermal defect. 

These pieces of plywood or OSB are nailed right to the bottom chord of the truss.  If the bottom chord is a 2x4 it is best to have a fiberglass batt installed because three and a half inches is a challenge to blow.  A 2x6 bottom chord creates a 5 ½” space that is high enough for an installer to blow insulation under the walk-way, assuming the insulation installer remembers to check. 

Insulation blown away from soffit vents

Light density blown fiberglass insulation at a half pound per cubic foot can be blown away from both eve vents and/or tile roof vents on low pitched roofs. The result is exposed sheet rock and this is the very thing we are trying to eliminate in an attic.

   
Even vent                                                   Wind appears to have blown fiberglass
                                                                  away from vent hole.

Ideally in an attic with eve vents a baffle is used to prevent the air blowing through the vent and into the insulation.  Fortunately we do not come across this style of eve vents that often.  When we do, we include baffles in our estimates.

Poorly Installed Batts

We often see batts installed in such a fashion that they can’t possibly achieve their rated R-value.  The batts are not in contact with the sheet rock and depending on the season either hot or cold attic air gets around the batts, which we refer to as thermal by-pass.  In the photograph below white is warm and you can see how the fiberglass batts have been by-passed

Infrared image of batts failing due to
installation issues.

In situations like this we’ll often blow four inches of insulation on top of the batts, assuming we have access, to deal with all the gaps, cracks and voids that undermine the performance of the batts.  We call this “capping.”

Disrupted Insulation

Although the insulation industry is responsible for the majority of the problems we see in attics, there are others who go up into the attic to perform repairs or upgrade existing systems and it is often at the expense of the insulation system  

Other subcontractors either may not realize the damage they are doing or they simply don’t care.

Over the years we have observed damage done by electricians, carpenters, HVAC technicians, security system installers, and audio installers.  There is often little regard for fiberglass batts. The batts make people itch, so after they move them away from where they are working they don’t put the material back. 

               
Electrician moves blown rock wool away for              HVAC technician moves batt away for install
installation of recessed can and then fails to             a new supply registrar. And then fails to put
push back the rock wool insulation.                  back the fiberglass batt

In the case of blown insulation, we’ll sometimes see the material in areas where work is being performed compressed to the point where a minimum of 50% of the R-value is lost.  These types of insulation problems are more common than people realize. 

Attic Access

If the access into the attic is in a closet or another part of the house, it must be treated as an important part of the thermal envelope.  To gain access to an attic often a piece of sheetrock needs to be moved away from the access point.  It is important that a piece of fiberglass be physically attached to the back of this sheetrock with glue.  If the batt is not secured to the back of the sheet rock, it is not unusual that it is not put back in place when someone has been up in the attic.  Although this detail may seem minor, it is little details like this that compromise overall R-value. 

Context for making insulation decisions

Although we are an insulation company, there are other issues that we consider when we make recommendations for adding additional insulation to a customer’s home.  In this section of the web site we explore why some homes are better candidates for insulation work than other homes. 

Asphalt Shingles    

At Advanced Insulation we take into account the type of roofing system.  This is especially true in the dessert.  Older homes with asphalt shingles on the roof have much higher attic temperatures than homes with tile because the asphalt shingle absorbs heat and conducts it directly into the attic, whereas the tile is back vented and the heat does not have a clear conduction path.  I’ve measured the temperature of plywood in attics that was 167˚F with air temperatures approaching 140˚F.

Older home in Phoenix with asphalt shingles and two turbine vents

Since temperature difference drives heat gain, homes with asphalt shingles see a hotter and longer summer.  In other words, they get hotter earlier in the year and stay hotter longer.  Our experience tells us that older homes with asphalt shingles are often great candidates for retrofit insulation than houses with tile roofs.

Attic Vents

Many people in the building community have a tendency to think attic ventilation rates have a significant impact on air conditioning loads.  This is only true if the attic is under insulated.  Research done by Professor Bill Rose, Research Architect, Building Research Council-School of Architecture University of Illinois, found that “in roof cavity assemblies which are poorly insulated (less than R-10), ventilation can reduce cooling loads by 25 percent.  However when these assemblies have thermal resistance greater than R-25 ventilation has a negligible effect.”  

Older home with asphalt shingle and turbine vent

Recessed Lighting Fixtures

Advanced Insulation often deals with two types of recessed lighting fixtures:   those that permit insulation to bury them, which are called insulation contact (IC) and those that require clearance from insulation.  The latter group consists of older recessed lights and new halogen recessed lights.  The problem with recessed cans that require clearance is that they create insulation voids that undermine R-value and they are leaky.

Recessed can requiring 3” clearance which creates
a thermal defect that undermines R-value

The solution is to either use IC cans or have us install rigid insulation boxes that we install over recessed cans to create a separation. 

Other Compounding Problems

We also recognize that insulation may not be the solution to a high energy bill.  The house is a system and no one product will make a house energy efficient. 

Solar Control

In the desert it is not only the job of insulation to keep the heat out.  East and West facing windows need to have solar control strategies in order to reduce the heat gain.  These strategies can be a glazing that lets the visible light through the window while rejecting the near infrared energy that drives heat gain. 

Duct Leakage

Just as important as insulation, if not more, is leaky ductwork.  When duct work leaks either conditioned air escapes into attics and crawlspaces or on the return side air is sucked out of these spaces.

• Reducing Duct Leakage

It is beyond the scope of this website to get into a lengthy discussion of leaky ductwork, but it is suffice to say that a great insulation job can be undermined by leaky air distribution work.

Photo of leaky return duct taken in an attic, which will draw hot
summer into the HVAC system  and cold air in the winter.

• Duct Blaster Testing

Questionable Solutions

Some strategies being promoted to consumers to reduce utility bills make us uncomfortable at Advanced Insulation.  They cost too much and don’t hold enough promise.  For these reasons we do not sell or endorse them.

Electric Attic Fans

Research has proven that powered attic fans can suck conditioned air out of the house if the ceiling plane is leaky.  Large fans that draw hundreds of cubic feet of air per minute out of an attic, sometimes draw it out of the house through recessed can and other air leaks.

We’ve seen it happen in Phoenix where a customer was sold fans that pulled over 500 cubic foot or air per minute.  These attic fans actually increased the utility bill once they were installed and running.  In this particular house the homeowner had a significant number of recessed cans, which allowed the attic fans to draw conditioned air right out of the house.  Every cubic foot of air drawn out of the house was replaced by a cubic foot of hot outside air that leaked in to replace it.

Radiant Barriers

Radiant barriers are highly reflective materials designed to block radiant heat transfer.  Research conducted at Oak Ridge National Laboratory has shown that the effectiveness of radiant barriers are minimal, if you have proper insulation.  Furthermore the impact of dust storms can drive dust into attics through attic vents and this dust can accumulate on the radiant barriers installed on an attic floors and thus reduce their effectiveness.  For these reasons Advanced Insulation does not feel they are an effective strategy.

• Radiant Barrier Fact Sheet