Home Improvement--General/basement wall moisture

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QUESTION: Hello Mr. Burford,
I was wondering if you could shed some light on an issue that has affected the sale of my home.

I have a 41-year-old bungalo that was recently inspected by a local home inspector and found to have a 19% basement wall humidity level. Now, I live in Canada and  this Winter saw record snowfall accumulations that only recently began to thaw out. (To give you an idea of the amount of snow involved, it had piled up to approximately 4 ft in front of the home after clearing of the driveway.

My questions to you are as follows: Is this value of wall humidity actually not a positive finding given the amount of water that had settled into the soil surrounding the foundation? (There were no visible leaks on the floors.) Can a single measurement, or series of measurements, taken at such a time of year really be indicative of a problem? What value of moisture level would be acceptable and how should this level be properly determined?

Thank you for any help that you might be able to offer.

ANSWER: Gus,

Please clarify the reference to Canada and the snow fall. Is that the bungalow you are selling? When you say basement you do mean a below ground level wall don't you? Was the wall masonry or wood? Is the basement a conditioned space? Is there a complaint? Was the inspector hired by the buyer? Do you know what test equipment was used to get a 19% reading?

Generally:
-Moisture content can vary based on time of year and weather conditions. Humidity is not water.
-Molds typically need 60% (plus) humidity to grow.
-Wood framing lumber when delivered to a lumber yard is supposed to be kiln dried down to 19% moisture content.
-Basements are damp because they are below ground. The lower temperature of air can cause condensation of moisture during summer and moisture in the wall probably does exist in a house 41 years old. I am not sure current wall drainage systems even existed 41 years ago.


---------- FOLLOW-UP ----------

QUESTION: Hello again Sir,

"Please clarify the reference to Canada and the snow fall."

(Yes the home is in Canada (Southern Ontario) and the snow fall described was in the area where the home is situated.)

Is that the bungalow you are selling?

(Yes. I am referring to the home up for sale.)

When you say basement you do mean a below ground level wall don't you?
(Yes. Exactly.)

Was the wall masonry or wood?
(The wall is masonry. Some places are uncovered by wood paneling over wall stud lumber and I assume that this is where the readings were taken.)

Is the basement a conditioned space?
(The basement is finished/habitable, i.e. flooring, ceiling, wood paneling installed over wall studs. There are a few areas where access to the primary masonry wall is available.)

Is there a complaint?
(The buyer's backed out of a sale contract based, primarily, on this "problem")

Was the inspector hired by the buyer?
(Yes.)

Do you know what test equipment was used to get a 19% reading?
(No. Nor do I know how the equipment was used, i.e. was the 19% an average value of several measurements along the one wall affected or a single high level value.)

I hope these clarifications help.
Thank you again for your help!
Sincerely, Gus

Answer
Gus,

You need to talk to the seller about the exact nature of their concerns and find out exactly how and what the moisture measurement was.
There may be some misapprehension of the inspector's report.

One point to clarify is what is meant by wall humidity. Humidity is typically a measurement of water vapor in air not a material like a wall.

They may be using their inspector's report as an excuse to get out of their contract. Which means you are holding earnest money they want back and which is your leverage to get clarification.  

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Thomas Buford

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Licensed Architect in Virginia since 1984.
New Homes, Additions, Alterations, Outbuildings, Failure Forensics;
Small Construction Projects; Remediation and Repair

www.tbbuford.com

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Architectural design, planning, construction and repair.
Schematic Design
objectives statement
space planning
feasibility study
structural, mechanical, plumbing
and electrical system integration
Permit Drawings
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Contract Documents
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pre-qualification of bidders
bidding
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pay request certification
Construction failure diagnostics
water intrusion
structural failures, ...

Due to life safety concerns regarding some aspects of construction I may not be able to help with all questions.
I do not answer structural specification questions without a site visit.

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Arlington Journal

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5 year Bachelor of Architecture from
Virginia Polytechnic Institute and State University (VPI-SU)

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