Rafter and roof joist spacing is only one part of a complex roof design that works together to form a structure that meets building codes and can hold up the weight of the roof and roof load.
Garage roof joist spacing.
Floor beam span tables of residential structural design we will now look at roof rafter and beam design.
This is the distance between joist centres.
Let s consider a basic gable wood roof framing design.
The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.
Ceiling joists of the first floor of a two story structure often serve as floor joists for the second floor.
Here we have a wood framed gable roof.
The full version allows any size.
Surveyors span tables for designing roof rafters.
Surveyors and structural engineers utilise data from tables below to help calculate the correct size strength and centres of roof timbers for the required spans and loadings.
Builders aren t bound by standard rafter spacing measurements.
This demo version is fixed at 1m clear span.
If this is the case with your structure use the floor joist table to determine maximum joist length load.
Flat roof joist calculator.
Interior spaces that exceed standard sizes such as family rooms and garages require different dimensions in the size of the joist the joist spacing and the joist span.
Usually 400 450 or 600mm but any value can be used up to 610mm max.
Continuing on from part 3.
But they do tend to space rafters in one of several industry standard increments typically.
For pitched roofs flat roofs and ceiling joists.