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RustyRealtor 12-01-2012 11:25 AM

Musty Smell In New Construction
Hello Everyone,

I tore a rotten old house down to the block and did a rebuild. The house is in Nashville, TN. It is 32' x 34' on a non vented crawl. I left the house for awhile and when I returned some months later there was a terrible musty smell in the house and my newly finished hardwood floors cupped. In the crawlspace my rim joist was wet in all four corners. The concrete block was also wet. I completely encapsulated the crawl space, including the door, with 12 mil vapor barrier from "Crawlspace Concepts". Looks great and a week later corners, rim joists and concrete block are all dry. But the smell persists and may even be worse. I read conflicting opinions about the use of a dehumidifier and would like to avoid using one if at all possible. I've also read that I need conditioned air down there, but my HVAC is in the attic and there's not a lot of room for a trunk.

Will cutting a few inconspicuous holes in the floor with vent covers help at all?

Will the smell go away eventually?

Will a deodorant or air freshener help?

What is the difference between humidity and relative humidity?

Gary in WA 12-02-2012 06:04 PM

The air currents in the closed crawl did not reach the corners = wet. As you closed it, now it requires conditioning by; I am not surprised it smells wet and musty, without forced air moving under there. I doubt a few vent holes to the conditioned areas will help much. The rim joists should have been insulated with foamboard, as the walls;


RustyRealtor 12-04-2012 11:54 PM

Thanks for the reply and the link contained therein.
I am going to install a 12" louvered exhaust fan in the crawl space door and cut four holes in the main floor, one under the electric stove, one under the washer, one under the bed in the master and one undetermined. I will run the fan three hours at a time, twelve hours a day. I'll let you know.

Why is rigid foam better than unfaced bat or rock wool? Can I drape rock wool down my encapsulated crawl space walls? Is rock wool not inorganic and therefore impervious to mold and mildew?

Windows on Wash 12-05-2012 07:22 AM

Rigid foam will have a higher R-Value per inch as well as be more tolerant and resistant to any moisture.

joecaption 12-05-2012 07:52 AM

Why would you cut holes in the floor:eek:

RustyRealtor 12-05-2012 07:24 PM

I cut three holes equalling one square foot in the floor so as to draw air from the living space and into the crawl space. I did it today and it really seems to have helped. I think the odor is leaving. My duct work is all in the attic and I can't figure a way to get a duct down there. I put a 600 cfm louvered exhaust fan in the crawl space door. I put the fan on a timer running three hours on and three hours off. I turned the fan on before I cut the holes in the floor and the vinyl in the crawl lifted up and it looked like a big balloon down there. The plastic settled back down after I cut the holes. The fan is made by Dayton and the motor gets really hot. It worries me a little. I am leaving town tomorrow and i sure hope the motor doesn't fry. Cutting holes in the floor is a probably a band aid and i know it sounds crazy, but I just didn't know what else to do. I am broke and the musty odor was making me ill. It seems much better now.

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