When homeowners across the Denver metro area think about Colorado weather, they usually picture crisp mountain air, endless blue skies, and famously dry winters. But anyone who has managed a home in Arvada, Golden, or Parker through late spring rainstorms or summer monsoon season knows that humidity can spike quickly especially in garden-level basements, laundry rooms, and lower levels.
If you have checked your hygrometer or smart thermostat recently and noticed the reading creeping upward, you might wonder: Is 70% humidity too high for your house, specifically, LVP?
The short answer is yes.
A 70% relative humidity reading is too high for luxury vinyl plank installations, and it poses real risks to your home's indoor environment.
While luxury vinyl planks are celebrated for being waterproof, the air and subfloor surrounding them are not immune to excessive moisture. Let’s discuss.
Table of Contents
The Core Question: Is 70% Humidity in a House Too High?
If LVP Is Waterproof, Why Does 70% Humidity Matter?
The Subfloor Swells Beneath the Planks
Moisture Trapped Under Concrete Slabs
Perimeter Tenting and Buckling
Manufacturer Warranty Requirements
Common Culprits of 70% Humidity in Front Range Homes
How to Bring 70% Humidity Down to Safe Levels
Flooring Advice Built on Education, Not Guesswork
The Core Question: Is 70% Humidity in a House Too High?
Before looking at your flooring planks specifically, let’s address the overall health of your living space. Is 70% humidity in a house too high?
According to building science standards and the EPA, ideal indoor relative humidity should sit consistently between 30% and 50%, with 60% being the absolute upper threshold.
When your indoor air climbs to 70%, several problems begin to develop:
Mold and Mildew Growth: Mold spores thrive once indoor humidity passes the 60% mark. At 70%, organic materials like drywall paper, subfloor wood, and baseboards become prime breeding grounds.
Musty Odors: Heavy, damp air traps household odors, creating that telltale basement smell.
Dust Mite Proliferation: High moisture levels cause indoor allergen counts to surge.
HVAC Strain: Air conditioners have to work twice as hard to cool humid air, running up utility bills.
So whether you are protecting your family's health or your interior finishes, 70% humidity is definitely a warning sign that needs attention.
If LVP Is Waterproof, Why Does 70% Humidity Matter?
It is one of the most common questions we hear during our shop-at-home consultations: "If luxury vinyl plank is waterproof, why should I care about high indoor humidity?"
It is true that luxury vinyl planks, especially rigid core stone-plastic composite (SPC) or wood-plastic composite (WPC) options, will not absorb water or swell the way traditional hardwood or laminate can. However, a floor installation is an entire ecosystem made up of the subfloor, the adhesive or click-lock joints, the underlayment, the perimeter expansion gaps, and the ambient air.
Here is what actually happens beneath the surface when indoor humidity sits at 70%:
The Subfloor Swells Beneath the Planks
Most main and upper-level floors in Centennial, Wheat Ridge, and Aurora sit on plywood or oriented strand board (OSB) subflooring.
Unlike LVP, wood subflooring is porous. At 70% humidity, wood absorbs moisture from the air, expanding and swelling along the edges.
When the subfloor pushes upward, it puts uneven vertical pressure on your floating vinyl planks, which can lead to creaking, joint strain, or visible ridges underfoot.
Moisture Trapped Under Concrete Slabs
If your LVP is installed in a basement over a concrete slab, high relative humidity often signals high moisture vapor emission coming through the concrete itself.
When moisture rises and hits the impermeable vinyl plank, it has nowhere to escape. Without an adequate vapor barrier, that trapped moisture can lead to mold, mildew, and foul odors beneath the floor.
Perimeter Tenting and Buckling
Even though rigid core LVP is far more stable than natural wood, extreme humidity combined with seasonal temperature changes can cause subtle dimensional expansion.
Floating floors need room to breathe. If the perimeter expansion gaps along your drywall or baseboards are too tight, the expanding floor has nowhere to go but up a problem known as "tenting" or buckling at the seams.
Manufacturer Warranty Requirements
Almost every major flooring manufacturer explicitly states acceptable relative humidity ranges in their installation guidelines typically between 35% and 55% (or occasionally 30% to 60%).
