Furnace Room Open To Crawl Space

Originally Posted By: pmizeres
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Inspected a house the other day that had a finished basement configuration with a crawl space. The furnace room was separated from the finished basement by a solid door, but the entire back half of the furnace room opened up to a 4’ high crawl space behind it, approximately 30’ wide by 20’ deep. The crawl space had no vents to the exterior and had a dirt floor. Discovered that the supply plenum that ran in the crawl space had an open duct. The floor above the crawl space was not insulated nor were the foundation walls. The furnace room consisted of a gas fired furnace and gas fired water heater. There was no evidence of rusting, poor combustion, back drafting, nor any evidence of a moisture problem in the crawl space. Did it make sense to call out the lack of foundation cross ventilation, lack of a crawl space floor moisture barrier, lack of overhead floor insuation w/ vapor barrier, and sealing off the open supply duct? What about going a step further to recommend sealing off the crawl space to the furnace room and replacing the solid door with a louvered door in conjunction with an evaluation by a licensed HVAC technician, or is this over kill? Comments appreciated.


Originally Posted By: Blaine Wiley
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My home in VA was set up the similarly. There were no problems because the crawl space which was under the family room was conditioned living space. Sounds like the crawl space in this house was also conditioned living space due to the supply duct and register, and would not require any outside venting, floor insulation, etc. I did install a moisture barrier on the floor in my house, just for the heck of it.


Was there a combustion air vent for the furnace and water heater, or was there enough adequate air supply?


Originally Posted By: pmizeres
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Blain,


No combustion vent for the gas fired applilances except for the enclosed crawl space unless the occupants left the solid door open to the finished basement. This configuration just doesn't "feel" right. I was wondering if someone left the open supply vent in the crawl space on purpose, but there was no provision for a return vent.

Pete.


Originally Posted By: ekartal
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If the solid door is indeed being left open for combustion air, I would call it out because the door should be fully louvered (in case it’s closed).


Erol Kartal
ProInspect