Roof Without Rafter Ties

If you are framing a cathedral ceiling there are a couple ways to deal with the need for rafter ties.

Roof without rafter ties.

The shape and size of a roof depends on the span and the floor plan of the building. You can possibly remove them altogether of you include posts in the gable walls to support a structural ridge. Tie a new gable or hip roof to an existing gable or hip roof with valley rafters which perform the same function as ledgers. And the roof covering material determines the size cross section area of the roofing timbers used.

The roof framing mock up below shows a standard rafter tie. A rafter tie is a tension tie in the lower third of opposing gable rafters that is intended to resist the outward thrust of the rafter under a load. Without the proper support of rafter ties or a structural ridge a typical gable or sloped roof will sag downwards while pushing the building walls outwards towards a catastrophe. In many situations you ll find that ceiling joists installed parallel to the rafters are intended to function as rafter ties.

Like rafter ties collar ties are horizontal members that tie the rafters. Rafter ties or ceiling joists acting as rafter ties are required by code unless the house is designed so that the walls or a structural ridge beam carries the full load of the roof. Strip the roofing from the old roof at the connection point to. We include sketches of collar ties rafter ties and structural ridge beams as well as illustrations of collapsing and collapsed structures where these roof rafter.

From a practical perspective it s difficult to use high rafter ties on a low pitched roof because the force in each tie increases with the inverse of the pitch. Collar ties collar ties are an alternative to rafter ties in framing where a conventional ceiling is not desirable.