Background Insulating is the process by which a fire resistant material is installed at the perimeter or outer envelope of the structure to act as a barrier – to create a resistance to heat flow. This produces a more controlled interior comfort climate and conserves energy. The primary characteristic that is desired in an insulating material is the ability to trap a gas to increase the resistance to heat flow. Physically, the efficiency of the insulating material increases as either the bulk of the air entrapped is increased or the movement of the gas is decreased within a given volume of insulating material.
The measurement of insulating effectiveness is called “resistance to heat flow” and is expressed as “R Value”. Each manufacturer is required to label his materials with its resistance to heat flow at 75 degrees mean temperature (R Value). R Value is a number rating system. As R increases, the overall effectiveness of the insulating material increases. Caution – Insulation may not cover an entire surface. Its R Value must be averaged with other assembly material to give a true total average R value. Minimum R value are established by the State Energy Code. The commonly used fiberous insulating materials are mineral wool, fiberglass and cellulose. These materials are selected for their large ration of surface area to mass of the material in order to better entrap air. The normal form of the insulating material is either the blown loose material, as is most often used in the ceiling, or the batt form.
Other forms are rigid materials such as polyurethane or polystyrene, which are usually supplied in panel form or are sprayed in their application. Air infiltration can be further minimized by the installation of weatherstripping and caulking. Both require owner maintenance throughout the life of the home. Some infiltration will occur under certain temperature and wind conditions. The system of electric boxes and wiring on exterior walls produces an air flow passage whereby the cold or outside air can be drawn through the outlet into the room under most heating conditions, since the outside of the home is at a higher pressure than the inside. Also, venting for fans will produce some air flowage. With acceptable building practices, this situation is virtually unpreventable, as are certain other situations resulting from many openings that do not exist in the home under normal construction.
Moisture in insulation causes it to lose its insulating value. Therefore, vapor barriers are put on the inside to keep moisture from entering into the walls and ceilings. It is also important to properly vent the attic to create airflow. This can be accomplished with roof vents, gable louvers, ridge vents and soffit vents. Cathedral ceiling areas, where there is no attic, requires proper ventilation. Year round ventilation is necessary. Insulation and ventilation performance standards in some locations are specified by Code. You may wish to refer to the Moisture Standard for additional information. With the above background on the insulation material in mind, the following are the most common problems occurring in the area of insulation: Common Defects or Problems:
Performance Standard – Drain, waste and vent, and water pipes shall be adequately protected, as required by applicable code, during normally anticipated cold weather, and as defined in accordance with ASHRAE design temperatures, to prevent freezing. Builder Repair Responsibility – Builder will correct situations not meeting the code. It is the homeowner’s responsibility to drain or otherwise protect lines and exterior faucets and hose bibs (even if they have an anti-siphon valve attached) exposed to freezing temperatures.
Craig’s Comments: Insulation should be installed behind, or to the outside of, pipes located in outside walls. With batt insulation, this can be difficult to do and still get the full R-value along with no gaps. Some insulation contractors take the time to do it right, others just stuff the batt in making the pipe outside the insulation and exposed to cold winter temperatures. Alternative insulations (other than batts) such as blown cellulose and spray-in-place foam do a much better job of getting insulation behind and tightly around pipes, and electrical wires. Another way to help prevent freezing pipes in outside walls is to not put them n the outside walls in the first place. Design the home so the pipes are on inside walls.
2. Common Defect or Problem – Moisture condensation on windows.
Performance Standard – Moisture condenses on the window since it is the coldest object in any given room with the glass having a much higher rate of heat transmission and hence, being the colder surface during the normal heating season. Moisture condensation on windows is an indication of either too much moisture in the room, or poor circulation of the moisture that is present. The owner can minimize this condition by merely opening a window to permit the excess moisture to escape or by installing a dehumidifying system if the condition persists. It should be noted that in homes with humidification equipment, the formation of moisture on the windows is an indication that the humidifying equipment is set too high and producing too much moisture. It is also recommended that screens be removed from casement windows during the heating season. Builder Repair Responsibility None, except to explain to the owner more thoroughly how this condition is caused.
Craig’s Comments: Condensation on windows in the winter can also be caused by faulty windows. Properly functioning, code-required windows should not have condensation on them except possibly when it is very cold outside, or the inside air is too humid. Unvented gas fireplaces and improperly vented clothes dryers can easily cause high humidity levels. Look at my other information on window condensation.
3. Common Defect or Problem – Drafts at baseboards.
Performance Standard – The juncture of the floor and wall system is conducive to openings so a certain amount of draft is permissible, although it should be minimized. Builder Repair Responsibility Check out the areas to assure the air leakage is at a minimum.
