Why Brand-New and Renovated Florida Homes Get Mold
Mold is usually thought of as an old-house problem: aging roofs, tired plumbing, decades of humidity. So it surprises people when it turns up in a home completed last year or a kitchen remodeled last month. In Florida it is not unusual. Mold needs moisture, a food source and time, and a construction site supplies the first two in abundance.
Moisture gets built in
A house under construction spends weeks open to the weather. During the rainy season, afternoon storms soak framing lumber, roof sheathing and subfloors before the building is closed in. If insulation and drywall go up before those materials have dried, the moisture is sealed inside the wall.
Other sources add to it:
- Concrete. A new slab and block walls hold a large amount of water and release it slowly over months. Flooring installed too soon traps it underneath.
- Wet trades. Stucco, drywall compound, paint and tile setting materials all release water as they cure.
- Stored materials. Drywall or cabinetry delivered early and left in a humid garage or uncovered on site can be damp, or already spotted, before installation.
No air conditioning during the build
In South Florida the AC is what keeps indoor humidity in check. A home under construction often goes without it for long stretches, then sits closed up and unoccupied between completion and move-in. Warm, still, humid air and fresh paper-faced drywall are an ideal combination for growth. Running the system during the dusty phase without proper filtration creates a different problem: construction dust coats the coil and ducts, giving mold something to feed on from the first day.
Tighter homes dry more slowly
Modern homes are built to be energy efficient and well sealed, with impact windows and heavy insulation. That is good for your power bill, but it also means that moisture that gets in has fewer ways to get out. Equipment sizing matters here too. An oversized air conditioner cools the home quickly and shuts off before it has run long enough to remove moisture, leaving the air cool but clammy.
Small installation defects
New does not mean flawless. The problems that most often show up in the first year or two include:
- Window and door flashing that lets wind-driven rain into the wall
- Hairline stucco cracks and unsealed penetrations for pipes and wiring
- Plumbing fittings that weep slowly inside a wall or under a cabinet
- Shower pans and tile assemblies that were not properly waterproofed
- AC drain lines without enough slope, or ducts that sweat in the attic
- Bathroom or dryer exhaust that vents into the attic instead of outdoors
Renovations carry their own risks
Remodeling an existing home introduces a few specific hazards:
- Uncovering old mold. Demolition often reveals growth behind cabinets, tile or paneling. Tearing it out without containment spreads spores through the house.
- Closing up too soon. New drywall or flooring installed over materials that are still damp from a plumbing change or a tile job.
- Covering instead of correcting. New finishes installed over a stain whose cause was never fixed.
- Changing how the house breathes. New windows or added insulation without adjusting ventilation and dehumidification.
If mold appears during demolition, stop work in that area and have it properly addressed before the project continues. It is far cheaper to deal with it while the walls are open.
Checklist for a new or newly renovated home
- Walk through after a heavy rain and check around windows, sliding doors and ceilings for dampness.
- Open every sink cabinet and look for drips, stains or swollen panels.
- Look inside the air handler closet and confirm the drain line is flowing.
- Check the filter. Replace it after any construction activity.
- Place a hygrometer in the home. Relative humidity should sit roughly between 30 and 50 percent, and below 60.
- Smell closets and rooms that have been closed. A musty odor in a new home is not normal.
- Look at baseboards and the lower edges of walls for swelling or discoloration.
- If the home will sit vacant before you move in, leave the AC running at a moderate setting.
If you find a problem
Document it with dated photos and report it in writing to the builder or contractor. What is covered, and for how long, depends on your contract and warranty documents, so review them and consult an attorney if there is a dispute. If you need the extent of the problem formally documented, an independent licensed mold assessor provides that; in Florida the assessor and the remediator on a property must be separate companies.
Closing thought
A new home deserves the same attention to moisture as an old one, particularly in its first year. Catching dampness early usually means a small repair rather than a large one. If mold has already taken hold in building materials, you can request an on-site remediation estimate at drymiami.com or call (954) 778-7999. The visit is $79, credited in full toward the job if you hire DryMiami.
Mold problem at home?
We come out, find the moisture source and give you a written remediation estimate. The visit is $79, credited in full toward your job if you hire us.
