Sagging Ridge Line On Roof

Check the ceiling for sagging by attaching a string on one end of the beam and run it along the bottom edge of the beam.

Sagging ridge line on roof.

The base of the triangle forms the ceiling or roof joints while the rafters are the diagonal walls that slant toward the ridge line. Ridge beam or ridge board sagging or damaged roofs may sag because a ridge beam or ridge board is cracked or damaged. A sagging roof line may original from the ceiling s horizontal rafters. So you should start by inspecting the roof from the under side or attic.

The first step is to the basement first. The most common cause of sag at the roof ridge is loss of triangulation due to failure of the bottom leg of the triangle which makes the peak of the roof sag and top of the walls spread outward in the area of failure. Sagging ridge originally we were going to replace the ridge and fix the blown out walls customer finally realized it wasn t going to happen his way he is a retired engineer so we ripped off the roof and started over. When the roof joints and rafters are improperly constructed this can lead to a sagging roof later on.

There weren t any particular indications of this occurring. Typically they are lapped and then toe nailed together in its center so that the correct length can be achieved. When the roof framing is assembled two ceiling rafters are often joined together to create a longer span. If the line does not continually follow the bottom of the beam and the bottom of the beam is below the line the beam is sagging.

And then there is the puzzle of the vaulted ceiling. As the roof ridge sagged downwards red line and arrow the centers of the front and rear walls of this little house bulged outwards telegraphing that movement into the outwards lean of the front porch as the front walls of the home also pushed the porch roof outwards blue line and arrow. Sagging roof lines can originate with the horizontal ceiling rafters. Think of your roof as a triangle.

This may have been caused by any number of factors.