Hennepin County Medical Center

Hennepin County Medical Center (HCMC) is a Level I trauma hospital in Minneapolis, MN, the county seat of Hennepin County. The 422-bed facility is located on five city blocks adjacent to the Metrodome. The extensive transplant specialists, stroke experts, advanced endoscopy, and trauma surgery expertise attract patients from a wide area. HCMC has been listed among America’s Best Hospitals by US News and World Report every year since 1999.

Hospitals cannot close for renovation efforts. As such, renovation projects within HCMC, or any healthcare facility, must consider a number of issues including indoor air quality. Consultants from HPS Schönox worked together with St. Paul Linoleum (the flooring contractor for the project), River City Underlayments, and HiLine Unique Flooring (the subfloor product distributor) to develop a renovation plan that would address the subfloor issues while remaining cognizant of the special factors affecting healthcare spaces.

Existing Substrate

The renovation project encompassed a large area with a variety of subfloor challenges including existing floor tile and residual adhesive. Plywood subfloors at various levels and conditions were throughout the space. A number of substrate areas were brittle or cracked.


Seams and open spaces surrounding the renovation areas are taped to prevent subfloor materials from flowing into unwanted areas. All areas of the renovation space are thoroughly vacuumed with a commercial unit. Removing all dust and debris from the subfloor enhances the bond of the materials to be used later in the project.
Measurements of the renovation space were taken and reference made to the hpsubfloors.com website to determine the required product quantities. Once the product arrived on the job site, it was pre staged throughout the facility.

Priming Using Schönox VD

Priming reduces absorption by the substrate, protects sensitive subfloors, binds residual dust, and improves adhesion of the leveling compound. An undiluted 2.6 gallon container of Schönox VD covers 1300 square feet and dries within 10 to 30 minutes. Always refer to product data sheets for complete information.

Leveling Using Schönox AP

Special dust-reduced properties within Schönox AP, synthetic gypsum self-leveling compound, allow the product to be mix ed inside of the healthcare facility with a minimal amount of dust. Schönox AP is used to level the entire renovation area. Synthetic gypsum is made from the by-product of the process used to purify emissions from power plants making the use of AP a strong environmental choice that contributes to LEED credits.
AP is ideal for renovation projects, installable to a depth of up to 2”. The final surface of the product is extremely smooth. Free of chromates and VOCs, AP sets up at 5800 psi.
Given the considerable size of this project, a pumping system was used to flow product throughout the renovation area. The smooth flow characteristics of Schönox AP make it an ideal product for use with pumping systems. Installation of the AP product using a pumping operation allows installers to efficiently mix product in one location while others distribute the product throughout the area.

Rennovated Subfloor

Schönox AP dries to a smooth, white finish ready for flooring installation in roughly 16 hours when poured at a 1/8” depth. The surface is smooth, strong, and even facilitating an efficient floor covering installation to come.