Pricing a plaster and lath job depends on the quality of work desired. A first class project will have variations in the wall level of less than 1/16" in 10 feet. An ordinary plaster job (or commercial grade) may have waves of 1/8" to 3/16" in 10 feet. Overall, labor for first class work is approximately 20% higher than ordinary or commercial grade work.

Lath is estimated by the square yard. Allow a 5% waste factor when figuring the amount of lathing. Furring, channels, and accessories are measured by the linear foot. An extra foot should be allowed for each accessory miter or stop.

Plaster is also estimated by the square yard. Deductions for openings in plaster partitions vary by the preference and experience of the estimator, from 0% for openings of less than 2 square feet to 50% for openings greater than 2 feet in width. The estimator should allow for one extra square foot for each linear foot of horizontal interior or exterior angle located below the ceiling level. Also, double the areas of small radius work.

For curved walls with a radius less than 6' allow twice as much plaster.

Studs for Lathing and Plaster - If not specified, the studs for plaster partitions are usually spaced at no greater than 16" on center.

General Note on Finishes

Interior finish creates the identity of the building. It makes a statement about the nature of the business within—whether utilitarian, adventurous, or staid and dignified. Therefore, selection of materials should be made with an eye toward purpose and function of occupancy.

If, during the course of a project, the owner decides to cut back on costs, this is not a good area in which to do it. When a project is finished and the owner and prospective tenants walk through, they will not be able to see a complicated foundation, nor the marvelously engineered subsystems. What they will see are the finishes. If the project is “cheapened” at this point, it will show and dull the luster of an otherwise shining project.

Room Finish Schedule - A complete set of plans should contain a room finish schedule. If one is not available, it would be well worth the time and effort to put one together. A room finish schedule should contain the room number, room name (for clarity), floor materials, base materials, wainscot materials, wainscot height, wall materials (for each wall), ceiling materials, and special instructions. It is handy and easier to work out a room finish schedule on a grid system.

Surplus Finishes - Review the specifications to determine if there are any requirements to provide certain amounts of extra floor tile, ceiling pads, paint, wallcoverings, etc., for the owner’s maintenance department. In some cases, the owner may require a substantial amount of materials, especially if it is a special order or long lead time item.

Sustainability & LEED Certification - The type of materials used will have an impact on LEED certification. Current trends encourage use of natural materials, particularly those sourced locally. Materials with high recycled content are also desirable. The selection of interior finishes will also have an impact on energy conservation, light reflectance, and thermal retention.

Read more estimating tips for finishes.