All radii of the same circle are equal in length. By definition, a radius is one-half of the diameter. The diameter is a chord
through the center of the circle. Contractors are often required to calculate more complex, irregular shapes such as polygons,
hexagons, octagons, etc. It is best to divide the area into more common shapes and add or subtract the pieces to arrive at the total.

Standpipes are pipes or tanks on roofs of buildings, which store a supply of water and provide an extra supply when normal water pressures fall.

Mechanical and electrical drawings must be reviewed for pipe trenching or conduits that are in the basement or under slab-ongrade. This work is often overlooked since it is not shown in civil drawings. Most site work is shown on the civil drawings, which the contractor uses to determine the cut and fill quantities to bring the site to the new grade.

When drywall is taken-off by the whole system, all components are included and quantified as SF. When individual drywall components are taken off, drywall is taken-off by the SF of surface area to be covered, with quantities separated according to the type and thickness, and may be extended to the number of specific size sheets required. Multiple layers of fire-rated assemblies should be listed in the take-off according to their position in the assembly. Taping, finishing, joint compound and texturing are taken-off by the SF of coverage. Reinforcing tape and trim are taken-off by LF.

The Pythagorean Theorem, and Right Triangle Law, or 3-4-5 Triangle Rule, allows framers and contractors to square up work
in the field. Basically, the sum of the squares of two sides (A(2) + B(2)) is equal to the square of the hypotenuse (C(2)). Contractors doing roofing, rafter or truss work, or measuring and cutting stringers or winders for stairways readily use this formula.

Framing plans are modified structural drawings. For residential construction, plan, elevation, section, and detail drawings show most wood framing and finish carpentry work.

It is important to use correct units of measure when calculating area and volume. Feet multiplied by feet equals square feet.
Yards multiplied by yards equals square yards. Feet multiplied by feet, multiplied by feet equals cubic feet. Yards multiplied
by yards, multiplied by yards equals cubic yards. Multiplying a
dimension in feet by a dimension in inches is erroneous and one of the dimensions must be converted before the calculation
can be correctly made. Example: Calculate the area of a space 12'-6" x 2O'-4": 12'-6" = 12.50'; 2O'-3" = 23.33'; 12.50' x 23.33'
= 291.63sq. ft.

Main lines are heavy, unbroken lines that show the main outlines of the wall, floor, elevation, detail, or section. Hidden or invisible
lines are light, dashed lines that indicate the outlines of an object hidden or obstructed from immediate view.

A standard interior door is 6'-8" high, 2'-0" to 3'-0" wide and typically 1-3/8" thick, with 1-3/4" thick, softwood frames.

Setting materials, thin-set or adhesive, are calculated by the SF of the tile to be set and converted to sales units based on the manufacturer's recommended coverage for the particular product. The manufacturer specifies the ratio of liquid to dry material for bonding additives. Tile joint grout is calculated the same as setting materials.

When pouring concrete in cold weather, it is important to keep the concrete above freezing for the first few days, and is usually covered with plastic to contain heat and moisture from the mixture in order to encourage curing.

Horizontal bars are taken-off by total length multiplied by the number of bars shown. Vertical bars are taken-off by dividing the
total length of wall or footing by the spacing, and multiplying by their height or length.

The species and grade of wood and type of application must be considered during estimation of wood siding. The final quantity of siding materials must include deductions for all openings greater than 4 SF, such as doors and windows. The species and grade of wood and type of application must be considered
during estimation of wood siding. The final quantity of siding materials must include deductions for all openings greater than 4 SF, such as doors and windows. The species and grade of wood
and type of application must be considered during estimation of wood siding. The final quantity of siding materials must include deductions for all openings greater than 4 SF, such as doors and windows.

Plastic pipe support is very important but receives little attention with adverse results. Support spacing depends upon pipe size, operating temp, wall thickness and mechanical properties of the specific pipe material. Specific support spacings are available from the pipe manufacturers.

Various types of risk and allocation of responsibility are contained in contract clauses. An exculpatory clause should be inserted as well, intended to shift the responsibility, for example, from the designer's errors and omissions to the contractor. Allocations of risk denote who is lawfully responsible and liable for violations under the law in connection to the work. Responsibilities are  the contractor's, however some may be shared with the owner, such as acts of God and weather extremes, etc.

By including dimensions, the contractor can construct a simple single sketch drawing with instructions for workers to use.
The intent is to show shapes, locations, and dimensions of construction details.

Water stain is the most penetrating of all stains, especially when used on base wood. Water-soluble powder is made from aniline dyes. Best results are obtained when the powder is added to very warm water and dissolved completely. Spirit stains are also aniline dyes, but are mixed with alcohol and are difficult to use since they dry quickly and possibly unevenly. Pigment oil stains are powders and are soluble in naphtha or turpentine. Pigments are made from various oxides and silicates mixtures.

Excavation is taken off as the calculation of length, width and depth of area to be excavated in CF, and converted to CY, where 1 CY = 27CF.

It is often necessary to show location dimensions of several construction features in a straight line. The total chain of
dimensions should equal the overall total dimension if one is given.