Several factors affect the cost of lightning protection. Primarily, these factors are: size and complexity of the roof,
and the type and depth of the soil.Soil: After lightning strikes a properly placed lightning rod, the potentially explosive energy must be safely channeled into the earth. To accomplish this, several paths with multiple connections to the surrounding soil need to be provided. Soils found in the Northeast are often of a very high resistivity‚ which is the reason New England receives the most severe thunderstorms, and high resistivity creates the most challenging conditions for achieving an effective ground. The basic code requirement for ten foot ground rods is impossible in granite, and of little value in coarse sand or gravel. Therefore, homes with foundations in blasted bedrock that have extensive landscaping are the most expensive to ground, and homes with deep loam/clay type soils are the easiest and least expensive to ground.
Roof: A flat roof or ranch style home with a shallow pitch and asphalt shingles are easy to work on. A steep roof with metal or slate requires additional care and time. Steeples, gable dormers, cupolas, and tall chimneys can increase costs.
Cost: For a rough idea of cost to protect a typical home, figure two dollars per square foot of living space.
Estimates: Ideally, a proposal is based on drawings sent by mail for an upcoming project. For existing buildings, a sketch showing a plan view of the roof with a few dimensions given, along with soil conditions and a couple of photos is often enough to determine the exact cost.
Site Visits / Problem Solving: For a large residential complex, commercial, or municipal site that is experiencing lightning-related problems, a site visit can be conducted. Site visits involve several hours of inspection and research, a written summary of conditions found, and recommendations for action to be taken, along with estimated costs. Formal site visits may include testing of existing grounds and/or soil resistance tests. Cost is usually between $600. and $1,600.
Inspections: The condition of existing lightning rod systems often necessitates replacement rather than repair. Many older systems do not meet current codes, and since there is little policing of the lightning protection industry, many systems have been poorly installed. Making repairs creates liability issues, implied warranties, and other lose/lose situations involving lawyers. Informal inspections for homes are available, with ground testing, at a cost between $75. and $300.