Yes, it is possible to extend the two columns to the second floor while leaving the one in the middle unchanged. This can be achieved by incorporating a structural design that supports the load distribution and ensures stability for the second-floor structure.

Here's a general approach to achieve this:

1. Structural Analysis:

   • Conduct a structural analysis to determine the load-bearing capacity of the existing columns and their ability to support the additional load from the second floor.
   • Consider factors such as material strength, column spacing, column size, and foundation support.

2. Design Reinforcement:

   • Reinforce the two columns intended to extend to the second floor to accommodate the additional load.
   • This may involve increasing the size of the columns, using stronger materials, or adding additional reinforcement such as steel bars (rebars) within the columns.

3. Extension of Columns:

   • Extend the two columns from the ground floor to the second floor level.
   • This can be achieved by continuing the column structure vertically through the first-floor ceiling to the second-floor ceiling, ensuring proper alignment and stability.

4. Floor Support:

   • Ensure that the second-floor structure is adequately supported by the extended columns.
   • This may involve integrating beams or other structural elements between the extended columns to provide support for the second-floor joists or slabs.

5. Foundation Considerations:

   • Evaluate the foundation system to ensure it can adequately support the increased load from the extended columns and second-floor structure.
   • If necessary, reinforce the foundation or incorporate additional footings to distribute the load effectively.

6. Professional Consultation:

   • Engage a structural engineer or architect with expertise in building design to develop detailed plans and specifications for the column extension and second-floor support.
   • Ensure compliance with local building codes and regulations throughout the design and construction process.

By following these steps and working closely with experienced professionals, it is possible to extend the two columns to the second floor while leaving the middle column unchanged in a two-story house. This approach ensures structural integrity and safety while achieving the desired architectural design.