Know What You Want Before You Start

With any building project, you must decide exactly what you want to do before you can prepare an accurate estimate of the cost.

1. Consider the nature of the project and how it will affect the design and the materials you select. How much wear and tear will the finished product undergo?

Is it to be permanent or just temporary? Will it be visible or hidden, utilitarian or decorative? Should it match or coordinate with existing materials? Is it going to be indoors or outdoors? Will it be used by children or a disabled person?

2. Consider what characteristics it must have--size, shape, accesses, light, sound properties, storage, special fixtures, appliances and other similar factors.

3. Consider your budget. Do you have to keep costs within a certain amount?

With these factors in mind, sketch rough plans for the project. Even if you intend to hire an architect, the drawing process gives you a better understanding of what’s involved.

Supplies

Once you have drawn up plans, make lists of the materials you’ll need. Do them in the order of actual construction to reduce the chances of omitting anything. It also makes clearer at which points you’ll require the aid of workers and subcontractors.

List every item, including hardware, fasteners, caulk and abrasives. Also list any tools you may have to buy or rent.

Choose the type and quality of materials you want to use, and, if applicable, pick the finish (paint, stain or natural) you want them to have.

You may be required to adhere to local building codes for the entire project and, possibly, in selecting materials and hardware. Contact your local planning or building department for a copy of the zoning regulations.

Quantities

After you have decided on the types of materials, figure out the quantities. Some materials are sold and estimated in several ways. To find out how a material is sold, call and ask the supplier.

For materials that are installed in a straight line, such as pipes or wall molding, simply measure the length needed in feet. For materials that frame or border, you’ll need to find the perimeter of the area to be enclosed. And for many other materials, you’ll need to calculate either the area to be covered or the volume to be filled.

Here are some basic formulas for estimating:

* The perimeter (distance around the edges) of a rectangle or other straight-sided shape is found by adding the lengths of all its sides.

* To find the area of a rectangle, multiply its length by its width.

* The area of a triangle is determined by multiplying half the length of its base by its height.

* To find the area of a circle, multiply the circle’s radius (half the diameter or distance across the circle) times itself, then multiply the result by 3.1416 (“pi”).

* To calculate the circumference of (distance around) a circle, multiply its diameter by 3.1416.

* To determine the volume of a cube or other box-like space, multiply the length of the base by the width of the base, then multiply the result by the height.

* Sketch complex shapes on graph paper, letting each square on the paper equal 1 square foot or 1 square inch. Then add up whole squares and those more than one-third filled.

After making estimates, add a fudge factor (say, 20%) to cover waste, errors, damage, miscalculations and future repairs.

Costs

To decide if you can afford the project, determine an approximate overall cost by multiplying the number of units you’ve calculated by each material by the price per unit. Total all the results.

To confirm your estimate, submit your materials list to several local suppliers for price quotes, then add the cost of labor and subcontractors.