Seal Air Leaks
Hidden air leaks cause some of the largest heat loss in old and new homes alike. Air leaks can also result in condensation, mold, building degradation and ice dams. Common air leakage sites include:
- Plumbing penetrations through insulated floors and ceilings
- Chimney penetrations through ceilings
- Fireplace dampers
- Attic access hatches
- Recessed lights and fans in insulated ceilings
- Wiring penetrations through insulated floors, ceilings, and walls
- Missing plaster
- Electrical outlets and conduits
- Window, door, and baseboard moldings
- Dropped ceilings above bathtubs and cabinets
- Top plates in attics
- Un-blocked floor joist connecting an unconditioned attic with a conditioned floor assembly
- Leaky ducts running through an unconditioned attic or outside wall
- Leaky cantilevers
- Leaky rim joists
- Improperly fire-stopped fireplace chases
In many cases, homeowners replace a roof, increase ventilation, add attic insulation and replace a standard furnace with a high efficiency closed loop furnace and wonder why energy consumption is still high and they suddenly have condensation problems in their attic that they never had before. High efficiency furnaces cause indoor relative humidity to go up. The increased attic ventilation can pull more moisture laden air through the unsealed thermal bypasses in the attic. The insulation makes the attic colder and warm moist air condenses. The condensation and frost is usually heaviest directly over large thermal bypasses.
HEC Technologies understands the importance of sealing large thermal bypasses before insulating. Sealing all of the small leakage points is also a good idea but usually involves removing existing insulation, sealing and re-insulating. This increases performance and minimizes problems but also increases costs. We usually present the homeowner with the option.
Insulate
Insulation is your primary defense against heat loss through the building envelope. However, putting insulation into a house after it is built can be pretty difficult. Hiring a knowledgeable professional is usually a prudent idea.
- Attics and Walls
Where do I start? Your priority should be to insulate un-insulated areas like walls, rim joists and crawl spaces first. Then you should consider adding insulation to poorly insulated areas like the attic. Try to think of it this way. If you went outside on a cold day with no clothes on except for a hat, I doubt you would run back in the house for a second hat. You would cover the unprotected areas of your body first. The same logic applies with a house. Cellulose and foam are very good choices of insulation materials depending on the application. Fiberglass batts and blown fiberglass perform poorly in almost every application. - Basements and Crawls.
Materials that could be damaged by moisture such as fiberglass and cellulose should not be use on outside foundation walls below grade. Spray-on, closed cell polyurethane foam is a far better choice for a variety of reasons. If you are finishing a basement, foam does need to be protected from fire by drywall or an approved ignition barrier.
Crawl spaces should be sealed not ventilated. Earthen floors should be covered with 6 mil poly vapor barrier. Adding drainage and covering the poly with concrete is even better. Many moisture problems and health issues start in damp crawl spaces. Walls, rim joists and mud sill should be sealed and insulated with closed cell spray-on polyurethane foam
How to Find Air Leaks
HEC Technologies starts with a thorough knowledge of framing techniques and building science. Visual inspection, infra red cameras, blower doors and smoke pencils are used as needed to reveal a multitude of problems that a home owner or poorly trained insulation technician would never find. Dirty spots on painted surfaces, carpeting and fiberglass insulation can also be telltale signs.