Step 1: Prep the Area

After removing any old carpet (Image 1) and tackless strips to prepare the work area, prepare to cut the new opening by marking a chalk line to maintain a perfect square (Image 2).

Choose a location that is convenient for upstairs and downstairs and clear of any door openings. Check the local building codes for additional guidelines.

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    Image 1

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    Image 2

Step 2: Begin Cutting the Hole and Add 2x4 Supports

With the chalk line in place, start cutting the hole with a circular saw.

It's a good idea to switch to a reciprocating saw once you get to the corners and when it's time to cut the joists.

Before cutting the joists, add 2x4s for temporary support. These boards will be removed after the floors have been reinforced.

Step 3: Reinforce the Floor

To reinforce the floor, add double joists using 2x8s that run the width of the room. Secure them with a framing nailer (Image 1).

Finally, add joist hangers for additional support (Image 2).

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    Image 1

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    Image 2