Icicles are beautiful. Or are they?
As energy prices rise and the temperature begins dropping we find ourselves think more about how to better insulate our homes. Understanding a little bit about how heat escapes the home is always a good place to start.
As air is heated, it becomes less dense and so becomes lighter. This heated air rises to the highest point of the building envelope where it transfers energy to the colder attic. Remember, heat is energy and energy cannot be destroyed, only moved and heat travels from warmer to cooler areas, not the other way around. Since the attic space is much colder than the conditioned space, it gladly accepts this heated air and it is soon dispersed to the outside. The idea of insulation is to slow the transfer of heat from the conditioned space to the colder, unconditioned space.
Try to remember last winter. Did your house have large icicles hanging from the roof? When you were a kid, icicles were more common than they are now so why is that? Icicles form from the water runoff caused by a poorly insulated/ventilated attic space! The heat from the conditioned space transfers to the attic where it then transfers to the snow and melts it. The water runs down the roof until it gets to the colder roof overhang area where it re-freezes and forms icicles. Large icicles are also evidence of a more serious issue and that is ice damming. As this water runoff re-freezes at the roof overhang, it builds up and prevents water from running off the edge of the roof. This water now backs up UNDER the shingles and leaks where? Yup, the water leaks in the attic and into the perimeter of the house causing expensive damage.
Obviously, the attic space needs to well insulated. You should attempt to add as much insulation as possible without affecting attic ventilation such as soffit or gable end vents. These vents are important to keep clear. There are a few products available to accomplish this task such as fiberglass, foam and cellulose. Homeowners should seal all drafts around the house as well. On place that is a common energy waster is the perimeter rim joist at the top of the foundation walls. I have found that a 2 part, closed cell foam is the best product to use here. It not only insulates at a R-7 @ 1 inch but also stops air leaks. Fiberglass insulation is a poor choice for leak sealing.
Westbay Building Inspections can perform thermal imaging on your building to see where your insulation dollars will be best spent. Contact Bob anytime to set up an appointment.