Our family room was at one time an attached garage. We would like to update the heating in this 20x20 room. It has two forced air registers along the wall closest to the house and two baseboard heaters on two outside walls. We want to replace these raising the floor 6 or 8 inches, and using forced air under the floor to heat the room (ceiling height approx. 13 ft). How should we go about this job after we strip down everything to the cement slab? We would like to apply carpet over the sub-floor.
Answer:
You have the right idea but when you raise the floor, you might consider blocking up the joists sporadically with short lengths of 2X4. This will also make it easier to shim the whole floor into level but at the same time, it provides free airflow throughout the area and if you replace the two baseboard electrical resistance heaters with two 5" ducts, you'll get better heat. When you're installing the new ducts, pant leg a couple of 4" outlets to provide heat to the cavity under the floor. This will help make the whole floor the same temperature.
