The design process starts at the roof and continues down to the foundation.
Roof beam design.
A roof is an integral part of a building and people try to personalise the roof designs to achieve optimum architectural splendour.
The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.
Ridge beams are required by code if the roof slope is less than 3 in 12 irc section r802 3.
Design of rectangular reinforced concrete beam procedure.
Ridge beam sizing is based on the span of the beam between supports and the amount of roof load supported by the beam.
The loads on the ridge beam are carried by vertical posts at the beam ends down through the building structural walls to the building foundation.
For a porch roof the beam needs to be sized according to the maximum snow loads in your area and you must know enough about the porch design to determine how the load will be distributed and over what distance the beam will carry the load.
Here we have a wood framed gable roof.
Use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads.
The process involves one simple equation and some knowledge of the loads that the beam will carry.
This calculator matches up with 90 of the applications in the 2012 international residential code book.
Most interior beams need to include the roof load.
Continuing on from part 3.
The colour and material of the roof complement the structural integrity of a building.
If there is are any questions about anything else then you should contact your supplier or an engineer.
Open source wood find tools designing with roof rafter span tables long span 35 lvl beam design roofdek manual structural roof deckingtimber steel framing manual single span ridge beamglulam ridge beam span.
Floor beam span tables of residential structural design we will now look at roof rafter and beam design.
There are two approaches for the design of beams.
It has been my experience to never use a beam smaller than a two ply 2 x 8.
A ridge board is a non structural member that serves as a prop for opposing rafters to rest against and connect to.
The design of concrete beam includes the estimation of cross section dimension and reinforcement area to resist applied loads.
You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths.
The structural design for gravity loads involves evaluating each member for performance under the anticipated live loads dead loads and a combined force of live load plus dead load often called the total load or tl.
Firstly begin the design by selecting depth and width of the beam then compute reinforcement area.
