Insulating Roof Trusses

Place the plastic sheeting on top of the rolled insulation.

Insulating roof trusses.

To insulate the underside of the ceiling between rafters you ll want to add insulation to the exterior portion of the finished ceiling. Ibc dictates acceptable placement and composition of roofing materials in chapter 15 but describes required thermal efficiency of the roof in chapter 13 which references the international energy conservation code iecc the minimum required thermal resistance varies. The bigger issue comes around when you are dealing with a roof that has exposed trusses cathedral ceilings or specialty open ceilings. Images courtesy simpson gumpertz heger.

The quest for greater energy efficiency in buildings has led to increasing interest and need for insulation improvements in hvac equipment more airtight construction new materials and assemblies. Senior engineer manager at icynene john broniek makes the case for the unvented attic assembly and why insulating the underside of the roof makes sense. Like ordinary roof trusses scissors trusses come with or without a raised heel sometimes called an energy heel. With a regular roof insulation isn t a problem.

In either case you will need to follow the general steps below to insulate your garage roof. However if you have a cathedral style garage roof you will need a scaffolding to get into the upper areas of the roof. Then feed the rolled insulation under wires and pipe if either is present. It creates a breeding ground for mold and mildew and ruins the air trapping pockets that block heat flow.

Roof insulation configurations for unvented rafter truss assemblies. If you have a flat garage roof and an attic above you can install the garage insulation from below using a standard ladder. Make sure it is flush against the wood as even a 1 inch gap can cause a 20 percent heating loss. Water is insulation s enemy.

For rolled insulation place it between roof rafters. If the plastic sheeting is in pieces overlap the pieces. A variety of insulation materials can be used to insulate scissors truss roofs as long as. The relatively costly application for example can also save money by lowering your energy bills and enabling you to add your own insulation with a contractor s help.