Insulation Above Exposted Roofing

You can prevent this by installing foam insulation board against the underside of the roof between the rafters.

Insulation above exposted roofing. The exposed edges of the 3 layers of rigid insulation are to be sealed with another layer of membrane. Video of the day volume 0. 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. More insulation is needed above the roof deck in colder climates and where indoor relative humidity is above 35 in winter.

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. With this kind of roof the insulation follows the slope of the roof. However most cathedral ceilings and low slope flat roofs are insulated roof assemblies. 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.

Insulated roof assemblies can be vented or unvented. The insulation for exposed rafters is installed on the exterior side of the finish ceiling. 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. High r value unvented roof assemblies will require a proportionally larger amount of insulation above the roof deck for condensation control.

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. Generally 40 of the total assembly r value should be above the roof deck. 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. Insulating your roof and attic space will help retain energy in your home often leading to cost savings and comfort improvement.

You don t have to build interior soffits. This is often a layer of tongue and groove boards nailed to the exterior side of the exposed rafters. It s perfectly ok to put the ducts in the attic truss space if you want since these ducts are inside the home s thermal envelope. Isoboard thermal insulation fitted as a ceiling following the roofline allowing the opportunity to create additional space or a liveable loft conversion.