HVAC question: Ductwork in Attic

[Clarence Martinn]

Here is the problem:

2 Story house. Separate Apartments , with each having their own utilities. Lower Apartment, has Gas Boiler heat system. That works great.

The Upper Apartment, on the other hand, has a forced hot air Gas fired Furnace in a furnace room that is just off the Master Bedroom up there. In fact, if you were in the master Bedroom, and looked at the door that leads to the Furnace, you would have thought it was just a Closet. Now, the Ductwork for the Gas Furnace is ALL in the Attic. Heat vents are all on the upper parts of the walls near the ceilings. Got to find some way to eliminate that heating system, so that it does not heat up the flat roof , and cause Ice and water damage. The ductwork is just a few inches from the flat roof edge in the Attic. No amount of insulation or wrapping can prevent the attic from heating up , causing the Ice and Snow problems.

What are my options?

I was thinking of just shutting that furnace off, and installing a direct vent , through the wall Gas Furnace in the Living Room upstairs. That would heat the Living Rm , Dining Room , Kitchen and possibly the Hallway leading to the 2 Bedrooms and the Bathroom. That still leaves the question on how to heat the 2 Bedrooms and the Bathroom.

How would I run the Gas lines for those heaters? Through the walls? As it is now, the Gas line for the Furnace runs up from the Basement , inside the walls and then comes out of the wall in the Furnace room.

[Robert Maloney]

Is there any way to spray foam the underside of the roof with closed cell foam? That would turn the attic into a conditioned space, thus eliminating snow and ice problems. Probably would be cheaper than installing a new furnace, and continue to save you money over the years.

[Jim Becker]

Is there any way to spray foam the underside of the roof with closed cell foam? That would turn the attic into a conditioned space, thus eliminating snow and ice problems. Probably would be cheaper than installing a new furnace, and continue to save you money over the years.
I agree with this approach and it's how things were done in our addition. The closed cell spray foam envelope makes the attic space conditioned space and the HVAC system up there doesn't have to work very hard at all...and there are zero roof issues in cold weather.

[Lee Schierer]

Ice dams are caused by heat build up in your attic as you surmised. You need to let that heat out of the attic and prevent additional heat from getting in. Increase the insulation on the duct work and ceiling and add roof vents and ventilated soffits to let the outside air flow through your attic. An air tight insulated door door should replace the current door to your attic which is probably letting warm air rise into the attic.

[Jerome Stanek]

Or you could use a split system

[James Pallas]

Many flat roof houses in the southwest use a furr down in the hallway to run ductwork. It makes for a 7' ceiling in the hall. It does get the ductwork into conditioned space.
Jim