Insulation Above Exposted Roofing

Insulating in and around your roof attic space also prevents long term damage from moisture build up or ice damming which results from the warm air trying to escape through the apex of the roof but instead heating up the snow.

Insulation above exposted roofing.

Box beam gable framing new gable overhang is framed in the form of a box beam hanging off of a new layer of roof plywood roof sheathing cantilevered over the top of the 3 layers of rigid insulation. This is often a layer of tongue and groove boards nailed to the exterior side of the exposed rafters. Find your zone on the map and then use the chart to determine the level of insulation you need to properly insulate your attic walls floors and crawlspaces. The exposed edges of the 3 layers of rigid insulation are to be sealed with another layer of membrane.

Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation. More insulation is needed above the roof deck in colder climates and where indoor relative humidity is above 35 in winter. Insulated roof assemblies can be vented or unvented. With this kind of roof the insulation follows the slope of the roof.

High r value unvented roof assemblies will require a proportionally larger amount of insulation above the roof deck for condensation control. The insulation for exposed rafters is installed on the exterior side of the finish ceiling. One drawback to this is that the layer of insulation placed above the ceiling is missing which can subject the area of the house with the exposed rafters to extreme temperature changes. If all of your insulation is above the roof sheathing and if you have a roofing membrane above the insulation then you already have an airtight insulated roof assembly.

You don t have to build interior soffits. Following ten years of extensive testing isoboard thermal insulation has developed a proven solution to fixing its thermal insulation boards above rafters trusses or beams. However most cathedral ceilings and low slope flat roofs are insulated roof assemblies. Video of the day volume 0.

Isoboard thermal insulation fitted as a ceiling following the roofline allowing the opportunity to create additional space or a liveable loft conversion. Generally 40 of the total assembly r value should be above the roof deck. A roof over a vented unconditioned attic does not need to include any insulation. Additionally insulation serves as a way to enhance sound proofing on the uppermost envelop of your house.