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Preparing for Concrete Cutting When Installing New Windows or Doors

Home improvement projects often involve replacing older windows or doors with larger, more energy efficient models. However, this can present challenges when the new frames no longer fit through the existing concrete foundation openings. Proper planning is key to a smooth concrete cutting process.



Measuring and Marking Cut Lines

The first step is to accurately measure the new window and door sizes, including rough openings needed for flashing/sealant. Use a laser level and tape measure to mark cut lines on the concrete at least 1.5-2 inches beyond the planned framing.


For extra precision, print full-size templates of the new units to hold against the foundation while marking. Make relief cuts at all four corners before starting the perimeter cuts.


Choosing the Right Equipment

For straight cuts along marked lines, a gas-powered walk-behind concrete saw is the best option. These saws can cut to variable depths in a single pass.


In tight corners where saws can't reach, use an electric concrete chipping hammer to break concrete away in small pieces. Always wear proper safety gear like a respirator, gloves and goggles for this dusty work.


For larger jobs, consider renting a truck-mounted concrete wall saw which offers more cutting power and capacity for deep cuts. Make relief cuts every 2-3 feet when using these heavy-duty saws.


Removing Cut Sections

Once the perimeter and relief cuts are complete, carefully break away and remove the cut concrete sections. A gas-powered concrete breaker makes quick work of this.



Wear proper protective equipment and work slowly to avoid creating excessive dust or damaging surrounding areas. Transport debris immediately rather than letting it accumulate.


Inspect the base material and re-compact if needed before setting the new window/door frames. Thoroughly clean the opening and apply foundation flashing or a waterproof coating to protect exposed edges.


Finishing Details

After installing the new frames, backfill the perimeter with pea gravel for drainage then apply a foundation coating or flashing tape. This helps prevent water intrusion behind the units.


Seal any small cracks that appear with a flexible concrete crack sealant. These projects often settle slightly as the new framing takes load, so flexible sealants hold up better than rigid ones over time.


With thorough preparation and the right tools, concrete cutting for window and door replacements goes smoothly. Don't hesitate to contact us for help planning and completing your next project.

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