Core Cuts: The Process in Six Steps

November 3, 2015

A core cut is taken for a variety of reasons (click here for a list), and is a crucial step in collecting data for an impending roofing project. The project, its scope, and the plan for its execution are greatly influenced by the data collected in a core cut. Here’s what to expect when a roofing contractor takes core cuts on your roof.

Step 1
The first step is to get the existing roofing surface down to a clean substrate. If it’s single-ply, you’ll use a cleaner. If it’s built-up roofing, you take a spud bar or chisel and hammer and remove embedded pea gravel from the top layer of asphalt in the roof. It needs to be smooth and free of debris.

Step 2
Next, a cut will be made through the roof assembly using a combination of razor blade, chisel, hammer, insulation saw, or a tool designed for coring the roof.

Step 3
The core cut is complete when all of the roof assembly components have been removed down to the roof deck.

Step 4
It is important that the location of the core cuts be identified on a roof plan, so if required, you can reference where the core was that is the subject of the discussion at a later date (e.g. because moisture or asbestos is present).

Step 5
Now, the types and characteristics of the materials in the roof assembly are identified, documented, and photographed. For example, notes would indicate expanded polystyrene insulation and its condition as saturated.

Step 6
Materials are either put back in place or put in a sealed plastic bag for additional analysis. Additional roof insulation can be used in place of the materials that were removed. Lastly, the core is repaired by replacing or repairing the top-level waterproofing substrate by using manufacturer’s patches, new like material, or three-course repairs, so that it is a watertight surface again.