Minimum Roof Height For Dormer

You need to have a roof pitch that gives you at least the height of a window and then some.

Minimum roof height for dormer.

To assess whether you have the space to accommodate this measure the clear headroom of your existing space from the top of the joists to the bottom of the rafters. A dormer window therefore is only used with steeper pitches that have a useable interior space in the ceiling area. Most codes require that at least one half of the ceiling in a room be 80 inches or higher and that the ceiling over the other half have a minimum height of usually 48 or 60 inches. The ideal scenario is if you can stand upright in the centre of your loft and raise your arm above your head without crunching your hand on the inside of the roof.

You need to consider the slope requirements of each panel to determine this minimum slope. This translates into a fall of just under 2 5 on an 8 foot roof. There are minimum practical requirements for headroom which the designs for your loft conversion must be able to meet. I always recommend at least a minimum pitch of 1 in 40.

There is no fabrication of roof trusses required. Express the slope of a metal roof by a ratio which indicates the pitch of the roof. A shallow pitch cannot sustain a dormer window simply because the interior space makes a dormer window impossible. Fix your roof deck and you are done.

The minimum slope of a roof depends on the roof s profile. A third consideration that will effect the size and shape of the dormer is the minimum ceiling height.