Midrafter Roof Deflection

Collar ties collar ties are connections between opposing rafters at the upper one third of the roof frame area just below the ridge and they are required at a 48 4 maximum spacing which is every other rafter of a 24 on center spacing and every third rafter with 16 on center spacing.

Midrafter roof deflection.

What you see is the result of weight and time and gravity. Collar ties rafter ties tension beams structural ridge beams. Load limits on the roof of a building. The builder was made aware of this issue and had the roofer who framed the house and installed.

We moved into the house march 2013. I ve never considered combined deflection. Deflection for exterior walls with interior gypsum board finish shall be limited to allowable deflection of h 180. Note it gives the allowable deflection based on a fractional span quantity so a larger denominator will yield less deflection.

Some of these can support the roof and prevent ridge sagging and wall spreading. Roofs are under a lot of pressure. Strucalc will automatically load the correct duration. Refer to section r703 7 2 reason.

Duration factor the duration factor reflects the ability of wood to support larger loads for shorter periods of time as well as smaller loads for longer periods of time. The current combined row for floors and ceilings with plaster and stucco. This article describes and illustrates the different types of support that prevents roof sagging and wall bulging at buildings including definitions of collar ties rafter ties and structural ridge beams. The shingles or sheathing on the homes roof is lifting deflecting causing ripples in the roof.

If the rafter deflects 2 and purlin 1 5 does necessarily mean it is 3 5 deflection. See the table below. When i design roof if it is flatter than 3 12 slope i do l 480 deflection. Such a roof looks a little bit like the saddle on a horse.

This was noticed for the first time a couple of months after the singles were installed. In order to stay intact and in place a roof must be able to resist loads both permanent and temporary that are pushing. This is intended to be an editorial clean up and not change any current requirements for deflection criteria. Roof rafters typical total load deflection criterion is the length of the rafter divided by 180 and is given in inches.

My tennessee home was started in may 2012 and the roof was put on in late june. You have probably seen this and it is most likely due to roof deflection sag and creep. The center beam is probably not terribly thick. Chapter 3 of the international residential code irc provides the maximum allowable deflection for a given structural member floor roof wall etc.

Roof beam double span. This roof is composed of rafters which meet a center ridge beam. That is just my preference. Default deflection criteria for the following members.

Roof purlin single span.