Gypsum Underlayment in the Twin Cities — USG Levelrock® Certified Installer
Gypsum underlayment is not a commodity pour — it is a fire-rated, sound-attenuating, code-compliant substrate system that determines whether a multifamily building passes inspection, whether hotel guests hear the room above them, and whether a senior living facility meets the acoustic standards its residents deserve. ATR Floors is a USG Levelrock® certified installer with 30 years of gypsum underlayment experience across hundreds of Twin Cities multifamily, hospitality, and senior living projects.
USG Levelrock®
Certified Installer
15K–25K
Sq Ft Pumped Per Day
UL-Listed
Fire-Rated Assemblies
Where Gypsum Underlayment Is Used
Gypsum underlayment is the standard substrate for multistory commercial construction where fire rating, sound control, and a smooth finished surface are all required by code or by spec.
Multifamily Housing
Apartments, condominiums, student housing, and senior living. Every floor in a mid-rise or high-rise wood-frame or steel-frame building typically receives gypsum underlayment over the structural subfloor for fire resistance and STC/IIC separation.
Hospitality
Guest room floors demand acoustical isolation from adjacent rooms and the floor above. Gypsum underlayment creates the mass layer in the floor/ceiling assembly that absorbs both impact sound and airborne sound.
Senior Living & Assisted Living
Memory care, independent living, and skilled nursing facilities. Residents are particularly sensitive to noise transfer between units and between common areas and residential corridors.
Mixed-Use Buildings
Commercial-over-residential, retail-over-office, and other mixed-occupancy structures where the IBC requires fire-rated floor/ceiling assemblies between occupancy types.
Radiant Heating Encapsulation
USG Levelrock 3500 FL is formulated for radiant heating. Pumped directly over PEX tubing, it fills voids and creates a continuous thermal mass layer that distributes heat evenly and protects the tubing from point loads.
UL-Listed Fire-Rated Assemblies
IBC requires fire-rated assemblies between dwelling units (typically 1-hour minimum). USG Levelrock systems are components of dozens of UL-listed assemblies — we install to the exact UL specification your project requires.
The Levelrock Product Line
ATR Floors is one of a limited number of contractors in the Twin Cities metro authorized to install the full Levelrock product line. We specify the right product for your assembly — not the cheapest one on the truck.
Why Choose ATR for Gypsum Underlayment
USG Levelrock® Certified
Factory-trained on USG products, equipment, and installation procedures.
UL Fire Rating Compliance
Installed to the exact UL-listed assembly specification — product, thickness, and method.
STC/IIC Performance
Properly designed assemblies regularly achieve STC and IIC ratings in the mid-60s to low 70s.
Pump-Truck Production
15,000 to 25,000 sq ft per day per pump crew on an open floor plate. A 200-unit mid-rise in days, not weeks.
Industries We Serve With Gypsum
Frequently Asked Questions
Standard pour depth ranges from 3/4 inch to 1-1/2 inches for most multifamily and hospitality applications. Deeper pours up to 3 inches are possible for specific UL assemblies, radiant heating encapsulation, or severe substrate leveling. The required depth is determined by the UL assembly designation and acoustical performance targets.
Standard cure time is 14 to 28 days for most USG Levelrock products under normal ambient conditions. USG Levelrock RH is formulated for faster moisture dissipation. Regardless of calendar days, we test moisture per ASTM F2170 before any floor covering is installed.
Gypsum underlayment alone does not have an STC or IIC rating — the rating belongs to the complete floor/ceiling assembly. A 1-1/2 inch gypsum pour as part of a properly designed assembly typically contributes to tested ratings in the STC 55 to 65 and IIC 55 to 65 range. Premium assemblies can exceed 70.
Yes. USG Levelrock 3500 FL is specifically designed for radiant heating encapsulation. The gypsum is pumped over the pressurized tubing, fills around each tube, and creates a continuous thermal mass layer. We coordinate with your mechanical contractor to maintain pressure during the pour.
Yes. ATR Floors is a USG Levelrock certified installer serving the Twin Cities metro. Certification means our crews are factory-trained on USG Levelrock products, equipment, and installation procedures. We install to USG's published specifications and maintain the quality standards required to preserve the product warranty and the UL assembly listing.
Spec the Underlayment. Then Spec the Installer.
Include the UL assembly designation, sq ft, number of floors, and project schedule. We respond within one business day with a detailed scope and pump-staging plan.