I recently had a house built, when the inspector checked the house he said the house had extreme moisture in the walls from 15 to 18%. My husband and I are considering pulling out of the deal. What would you do in this situation, and what are normal moisture level for a new house. Is there any way this can be fix? Please help
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We would need a lot more information to form a reasoned opinion.
Where is the house located? What kind of construction is it? Where did he take the moisture readings? What kind of materials did he (?) test? What kind of moisture meter? (Probe or radio wave?)
How much experience does the HI have? How long has he had that toy?*
Were the moisture readings the same in all locations of thew house?
Some general observations:
I have never inspected a home where all of the moisture readings were within such a narrow range: mainly for the simple reason that different materials give different readings at the same moisture levels.
Even different species of wood will give different readings. Temperature can affect the reading.
When I inspect a home and am looking for moisture issues, what I am looking for are _differences_ in readings - it would be next to impossible to recalibrate for each reading and material during a home inspection; but if I find that say, a piece of trim along the side of an interior door is reading 10%, and the same type of wood trim is reading 20% along the baseboard on an outside basement wall, or under a window, I know there is a moisture concern.
As a very general impression, subject to more facts (e.g., are you in a desert of a sub-tropical rain forest?) I would not consider readings of 15% to 18% to be "extreme" in new construction.
As a very general rule, mildew doesn't start growing until moisture levels are 20%, and in my experience, that level has to be maintained for a long period of time. (In theory, mildew and mold can start to grow after about 48 hours; in reality, it usually takes a lot longer than that.)
Also, new construction usually gives higher moisture readings at first because of water in the various building materials: concrete, drywall tape, wood framing, paint, etc. It takes a while for a house to "dry out"
But your location and the other stuff will affect how those figures should be evaluated.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
*In my experience, many inexperienced home inspectors get caught up in "readings" and don't always understand what they are reading or what those readings mean. For example, an HI I know, who shall go unnamed, got himself a combustible gas sniffer. $300 bucks or so. "Oh boy!"
In one of the first houses he did after getting it, he tested the gas lines for leaks, sniffing at each connection. He found gas leaks at each one! "Run for your lives!"
Boy, was I, er, "he" embarrassed when "he" found out that pipe dope gives false positives on the brand of combustible gas meter "he" had!
God never gives us small ideas.
Sojourners: Christians for Justice and Peace
Hey Bob, when you say mildew starts to grow at 20% moisture level, does this mean that the humidity in my house is greater than 20% (is this relative humidity?), then I will have a mildew problem?
I don't mean to thread-jack the discussion, but I live in a house which in the summer feels like a rainforest, even with a dehumidifier going. Thanks.
6
That 20% figure is based on the Building Science website (at least from a couple of years ago - or maybe it was the Massachusetts Wood Technology site)
Relative humidity of the air does not directly translate into moisture content in wood and other materials.
I don't have exact figures, but in NW Ohio (which is pretty similar in my experience to other, non-coastal cites in the NE and "north eastern" Midwest - and is fairly humid) in the summer, I expect to find wood moisture levels at around 12-14 percent in attic rafter framing, and 12-16% in "reasonably dry" crawl spaces.
Those figures go down a few points in winter, but from house to house they vary more depending on inside humidity levels.
>>I live in a house which in the summer feels like a rainforest, even with a dehumidifier going. Thanks.
What part of the country are you in? Do you use a central air conditioner? Is the A/C unit sized properly? (too big an A/C unit doesn't dehumidify sufficiently, and can make the house feel cold and clammy.)
What is the capacity of the dehumidifier?God never gives us small ideas.
Sojourners: Christians for Justice and Peace
I've sent you an email, so this thread can focus on its originator's question. Thanks!
You should not have a mildew or mold problem as long as you maintain the relative humidity below 60% - above that number you will start to experience problems
That is not completely true.
Even with RH much less than 60% you can get condensation in the walls that can lead to mold.
And of course any kind of water leaks.
Just keeping the RH below 60% is no guarantee that you won't have a mold problem.
My apologies - you are correct.
My point was that even without leaks or condensation formation, a relative humidity in excess of 60% can stimulate mildew or mold growth.
FWIW, I generally recommend to my clients not setting humidi-stat levels much above 40%, and keeping an eye open for condensation in cool/cold areas.
God never gives us small ideas.
Sojourners: Christians for Justice and Peace
Yep, 40% is pretty much the limit for any area which experiences winter, and you have to turn it down from there as the temp falls. Condensation on the windows in the morning should normally be the guide -- a little mist in the corners (when temp is below about 10F) means humidity's about right, more means it's too wet, less means it's drier than it needs to be.I got a humidifier with an outside temp sensor a couple of years back. That works real nice in terms of matching the humidity to the outside temp. The one thing it lacks is a 25-hour memory so that humidity doesn't go up too much during the day.
>>Condensation on the windows in the morning should normally be the guide --I tell my clients to use a highly scientific approach for adjusting their humidistats: if there's condensation, turn it down; if they're shooting sparks when they touch the door knobs, jack it up a bit....God never gives us small ideas.
Sojourners: Christians for Justice and Peace
Edited 10/20/2004 7:04 pm ET by Bob Walker
What type / kind of walls and how soon after completetion...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
what part of the country do you live in...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming
WOW!!! What a Ride!
The 2000 IRC One and Two Family Dwelling Code allows up to 19% moisture in the framing lumber when delivered to the site. After about a year this moisture content will drop to around 8 or 9%. Some shrinkage usually occurs and some cracks may be noted in the drywall.
Really need more information as to what your inspector was finding and where. Why was he looking at the moisure content in the first place? Was there a stain indicating a possible roof leak or other water intrusion?