Craig’s Comments: Drafts at baseboards should not exist. Code requires that infiltration sites be sealed, and this is a major one. Problems associated with leaks at the baseboards include insects and staining of carpeting along the walls. Techniques used by many bulders to seal this joint include caulk or construction adhesive between the floor sheathing and the wall bottom plate. A small foam pad or gasket called a sill sealer is also a common way to seal that joint. After the house is completed, in many cases the joint can be caulked from the inside.
4. Common Defect or Problem – Drafts from electric outlets.
Performance Standard – Electrical junction boxes on exterior walls may produce airflow whereby the cold air can be drawn through the outlet into a room. Builder Repair Responsibility Check out the areas to assure the air leakage is at a minimum.
Craig’s Comments: Drafts from electrical outlets indicate infiltration problems. The problem can be especially bad when exterior outlets fall in between the same two wall studs as an interior outlet. Per code, infiltration locations should be sealed. This includes electrical outlet boxes in the interior wall. Proper insulation installation and sealing of top & bottom wall plates helps reduce the drafts. If at all possible, do not put an interior outlet in the same stud bay as an exterior outlet. Foam gaskets are available to help reduce the drafts in existing homes.
5. Common Defect or Problem – Drafts from recessed lights, ceiling fans, vent fans.
Performance Standard – Drafts in these areas are normal.. Builder Repair Responsibility None, as long as there is proper insulation around the unit
Craig’s Comments: Drafts in these areas are not normal using today’s codes. These drafts can lead to staining and mold growth. Code requires that these areas be sealed since they are infiltration sites. Caulking from the attic side will solve most of the problems. Air-tight recessed lights are available, and according to my interpretation of the code, are required. In any case they should be used. (This is not the same as an “IC” or Insulation Contact rated recessed light fixture.
6. Common Defect or Problem – Drafts around doors and windows.
Performance Standard – Doors and windows are cold spot sources and some infiltration of air must be expected. Proper weather-stripping and insulating around these areas can minimize air passage. However, depending on the type of window (i.e. double hung and sliding windows will have more air infiltration than casement or stationary windows) and under certain temperature and wind conditions, some infiltration will be observed by the homeowner. Builder Repair Responsibility Builder to inspect and adjust poorly fitted weather-stripping. If draft comes around casings, builder to make sure insulation is in place around window wherever possible.
Craig’s Comments: New windows and doors are very tight compared to older windows. They will leak a small amount, but it should be very difficult to feel. If you feel a draft around a door or window under anything but a high wind, and the door or window is properly closed, something is wrong. Make sure though, that what you are feeling is outside air leaking in rather than air coming from a heat register or from a ceiling fan.
7. Common Defect or Problem – Blown insulation in attic displaces.
Performance Standard – This may occur due to wind and air movement in the attic. Builder Repair Responsibility During the first year, builder to redistribute insulation to Code.
Craig’s Comments: Insulation baffles installed in the attic over the outside walls provides an air space for air to go from the soffits past the insulation to the attic. Sometimes these baffles are left out, which lets wind blow the insulation around. An over-vented attic will have more problems with insulation being blown around. I do not like vented attics, and unvented attic do not have this problem.
8. Common Defect or Problem – Blown insulation in attic settles.
Performance Standard – During the first year insulation should not settle. However, after time, settling will occur. Builder Repair Responsibility Builder to correct during first year.
Craig’s Comments: Blown insulation will settle. Some of the higher density insulation will settle less, but blown insulation typically settles. Insulation manufacturers label their insulation with a settled R-value as well as a density. Some unscrupulous insulation installers “fluff” the insulation by blowing it with lots of air. This creates a thicker layer of insulation using fewer bags, and results in insulation that does not have the required R-value and will settle.
9. Common Defect or Problem – Not enough insulation.
Performance Standard – The builder must provide the R rating as specified by Code or contract. Builder Repair Responsibility Builder to correct to Code/contract.
Craig’s Comments: Insulation manufacturers specify a density and/or thickness necessary to get a certain R-value. Installers are required to put tags or labels in the attic showing manufacturer, thickness and R-value.
10. Common Defect or Problem – Gaps at the top of batt insulation.
Performance Standard – There should be no gaps. Builder Repair Responsibility Builder to insulate or foam spaces.
Craig’s Comments: I will add that there should be no gaps ANYWHERE in the batt insulation. Not at the top, bottom, in between batts, or around pipes and wiring. This is best checked before wallboards are put up, when the wall insulation is still visible. Cathedral ceilings are the same way.