The Roof Layout Plan is by far the most misunderstood part of the house plan set, at least for the average person. Builders and people familiar with home construction will know why this is. Most people will assume that a set of plans will contain all the information you will need to build a home, and most people are wrong.
If you have read our post about the Foundation Layout Plan you will remember that there are far too many factors involved in creating a foundation than can be covered in a pre-drawn set of house plans. The same is true for the roof layout, different areas of the country will have different requirements and codes for roof construction. That is why we provide a layout and not specific building or mechanical instructions. We are simply trying to communicate the functional design and conditions necessary to construct your home’s elevation in accordance with the plans
The Roof Layout sheet will have basic information for your local truss manufacturer or engineer to design your roof trusses to comply with your local codes and regulations. You will see this note on your Roof Layout Plan…”For Design Purposes Only”. This is because once your plan is given to your structural engineer and/or truss manufacturer there will need to design your actual trusses and/or framing members for your specific location. They will address issues like uplift, snow loads, live and dead loads that will be unique to each home built.
Roof Construction Issues
The roof is sometimes altered due to floor plan changes. Everything from local codes and requirements driven by the weather to community height restrictions will affect the finished roof design. There are many different ways to build a roof, so many in fact that we wrote an article on the Top 3 Types of Roof Structures. The important thing to remember about the Roof Framing Layout is that it is a tool intended for your builder and/or truss manufacturer to use when designing your roof structure.
Next up in our explanation of a plan set, we will be taking a look at the Exterior Elevation sheet.