Roof Rafer Construction Wall Sag

This prevents the rafter from potentially shifting causing your roof to sag or worse collapse inward.

Roof rafer construction wall sag.

Some are cut to fit the plate while in hasty construction they are merely laid on top of the plate and nailed in place. By cutting a birdsmouth notch those forces are redirected downward onto the wall plate and wall which is exactly where you want those forces to go. Rafter ties on gable type roofs are usually horizontal wood pieces often 2 4 s or 2 6 s that help keep the exterior wall tops from spreading outwardly. It is more accurate to describe such a roof as semi flat.

The angle at which the notch is cut is called the seat cut. Rafters are generally laid in series side by side providing a base to support roof decks roof coverings and so on. A rafter is a structural component that is used as part of a roof construction. Rafters are nailed to the plate not framed into it.

So in reality flat roofs are never totally flat but rather have a slight fall the minimum of a flat roof is 1 50. The overhang of the roof at the wall is called the eaves. 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. After all it s the job of the walls to hold the roof up.

The free ends of the expander are bolted below mid span on a pair of sagged opposing rafters. Angle joined together by the hypotenuse which will determine the slope of the roof. Sagging rafters can lead to serious problems with the entire roofing system. The rafter is seated upon the wall plate by means of a notch or birdsmouth joint which is cut one third into the rafter.

Going to pull the trigger on a new roof but wanted to level the structure out first. The top angle or bevel is called the plumb cut. A roof must have some slope in order to shed rainwater. They may extend a short distance beyond the wall to form the eaves and protect the sides of the building.

The expanding roof stretcher used to push out the sag in the roof frame is mounted in place between a rafter pair. Rafters rest on the top wall plate. It s 1x8 ship lap that has shrunk to the point of a gap between each board. My original intent was to chop it off and re rafter re sheet sheeting.

Normally in the bottom third area of the rafters or sitting on the exterior wall top plate. Check for damage to rafter ties as well as their connection to the exterior walls. 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 ties were lost or omitted. Typically it runs from the ridge or hip of the roof to the wall plate of the external wall.

As work progresses hanging the roof sag remover tool from one of the new collar ties already in place eases holding it in place for bolting.