I have a small (1,000 sq ft) house that was built 7 years ago in Mendocino CA , 2 miles from the ocean in a very rainy climate. The house was built on an inverted “T” foundation, with a 20″ crawlspace. The soil level is very shallow and at about a foot it becomes hardpan. The issue we are having is that the foundation seems to be trapping moisture. At the perimeter of the doors and windows, mildew has built up, both on the metal frames and on the nearby sheetrock. We installed pre-finished cherry flooring over 15 lb felt about 6 months ago and have noticed that the edges of the boards are cupping slightly (yes, the flooring was acclimitized to the room). When I opened the access hatch to the crawlspace, the air below reeked of mildew. Almost all of the gutters have been run to tightlines, but there is no French drain, nor have we put a sump pump in. The house is heated with a propane heat stove. I have several questions: Could the propane fireplace be introducing moisture into the house? Would a wood stove help dry it out? Is there some way to protect the flooring from cupping any more?
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You need to cover the ground under the house with plastic. Also add more underflooor ventilation
Tell me more about the propane heat stove? Style, vent size, BTU capacity.
Is the propane fireplace vented...if it is a non-vented unit then it is the problem and a health & safety hazard!
Do you have a good CO detector?
How do you heat your hot water? Cook your food? Propane or electric?
Gas burning appliances can be great sources for excess moisture in the envelope of a house. All ust be properly vented.
Do you have a bath vent fan? Does the vent leave the attic through the roof?
Is the clothes dryer properly vented? or does it just drop into the crawlspace? Is the dryer gas or electric?
How many plants do you have in the house? Aquariums?
How tightly built is the house? Is there make-up air provided?
Is the crawlspace soil wet/very damp?
Have you examined (crawled) the crawlspace thoroughly to see if you have a plumbing leak? Sewage or waterline?
Or a rainwater leak....or wet seep via ground water?
Sorry........just more questions!
.............................Iron Helix
Thanks so much for your detailed reply to my query re moisture in our house (4779.1). To answer your questions...
the propane fireplace is vented with a double wall flue, a don't know the brand.
we have a flash heater and a propane stove that is not vented.
yes there is a bath vent, it is used regularly, it vents thru the roof
there is no washer or dryer
there are several house plants, no aquariums
the house was built about 7 years ago, but I don't think it is a very tight house. There is no make-up air exchanger.
the crawlspace dirt is dry now in the summer, but can be soaking in the winter. There is no appearance of a water or plumbing leak in the crawlspace.
Those are all good questions to consider-- I had been focusing on the exterior sources of moisture rather than the interior ones.
We have decided to switch from a propane fireplace to a wood fireplace, as that should dry the interior considerably. One problem with this house is that it was basically built slightly below grade and there is a low deck surounding the house on two sides. Thus it is difficult to either change the grade or put a french drain in (unless I do it 6' from the foundation).We will put plastic in the crawlspace. I am planning on running it up the walls (about 24") and attaching it to the sill plate. My concern is that there is so much moisture outside that if I just put it on the soil, the water will penetrate and then sit on top of the plastic. I have also thought of putting a dehumidifier in the crawlspace.
If you have any additional thoughts/advice, I would love it.
Thanks!
Marie Jones
>>We have decided to switch from a propane fireplace to a wood fireplace, as that should dry the interior considerably.
Why do you think that?
Heat is heat: it takes cooler dry air and turns it into warmer dry air.
>>We will put plastic in the crawlspace. I am planning on running it up the walls (about 24") and attaching it to the sill plate.
Running it up the walls just traps moisture in the foundation and you can get rising damp into the walls.
>>I have also thought of putting a dehumidifier in the crawlspace.
An alternative is conditioning the crawl: line the ground with the vapor barrier, insulate the walls (depending on your climate) and blow conditioned (heated or cooled & dehumidified) into the crawl.
Consider having it checked by an experienced home inspector (say with >1,000 inspections) in your area. Home inspectors see what works and what doesn't work. Try to pick an HI who uses that as his/her benchmark - there are a lot of "rules" and ratios and rules of thumb that may or may not actually have real world effect; you want someone who puts actual performance first.
1God never gives us small ideas.
Sojourners: Christians for Justice and Peace
To ad to Bob's comments about the fireplace....wood fireplaces are nice for the soul....and bad for the wallet......because usually more heat goes up the flue than stays in the house.
I won't even address cutting, hauling, kindling, tending, and cleaning up factors associated with a wood burning fireplace....keep the propane.
What is a flash heater? Also you described your gutter downs as draining/connected to a "tighline"? Both these are not terms used where I live. Please clue me in!
From your description of the lay of the house to the lot, it may be that you are trapping rainwater or groundwater.
It may be good to look at creating a drainage moat at the crawlspace perimeter and then cutting in a drain to daylight, or using a sump pump to rid yourself of the liquid portion of any seepage onto the CS.
Follow-up with Bob's suggestion to climatize the CS with HVAC to pull out the moisture vapor.
What is the heat source on the water heater? If gas, have the vent checked.
Is the flue on the gas fireplace clear and clean? Has it been inspected lately?
What kind of siding do you have? What kind of windows?
Do your windows sweat on the interior side of the house in the winter?
How many is "several".....when frost time comes my DW moves over 60 plants indoors, some require two folks to carry...that is several....how about you!?
Can you send a picture of the house and it's setting?
Still hunting for that answer....................Iron Helix
Additionally (edit)....Does the the "B"metal flue from the fireplace propane heater run all the way from the back of the heater up through the chimney and out a metal cover and cap combo.....
Or does the fireplace masonry flue act as the conduit for the heater vent until it reaches the top of the masonry flue where the top was covered with a metal assembly that has a B-vent cap stuck in the middle of it.?
Hoe many BTU's is the fireplace heater?
Edited 10/3/2004 7:49 am ET by Iron Helix
mariejones:
Beginning with the least expensive remedy for your 'moisture' problem, I suggest installing a 6-10 mil polyethylene vapor barrier inside your crawlspace. Next; I would check to be sure the 'grade' around your foundation slopes 'away' from the house. Next; be certain that any roof gutters/downspouts carry water away from the foundation. Also, make certain there is adequate ventilation in the crawl space. You might consider a dehumidifier inside your living space, but only after the other remedies are completed. Since none of these solutions are expensive, do them all. Wolfe