NORWAY — Prepare to be rattled.

McGoldrick Brothers Blasting Services 0f Windham will begin blasting a large ledge on the Orchard Street side of the new $1.8 million medical building that is being built on the former downtown Cummings Mill site.

The blasting may start as soon as Wednesday and will continue for three or four days, probably one blast per day, said Mason Rowell of Landry/French Construction of Scarborough, general contractor for the project.

Ledge is being removed at the base of the hill that extends up to Orchard Street, but the slope will remain and eventually will be landscaped, Rowell said.

The site is within 500 feet of the Norway Downtown Historic District and its century-old buildings, some of which are fragile. The blasting company has documented as many of the buildings’ interiors and exteriors as possible for insurance purposes.

Shawn McGoldrick of McGoldrick Brothers Blasting Services said Friday that building owners and others should not be concerned when the blasting begins.

“It’s not like we’re going to ride in on horseback and throw a stick of dynamite,” he said.

The site will be secured. Then people who happen to be in the area at the time of the blast will hear three horn signals. That signifies there is five minutes until the blast. Two horns will then be sounded to indicate one minute until blast and then one horn will signal “all clear.”

McGoldrick described the blast impact as feeling like a heavy truck is rumbling by, but the blast will not be significantly loud. Rubber tire mats will be placed over the load holes to secure the debris from flying.

“It will be a normal construction blast,” McGoldrick said.

As a prelude to the blasting, inspectors from BECC Co. have been in town notifying downtown building owners and documenting the state of the buildings for insurance purposes. Most of the buildings are in the Norway Downtown National Historic District and are more than 100 years old.

Taylor LaPierre of BECC, an independent geotechnical company based in Yarmouth, said the company is only documenting buildings within 500 feet of the blast site.

A videographer and two other inspectors have gone into as many buildings as possible, spending as much as 90 minutes videotaping everything from the building foundation to the windows.

The documentation includes areas such as the unrestored second-floor stage area of the Norway Opera House.

The pre-blast survey records any visible defects within or outside the structure before the blast.

According to information from the company, small air pulses from the blasting operations can cause loose windows and loose doors to rattle loud enough to be heard by someone standing nearby. The ground vibration will also be heard or felt at times near the area.

The effects are monitored and recorded and kept “well below” the safe guidelines recommended by the federal government for occupied residences, according to BECC.

Town Manager David Holt said he was not made aware of the upcoming blasting but he believes today’s blasting methods are a lot safer than many envision.

The town does not require local permitting for the blasting, LaPierre said.

Construction on the building is expected to begin in late May or early June.

The 25,000-square-foot medical office complex is being built on an 8-acre lot purchased by Western Maine Health about seven years ago. The site is the former C.B. Cummings & Sons wood mill on Pikes Hill Road

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