Floor Refinishers Allston

Installing Hard Wood Floors

INSTALLATION OVER A CONCRETE SLAB
Hardwood flooring can be installed successfully over a slab, which is on-grade or above grade. Below-grade installations are not recommended. The slab must be constructed properly (flat, dry and level with a trowel finish.). The slab must be sound, level, and free of grease, oil stains and dust. Grind off any high spots and fill low spots. Prepare the slab by sweeping it clean. To be absolutely certain moisture does not reach the finished floor, a vapor barrier must be used on top of the slab. Where this is placed will depend on the type of system used.) Plywood-On-Slab System: Cover the entire slab with 4-mil or heavier polyethylene film overlapping edges 4-6″ and allowing enough to extend under the baseboard on all sides. This system uses 3/4″ or 1/2″ or thicker sheeting grade exterior plywood as the subfloor. Stagger plywood and joints every 4″ by cutting the first sheet of every other run. Loose lay plywood panels over entire floor. Leave 3/4″ space at all wall lines and 1/4″ to 1/2″ between panels. Cut plywood to fit within 1/8″ near and around door jambs and other obstructions where finish trim will not be used. Fasten the plywood with a powder-actuated concrete nailer or hammer-driven concrete nails. Be sure to flatten out the plywood and fasten securely. Starting at the center of the panel and working toward the edges, use at least nine nails per panel.) Screed Systems: This system uses flat, dry 2″x4″ screeds (sometimes called sleepers) of random lengths from 18″ to 48″, as a nailing base.

INSTALLATION OVER WOOD JOIST CONSTRUCTION
Use either exterior plywood or boards of NO.1 or NO.2 Common Pine or other softwood suitable for floors over wood joist. If plywood, use a fully 1/2″, preferably 5/8″ or thicker, performance rated. Lay panels with grain of faces at right angles to joists. Nail every 6\” along each joist. Use appropriate nails for plywood thickness. Allow 1/8\” spacing at panel ends and 1/4\” at panel edges, unless otherwise recommended by the panel manufacturer.

Laying and Fastening the Finish Floor – Strip Flooring:
The following instructions apply to strip flooring laid on plywood-on-slab, on screeds, and plywood or board sub-floors. Where a plywood or board subfloor is used, start by re-nailing any loose area and sweeping the subfloor clean. Then cover it with a good grade of 15lb. asphalt felt or building paper, lapped 4″ at the seams. This helps keep out dust, retards moisture from below, and helps prevent squeaks in dry seasons. Direction of finish flooring. For best appearance, lay the flooring in the direction of the longest dimension of the room or building. If a hallway parallels the long dimension of the room, begin the flooring by snapping a chalk line through the center of the hall and work from there into the room. Use a slip-tongue to reverse direction when you complete the hall later.

Laying a New Strip Floor Over an Old Floor:
The existing wood floor can serve as a subfloor. Drive down any raised nails, re-nail loose boards and replace any warped boards that can not be made level. Sweep and clean the floor well, but do not use water. Remove thresholds to allow the new flooring to run flush through doorways, remove doors and baseboard. Lay asphalt felt or building paper over the old floor. Always install the new floor at right angles to the old floor boards.

Parquet, Block, Herringbone and Similar Flooring:
The styles and types of block and parquet flooring as well as the recommended procedures for application vary some-what among the different manufacturers. Detailed installation instructions are usually provided with the flooring or are available from the manufacturer or distributor. There are two ways to lay out parquet. The most common is with edges of parquet units ( and thus the lines they form square with the walls of the room. The other way is a diagonal pattern, with lines at 45degrees angle to walls. For additional information, see the NOFMA Installation Manual.