When our home was built in 1989, the builder placed insulation in the garage ceiling, saying it would help if we ever converted the attic to a bedroom.
A few years ago we had the attic finished, but the room seems to be cool and the floors are even colder. Do you have any ideas why and what we can do to change it?
The room above the garage as well as the walls and ceilings of the rest of the home are most likely insulated to the minimum allowed by code at that time. Over the years, as energy costs have increased, the standards for insulating and air sealing a home have changed and are now a priority for both builders and buyers.
In the early 1970s and ’80s, energy conservation was low on builders’ priority lists, and air sealing was most likely never considered.
It should be performed after the home is framed and insulated and then inspected by a third party before hanging the drywall. Products that are used to stop airflow include cardboard, drywall, house wrap and expanding foam insulation.
I think that the insulation in your garage ceiling was installed before it was covered with drywall. The installers simply stapled the insulation to the bottom of the ceiling joists, leaving a large air gap between the top of the insulation and the bottom of the attic’s flooring. Airflow from the soffits to the attic now enters each gap and cools or warms the bedroom’s floors.
If accessible, the gaps at the ends of the garage’s ceiling joists can be blocked with additional insulation and cardboard or any type of air barrier.
A preferred improvement would be to fill the gap above the insulation with loose fill, blown-in insulation by either drilling through the bedroom floors or running a long blower hose in between each joist and filling the gap as the hose is slowly removed.
Another possible factor: A heat register may have been added to the room from the existing ductwork. The ductwork is designed for the cubic feet of the existing living area. By adding a heat register, the furnace blower may not be able to move enough air for the additional room.
Have the furnace inspected further by a qualified HVAC (heating venting air conditioning) technician.