Allowing a home to stay at 70% relative humidity can void the product warranty if moisture-related buckling or subfloor failure occurs.
Common Culprits of 70% Humidity in Front Range Homes
While Colorado is known for low outdoor humidity, specific indoor scenarios often push local homes past safe levels:
Basement Slabs After Spring Runoff: In areas like Golden and Wheat Ridge with high water tables or clay-heavy soils, melting snowpack and heavy spring rain saturate the ground, pushing moisture vapor through foundation walls and basement slabs.
Oversized Air Conditioning Systems: An oversized A/C unit cools a home too rapidly, shutting off before it has completed a full dehumidification cycle and leaving cold, clammy air behind.
Whole-Home Humidifiers Left on Winter Settings: Many Denver homes rely on furnace humidifiers to fight winter dryness. If the humidistat isn't adjusted downward or turned off when warm weather arrives, indoor humidity can skyrocket.
Inadequate Ventilation: Tight modern building envelopes without proper exhaust fans in bathrooms, laundry spaces, and kitchens trap daily shower steam and cooking vapor inside.
How to Bring 70% Humidity Down to Safe Levels
Bringing your indoor humidity back into the safe 35%–50% zone is straightforward with a few practical adjustments:
Install a Dedicated Dehumidifier: For walkout basements and garden levels in Parker or Centennial, a standalone, properly sized dehumidifier running on continuous drain makes an immediate difference.
Adjust Your HVAC Settings: Keep your thermostat fan set to "AUTO" rather than "ON." When the fan runs continuously, it blows water droplets from the A/C evaporator coil right back into your living areas before they can drain away.
Turn Off Winter Humidifiers: Set your furnace humidistat to off during late spring and summer months.
Use Exhaust Fans Diligently: Run bathroom vent fans during showers and for at least 20 minutes afterward, and always use the kitchen range hood when boiling liquids.
Verify Subfloor Moisture Before Installation: If you are preparing for a new flooring project, ensure your installer performs calcium chloride or in-situ relative humidity testing on concrete slabs to verify moisture emissions before laying down planks.
Flooring Advice Built on Education, Not Guesswork
Your home is your sanctuary, and choosing the right flooring shouldn't come with hidden worries about subfloors, humidity, or tricky warranties.
At Simply Floors, we believe the best flooring decisions happen when you have honest guidance and zero pressure.
As a local, woman-owned, family-operated business founded by Buddy and Karyn Mitchell, we skip the confusion and high markups of warehouse-style retail stores. Instead, we bring our curated mobile showroom directly to your living room in Wheat Ridge, Centennial, Denver, Arvada, Aurora, Golden, and Parker.
We take the time to evaluate your subfloor, check your home's layout, and help you select quality luxury vinyl, hardwood, or carpet that matches your family’s everyday routine and local climate. Our team delivers excellence in every detail—from the initial in-home consultation to clean, professional installation backed by genuine accountability.
Arvada, CO
Address: 5945 Ward Rd Arvada, CO 80004
Phone: (303) 731-5380
Centennial, CO
Address: 8101 S Quebec St. #2 Centennial, CO 80112
Phone: (303) 731-5380
Aurora, CO
Address: 17034 E Quincy Ave. Aurora, CO 80015
Phone: (303) 731-5380
About Simply Floors Inc.
At Simply Floors, we believe the best place to choose your new flooring isn’t under the buzzing fluorescent lights of a warehouse, but in the natural light of your own home where your life actually happens. As a woman-owned, family-operated business serving the Colorado Front Range—from Arvada and Wheat Ridge to Centennial and Parker—we’ve traded the high overhead of "mega-showrooms" for a personalized shop-at-home experience that puts you in control.
Our mission is built on a simple promise to enthusiastically exceed your expectations by providing curated, high-quality selections and transparent pricing without the big-box stress. Whether you are replacing well-worn carpet or updating your forever home, our dedicated team handles every detail with "Excellence in the Ordinary," ensuring a seamless, professional journey from the first measurement to the final plank.
