No floor covering is better than the subfloor over which it is installed. The finished appearance and performance of the floor covering will be determined and affected, in part, by the condition of the subfloor. It is essential that all subfloors be structurally sound, finished smooth, flat, level, permanently dry, clean and free of all foreign materials such as dust, paint, grease, oils, solvents, curing and hardening compounds, sealers, asphalt and old adhesive residue. Subfloor preparation should be done with the permanent HVAC set at a minimum of 68o F (20o C).

Vacuuming the subfloor with a commercial shop vac is a preferred method of removing dirt and dust. For concrete floors, damp mopping the subfloor is an excellent way to remove fine dust. A clean subfloor ensures proper bond between the subfloor and the floor covering.

Note: Wherever trade names, trademarks, product names or company names are mentioned, they are used only as a reference to establish a comparative standard of quality. It should not be assumed that these products are the only products for the suggested or intended use. Also, it does not mean that other products of similar or equal quality may not be suitable.


GRADE LEVELS

1. On Grade - A location for a finished floor with no portion below ground level, and with the floor and the ground in contact or separated by less than 18 in. of well-ventilated space between the bottom of the lowest horizontal structural
member and the ground at any point.

2. Above Grade - A location for a finished floor where the floor is not in contact with the ground and which provides at least 18 in. of well-ventilated space between the bottom of the lowest horizontal structural member and the ground at any point.

3. Below Grade - A location for a floor structure which is in contact with the ground or with less than 18 in. of well-ventilated space between the bottom of the lowest horizontal structural member and the ground, at any point and if part or all of the floor is below ground level.


DEFINITIONS

1. Subfloor - That structural layer intended to provide support for design loadings. The substrate for the underlayment.

2. Underlayment - The layer of material installed on or over the subfloor to provide a smooth, clean surface to receive the resilient floor covering.

3. Subfloor-underlayment combination - Designed to meet the structural requirements and provide a smooth surface to receive the floor covering.

Existing floors must be structurally sound, free from excessive movement and have well-ventilated air space below. Stagestep floor coverings should not be installed over wooden subfloors built on sleepers over, on grade, or below grade concrete floors without the use of a vapor barrier*. Failure to use a vapor barrier* will result in high rates of failure due to the excessive moisture vapor emissions from the concrete.

UNDERLAYMENTS

Underlayment panels are used to correct deficiencies in the subfloor and to provide a smooth, sound surface on which to adhere the resilient flooring.

APA Underlayment Grade plywood, minimum 1/2" thickness, with fully sanded face is the preferred panel. The underlayment must be free of any foreign material that may cause staining, such as patching compounds, sealers, inks, solvents, etc.

The underlayment should be installed with dispersion type staples or screws placed every 4 to 6 in. in the field and every 2 to 3 in. along the seams. Sanding is a preferred method for smoothing joints.

Other types of underlayment panels such as Tecply, Multiply and Masonite Brand Underlayment should not be used with Stagestep systems. Always install and fasten underlayment panels according to the manufacturer's recommendations.

There are certain types of subfloors and underlayment that through years of experience are known to be prone to failure and are therefore NOT recommended.

• Particle board/chip board, tempered hardboard, or Pressure Treated woods are not suitable to install Stagestep floor coverings over.
• Lauan board of at least 1/2" thickness is considered a suitable underlayment to install Stagestep floor coverings over.

Regardless of which underlayment is used, any failures in the performance of the underlayment, or Stagestep floor coverings due to the underlayment, is the responsibility of the underlayment manufacturer and not Stagestep.

Strip Wood/Plank Flooring

Due to expansion and contraction of the boards during seasonal changes, Stagestep recommends the use of Springstep IV underlayment panels be installed over these types of floors. NOTE: The use of a skim coat of patching material over wooden subfloors may cause more problems than it resolves especially in the joint areas. The moisture from the patch is absorbed by the wood, swelling the wood fibers and causing telegraphing through the newly installed floor covering. Proper installation of a wooden subfloor is critical to the successful installation of your flooring surface. Installation of wooden subfloors should be given the same attention as far as job site conditions as when installing Stagestep floor coverings.

Concrete Floors (Refer to ASTM F710-98)

Floors shall be smooth, rigid, flat, level, permanently dry, clean and free of all foreign material such as dust, paint, grease, oils, solvents, curing and hardening compounds, sealers, bond breakers, asphalt and old adhesive residue.

Concrete shall have a minimum compressive strength of 3500 psi/150 pounds per cubic feet and be covered with a vapor barrier* prior to construction of the subfloor.

Telegraphing of patched joints and subfloor imperfections may often be accentuated if the flooring material is maintained with a high gloss finish.

Existing Resilient Floors

Most Stagestep floor covering may be installed over a single layer of non-cushioned resilient flooring provided it meets certain conditions.

• The existing flooring must be fully adhered and well-bonded.
• The existing flooring must not be embossed or textured enough that it will telegraph through the new flooring.
• All waxes and finishes must be removed and rinsed with clean water and a pH test should be conducted to assure stripper residues have been removed. An adhesive bond test should be conducted to ensure proper bond between the adhesive and the existing flooring material.
• Cuts, gouges, dents and other irregularities must be repaired or replaced.
• The current subfloor must be sprung and must meet the recommendations of the existing and the new floor covering.
• The use of embossing levelers is not recommended for commercial installations.

NOTE: Application of a skim coat of patching material over the existing resilient flooring may cause more problems than it resolves, such as bonding failures, cracking and indentations.

NOTE: The responsibility of determining if the existing flooring is suitable to be installed over rests solely with the installer and flooring contractor. If there is any doubt as to its suitability, it should be removed or an acceptable underlayment installed over it.

Installations over existing resilient flooring may be more susceptible to indentation, and there is always a possibility the existing flooring may telegraph through. Remember, you are no better than what you go over.

Radiant Heated Floors

Stagestep floor coverings may be installed over radiant heated floors provided the operating temperature does not exceed 85F. To allow proper adhesion of the adhesive to the subfloor, the radiant heating system should be lowered or turned off for at least 48 hours prior to installation of the Stagestep flooring material. This is to ensure the surface temperature of the subfloor does not exceed 65F during the installation of the flooring material. The room temperature must be maintained at a minimum of 65F prior to, during, and after installation for 72 hours after which the temperature of the radiant heating system can be increased. When raising the floor temperature, do so gradually so that the substrate and flooring material can adapt to the temperature change together. A rapid change could result in bonding problems. For more information, contact Stagestep Technical Services.

* The use of a 12mil or better vapor barrier is mandatory when installing Stagestep products over, above, on, or below grade concrete. Failure to do so will void all warranties.