Insulation Above Exposted Roofing

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Insulation above exposted roofing.

This is often a layer of tongue and groove boards nailed to the exterior side of the exposed rafters. A roof over a vented unconditioned attic does not need to include any insulation. 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.

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. 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. However most cathedral ceilings and low slope flat roofs are insulated roof assemblies. Generally 40 of the total assembly r value should be above the roof deck.

Additionally insulation serves as a way to enhance sound proofing on the uppermost envelop of your house. More insulation is needed above the roof deck in colder climates and where indoor relative humidity is above 35 in winter. Insulating your roof and attic space will help retain energy in your home often leading to cost savings and comfort improvement. 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.

You don t have to build interior soffits. Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation. You can prevent this by installing foam insulation board against the underside of the roof between the rafters. 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.

Isoboard thermal insulation fitted as a ceiling following the roofline allowing the opportunity to create additional space or a liveable loft conversion. 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. The exposed edges of the 3 layers of rigid insulation are to be sealed with another layer of membrane. 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.