Section r305 1 1 indicates the minimum ceiling height for basements without habitable spaces and hallways.
Minimum legal height attic.
To meet the minimum of 30 psf live load 2 x 6 joists that are spaced every 16 inches can span up to about 10 feet or a bit more depending on the joist material different woods have different strengths.
If staircases are less than one meter wide they should have a handrail on at least one side.
In an attic room with a sloping ceiling or projection below ceiling line or non habitable room or similar a height that does not unduly interfere with the proper functioning of the room or space.
The access opening should be located in a hallway or other readily accessible location and minimum 22 x 30.
Portions of a room with a sloping ceiling measuring less than 5 feet 1524 mm or a furred ceiling measuring less than 7 feet 2134 mm from the finished floor to the finished ceiling shall not be considered as contributing to the minimum required habitable area for that room.
The height of handrails should be between 900mm and 100mm.
In a stairway 2 0m measured vertically above the nosing line.
Areas with ceilings lower than 5 feet are allowed but do not count toward the official room area total irc.
In other words if your attic has 200 square feet over which the ceiling is at least 5 feet high then for a minimum of 100 square feet 50 of 200 that is the ceiling height needs to be at.
If the attic space is smaller than these specs then an access hatch is not required.
One way is by working within the home s existing footprint and converting the attic into living space.
2 x 10 joists spaced every 16 inches can span 13 to 14 feet.
It s obviously ideal to have even more but that is the bare minimum from a regulatory standpoint.
Room area is this case is calculated as the total floor space with walls at least 5 feet tall.
So what is the minimum height needed.
Staircases more than one meter must have handrails on both sides.
Joist sizing is based primarily on the span distance between supports and the joist spacing.
More than 50 of the ceiling space should be on average a minimum height.
Minimum ceiling height for basements with no habitable spaces section r305 1 1.
Basements without habitable spaces and hallways shall have a minimum ceiling height of no less than 6 feet 8 inches.
R304 4 height effect on room area.
Minimum vertical height of 30 inches measured from the top of the ceiling framing members to the bottom of the roof framing members.
