Can I add new insulation on top of old insulation?
Yes, you can add the new insulation on top of old insulation, unless it is wet. If it is wet or appears that the insulation has previously been wet, you should look for the cause and repair the problem to prevent a reoccurrence. Remove any wet insulation; wet insulation can lead to mold, mildew, or even the rotting of your ceiling or roof rafters. Either batt or rolled insulation or blown loose-fill insulation (fiberglass or cellulose) can be installed on top of old insulation. You should not tack down rolled insulation, insulation needs to be fluffy to block heat flow or you will reduce the R-value of the insulation by squashing it flat to tack it down.
What are my options/what types of insulation are there?
- Spray foam: there are two kinds of spray foam insulation; Open-cell spray foam is the lighter, less dense option. It is the cheaper of the two but has less insulating power (lowerR-value). Closed-cell spray foam is denser and more expensive, can provide a bit more rigid support to certain structures and can act as a water vapor barrier, because it is less permeable.
- Cellulose: loose-fill insulation that comes in two types: dry and wet. It ismade of recycled paper, consisting primarily of newspaper but also including some cardboard and other appropriate papers. It is the best environmentally conscious option because it is sourced in the recycling arena, though it is treated before use as insulation. The “wet” option is slightly damp when it is sprayed into the cavity.
- Fiberglass blanket: Widely available and familiar, standard widths and thicknesses are designed to fit between studs, joists, and rafters. Paper- and foil-faced versions have stapling flanges that make installation easy. Best used in walls, floors, and ceilings.
- Rigid board / foam board: form of insulation that’s applied to the exterior of the building. This is especially critical in preventing damage (such as mold and rot) to framing and walls in areas with extremely cold or damp climates.
- Radiant barrier: Radiant barrier sheathingis generally inexpensive and reflects thermal radiation to keep attic spaces cool. Traditionally used in warm climates, these highly reflective materials, such as aluminum foil, are installed on the underside of a roof and reduce radiant heat transfer from the sun.
- Rolls and batts: comes in convenient rolls that are easy to transport and carry. It’s especially suitable for do-it-yourself projects, but take care to cut the material to fit around plumbing pipes, wires, and electrical outlets.
What are the advantages to insulating my attic?
- Save money on energy bill: Whether it’s winter or summer, attic insulation can help save you money by lowering your monthly power bill. Attic insulation does this by stabilizing the temperature in your home and preventing energy loss from warm or cool air that escapes your home. These two factors ensure that your HVAC system doesn’t have to work as hard, which saves you money in return.
- Eco-friendly: Any way that you can make your home more energy efficient reduces your carbon footprint and does your part for the environment. In most homes, the HVAC systems account for more than half of all of their carbon dioxide output.
- Preventing long-term damage from moisture: When an attic is not properly insulated, the rising heat might lead to melting snow on a roof, which can then lead to ice dams. Moisture, ice dams, and condensation can slowly, steadily cause persistent damage in a home, especially on the roof, which can be very expensive to repair. Moisture can also seep inside, and wet insulation is much less effective at keeping in heat. This turns into a horrible cycle of long-term damage. By sealing, checking, and changing out your insulation, you can prevent problems down the road. If you do have condensation or moisture inside your attic, it may be symptomatic of roofing issues or leakage; it’s important to call experts right away to have this checked out.
What is R-value?
Insulation is identified and labeled by its R-value. “R” stands for resistance to heat flow; therefore, the higher the R-value, the greater the insulating power. Different insulation products have different R-values so be sure to read the packaging carefully. Additionally, the R-Value of your insulation can decrease over time as the product ages or settles.
What areas of my home should be insulated?
For optimal energy efficiency, your home should be properly insulated from the roof down to its foundation. In addition to insulation, consider moisture and air leakage control in each area of your house. The most common spaces for energy savings are:
- Attic: heat naturally rises, which means that the attic will hold a lot of the heat generated in the home. During the winter, having that heat escape through the attic will push up energy bills.
- Walls: adding insulation to the walls of a home can reduce the energy needed to heat or cool the space, resulting in lower utility bills. In addition, insulated walls can give residents more privacy as insulated walls do a better job of blocking sound.
- Floors: adding in insulation help protect the heated and cooled air generated by your heating and air conditioning systems. Insulated floors can also help reduce noise, particularly in multi-level homes where residents live on different floors.
- Crawlspace/Basement: Insulated crawlspaces can help retain heat throughout the house, but it can also ensure that pipes and ductwork within the crawlspace can’t freeze, even when outdoor temperatures are extraordinarily low. In a finished basement, insulation can render the room into a suitable living space, adding square footage to the home. Even an unfinished basement can have insulated floors to help retain heat in the home.
For more information: https://energy.gov/energysaver/where-insulate-home
How often does my insulation need to be replaced?
According to the International Association of Certified Home Inspectors (InterNACHI) most types of insulation have a life span much longer than homeowners might think. Housewrap, wrap tape and spray foam last 80 or more years, while loose-fill, foamboard, cellulose, fiberglass, rock wool and loose fill all last 100 years or more. These life spans are all for ideal conditions only, and your home may have less-than-ideal conditions for keeping your insulation in top shape. Any of the following situations could shorten the life of your insulation:
- Settling or Compacting
- Mold or Mildew from Water Leaks
- Material is not Thick Enough
- Outdated Insulating Material has Decayed
- Puncturing the insulation will decrease its effectiveness