Von Salmi’s educational presentation “Shades of Gray in Older Homes” discusses considerations when renovating an older home.
100 years ago, homes were heated with wood or coal fireplaces and there was little to no insulation. Very few homes had electricity. There was NO indoor plumbing and most basements were stone and had dirt floors. Lifestyles were different too. There were no indoor appliances such as clothes dryers and washing machines. People bathed less often as well.
The absences of wall and ceiling insulation allowed air to migrate throughout the home and effectively exhaust internal moisture. There was no vapor barrier used or even considered. As indoor plumbing became the norm and interior moisture levels increased, the homes still breathed quite well.
In the 1970’s energy costs began to rise disproportionately and people began to insulate their homes improperly to save on heating bills. Unfortunately, the result was that homes could no longer “breathe” due to the lack of understanding ‘building science’ which was in its infancy– the fish you cooked on Friday could still be smelled a week later! In addition, the increase in appliances and occupants in the home continued to add to the accumulation of interior moisture and limited air exchange issues.
These grand old homes couldn’t hold paint any longer due to the reduced air exchanges that removed moisture, so they were being covered with improperly installed vinyl siding. The resulting trapped moisture led to big problems in older homes.
These are some of the most important issues to address when renovating older homes.
- The majority of heat loss occurs through the horizontal plane of the upper ceilings.
- Natural convection can move moisture upward through the ceiling into the attic area where, it can be removed relatively easily through proper roof design.
- ‘Cold Roof Theory’ versus ‘Hot Roof Theory’
- Caulking doors, windows, sills, exterior trims, etc. can reduce air movement to create ‘dead air’ without inhibiting the removal of moisture from the building envelope. Remember, insulation is nothing more than dead air space!
- Adding mechanical solutions such as HRV’s (Heat Recovery Ventilators) and ERV’s (Energy Recovery Ventilators) appropriate for colder climates can remove moist stale air and achieve the kinds of air exchanges required while providing reasonable energy savings that we desire for a healthy home and a happy homeowner.
The next time you visit a home built prior to the 1940’s consider looking a little deeper than just remodeling the kitchen, bathroom or any other project that the novice homeowner may have in mind. Have a discussion about the nature of the age and construction of the home and how you might be able to provide much better value to your customer by looking at the home as a system that has outlived many previous homeowners and how to maximize the proposed work to provide a greater return in terms of sustainability to the owner.