Missing Insulation

Everyone knows that insulation is vital in keeping the conditioned spaces of a building at a comfortableThis attic hatch has no insulation on the cold (roof) side. It is colder than the insulated ceiling and walls in the room. This building owner is paying for heating the attic., but recieving no benefit temperature. In order to maintain this temperature, a continuous boundary of insulation is necessary between the inside and outside. Insulation that is wet or otherwise damaged will not perform as it was intended. In fact, wet insulation is worse than no insulation. Missing insulation is a far more common problem than most people think. Below, we will briefly discuss the common types of insulation found in the northeast, and some of the problems associated with them.

Cellulose is an excellent product for the insulation of buildings when installed correctly. It is commonly used in attics, and recently has become popular for insulating walls. The problem is that over time it settles, much like cereal, so that as much as 20% of the top an insulation bay is nothing but free air. Not only are you paying to condition this air, but condensation may occur making the other 80% of the wall wet.

Fiberglass Batt insulation is still the most common type used in our area. It has good 'R' values per thickness, and is easily installed, although it is often placed incorrectly. Fiberglass should never be compacted or wedged into tight places. It is not an air sealer. Mice, squirrels and other pests are known to nest in fiberglass and they will also steal fibers to line a remote nest. Leaks and condensation will cause fiberglass to become wet, compromising its 'R' value.

Polyurethane, or sprayed-in-place foam carries the highest 'R' value of any insulation product. It coats the framing members and expands, filling every void. It won't settle like cellulose and becomes a structural component, adding rigidity to walls and roof structures. Closed cell foam also acts as an air and vapor barrier. Insects have been known to nest in untreated foam. It smells bad for a short period as it cures(10 - 20 min).

Identifying Old Insulation
Material Description R-Value
per Inch*
Fiberglass batts Pink, yellow, or white; blanket like 3.0
Loose-fill fiberglass Pink, yellow, or white loose fibrous material 2.5
Loose-fill rock wool Denser than fiberglass, "wooly," usually gray with black specks (some newer products are white) 2.8
Loose-fill cellulose Shredded newspaper, gray, "dusty" 3.4
Vermiculite Gray or brown granules 2.7
Perlite White or yellow granules 2.7
Miscellaneous wood products Sawdust, redwood bark, balsa wood 1.0
Expanded polystyrene board Rigid plastic foam board (may be labeled) 3.8
Extruded polystyrene board Rigid plastic foam board (may be labeled) 4.8
Polyisocyanurate board Rigid plastic foam board (may be labeled) 5.8
Spray polyurethane foam Plastic foam, uneven surface 5.9
Urea formaldehyde foam+ Whitish gray or yellow, very brittle foam 4.0
Asbestos++ May be mixed with other materials; difficult to identify 1.0

* These R-values are for old insulation only. They take into account settling, as well as average R-values for old materials.
+ Urea formaldehyde foam is no longer sold due to concerns about formaldehyde outgassing.
++ If you suspect that you have asbestos, consult a hazardous material specialist before you disturb the insulation.
Sources: PG&E Stockton Training Center, 1993 ASHRAE Handbook of Fundamentals, DOE Insulation Fact Sheet

Excerpted from No-Regrets Remodeling by Home Energy Magazine

When we do an infrared scan of a building, we look at the walls to determine if moisture is present, if air loss is occurring and if insulation is missing or damaged. We can easily see how the insulation is performing without opening any walls or the ceiling because of the difference between indoor and outdoor temperatures. We observe ASTM standard C-1060 Thermographic Inspection of Insulation Installations in Envelope Cavities of Frame Buildings (Re-approved 2003). The standard suggests a delta T (temperature differential) of 10°C (18°F), but we have found anomalies at much lower delta T than that. What is important is that we can find insulation problems and we know where to look for them.

If you have a new building and wish to verify that all cavities were properly insulated, Ashton Thermal can help. If you own an existing building, we can look at it and tell you where things are, and where they should be.