What is typically required for support at the inside corner of a T-shaped stairwell opening?

In a T-shaped stairwell opening, the inside corner requires additional support due to the concentration of loads and the structural configuration. A header beam or double joist system is essential in these situations because it effectively distributes the weight and provides stability around the opening. This support is critical to prevent sagging, cracking, or failure of the structure at the junction of the stairwell and the surrounding floor joists.

The use of a header beam or double joists at this corner compensates for the missing joists at the opening, thus ensuring continuity and integrity in the support system. They form a robust frame that can handle the various dynamic loads that might be encountered, such as the weight of stair foot traffic and furnishings.

In contrast, alternatives like a single joist would lack the necessary strength in a high-stress area, while cantilevered beams are not suitable in this case as they serve different structural functions. Steel framing, while strong, is typically used in different applications or in specific scenarios that require steel due to load or span considerations. The combination of a header beam or a double joist system is the most effective and standard method for ensuring adequate support in the situation described.