Mold Problems Are Becoming a Costly Warning for Homeowners and Builders
Lance Luke
9/4/20265 min read
Mold in homes is becoming more than a maintenance problem. It is becoming a major construction, health, financial, and legal issue.
A recent Wall Street Journal report highlighted a growing number of homeowners who are blaming builders for mold problems they believe were caused by construction defects. Builders, on the other hand, argue that many of these claims are exaggerated, difficult to prove, or sometimes related to how a home has been maintained.
From a building expert’s standpoint, there is an important lesson here for everyone involved:
When moisture is not properly controlled, small construction mistakes can turn into very expensive problems.
Today’s Homes Have Less Margin for Error
Homes today are designed to be more energy efficient.
They are tighter, better insulated, and designed to reduce unwanted air leakage. That helps with comfort and energy costs, but it also changes how a building handles moisture.
A tightly constructed home does not dry out as easily when moisture gets where it should not be.
That means builders have to pay even closer attention to proper window installation, roofing, flashing, attic ventilation, HVAC design, drainage, and other systems that control water and humidity.
The Wall Street Journal reported that homeowners involved in mold disputes have alleged problems such as incorrectly installed windows, poorly ventilated attics, and improperly sized HVAC systems.
Those may sound like individual construction issues, but they can all have one thing in common:
moisture.
Mold May Be the Symptom, Not the Original Problem
When mold appears, many people immediately focus on removing it.
But I would want to know why it grew.
Was water entering around a window?
Was the roof allowing moisture into the building?
Was indoor humidity too high?
Was an HVAC system failing to properly control moisture?
Was an attic poorly ventilated?
Mold needs the right conditions to grow. If you remove the visible mold without correcting the moisture problem behind it, there is a good chance the problem will return.
That is why a proper investigation should look beyond what is visible.
The Disputes Can Become Very Expensive
The financial consequences can be enormous.
The Wall Street Journal reported that major home builders are facing significant litigation involving allegations of moisture intrusion and mold.
D.R. Horton is involved in litigation concerning thousands of homeowners in Louisiana who allege construction practices allowed moisture into their homes. The company’s reserves for legal claims increased from the end of fiscal 2022 through fiscal 2025.
Lennar is also facing litigation in Florida involving allegations that hundreds of homes had construction defects, including improperly installed roofs and mold inside walls.
The builders have disputed these types of claims and have argued in some cases that warranties or homeowner maintenance issues may limit their responsibility.
What this shows is that mold is not simply an issue between a homeowner and a remediation company anymore.
It can become a major construction-defect dispute involving homeowners, builders, attorneys, engineers, consultants, mold assessors, insurance companies, and other experts.
Mold Testing Can Produce Very Different Answers
Another problem is that mold testing is not always as straightforward as homeowners may expect.
Air samples can measure mold spores, but results can vary depending on where samples are collected, when they are collected, environmental conditions, and the testing methods used.
There is also no universally accepted number of airborne mold spores that automatically determines whether a home is unsafe.
That can create dramatically different conclusions.
The Wall Street Journal described one homeowner whose mold consultant reported concentrations as high as approximately 2.2 million spores per cubic meter. A mold assessor hired by the builder had tested the property only days earlier and reportedly found levels around 500 spores per cubic meter.
Those are remarkably different results from the same home.
This is exactly why mold cases should not be decided by one number alone.
Testing needs to be considered together with the physical condition of the building.
Follow the Building Evidence
When investigating a moisture or mold problem, I believe the building itself needs to be examined carefully.
Look at the windows.
Look at the roof.
Look behind walls where appropriate.
Check moisture levels.
Evaluate ventilation.
Review the HVAC system.
Look for staining, condensation, water intrusion, deteriorated materials, and other evidence.
And document everything.
A mold test may tell you that mold spores were detected, but it may not tell you how moisture entered the building or who is responsible for it.
That requires investigation.
Homeowners Can Face Serious Financial Losses
One homeowner discussed in the Wall Street Journal report illustrates just how costly these disputes can become.
She purchased her home in 2022 and later reported significant humidity problems, including sweating walls and fogging windows, along with health symptoms. She eventually sued the builder.
According to the report, she expects to spend about $75,000 on experts by the time the case is completed.
Her property was recently assessed at approximately $117,000, compared with an earlier value of $318,700.
Mold disclosure requirements can also make selling an affected property much more difficult.
That is a tremendous financial consequence from a problem that may have begun with moisture getting into or remaining inside a building.
Health Claims Require Care
There is evidence that damp and moldy environments can aggravate asthma and other respiratory problems.
At the same time, there are many other health conditions being attributed to mold without the same level of scientific support.
That is where everyone needs to stay within their area of expertise.
A building expert can investigate the physical building conditions.
A mold specialist can evaluate mold.
A qualified medical professional should evaluate health concerns.
Trying to make conclusions outside those areas can create confusion, especially when a case ends up in litigation.
Builders Need to Pay Attention to the Details
There is another important message in all of this.
As homes become tighter and more energy efficient, construction quality becomes even more important.
Energy efficiency itself is not the problem.
The problem occurs when a tightly constructed building has a defect that allows moisture inside or prevents moisture from escaping.
A poorly installed window may be much less forgiving.
An HVAC mistake may create greater humidity problems.
Poor attic ventilation may allow moisture to remain where it should not.
The building industry has to recognize that moisture management is becoming increasingly important as construction methods and energy requirements change.
The Bottom Line
The growing number of mold disputes should be a warning to homeowners and builders alike.
For homeowners, do not ignore recurring condensation, musty smells, water stains, fogging windows, damp walls, or other signs of excessive moisture.
For builders, do not underestimate the importance of proper installation, waterproofing, ventilation, and moisture control.
And when mold is discovered, do not stop at the mold.
Find out why it is there.
Mold may be what you can see, but the real problem may be hidden behind the wall, above the ceiling, around a window, inside the HVAC system, or somewhere else in the building.
Finding and correcting that underlying problem is the key to protecting the building, the homeowner, and potentially the builder from a much larger problem later.
Lance Luke
National Building Expert
Building Consultant & Construction Expert
Phone: (808) 422-2132
Email: lanceluke@hawaiibuildingexpert.com
Website: hawaiibuildingexpert.com
Reach out anytime, we’re here to help.
Phone
(808) 422-2132
© 2026. All rights reserved.
Contact
newsletter