In which orientation should tongue and groove siding be installed?

Tongue and groove siding should be installed with the tongue facing up. This orientation is important for proper water drainage. When the siding is installed tongue up, any water that collects on the surface is directed away from the underlying structure, helping to prevent moisture buildup that could lead to rot or mold. This design takes advantage of gravity, allowing water to drip off the edges rather than seep into the joints between the boards.

Using this orientation also ensures that any gaps created during installation will serve to shed water rather than collect it, providing additional protection for the building's framing and exterior. Proper installation not only maintains the aesthetic appeal of the siding but also enhances its durability and longevity.

The other options do not adhere to best practices for moisture management, which can compromise the effectiveness of the siding and lead to structural issues over time.