Insulating Sloped Roofs

If you plan to insulate a sloped roof you need to decide if you want a vented or an unvented assembly.

Insulating sloped roofs.

By martin holladay issue 256 dec 2015 jan 2016. Currently the built up asphalt roof is installed over homasote or something similar and a roof deck made of wood planks. Low slope and steep slope unvented roof systems i e. Additionally insulation serves as a way to enhance sound proofing on the uppermost envelop of your house.

He plans on replacing the low slope built up roof with an epdm membrane and the question is how to insulate it correctly. There are lots of ways to insulate a low slope roof and most of them are wrong. Because of limited space between the roof sheathing and ceiling joists a low slope shed roof can be difficult to insulate properly. Rigid board insulation rigid board insulation is the most common type of insulation used in low slope commercial roofing.

Eric dymond lives in a 1920s baltimore row house that needs a new roof. Insulating a sloping roof. Air permeable insulation such as fiberglass batts dense packed cellulose or blown. Or sprayed polyurethane foam spf.

In older buildings the usual method is to install fiberglass batts or cellulose on top of the leaky ceiling with a gap of a few inches or sometimes a few feet between the top of the insulation and the roof sheathing. Dual purpose structural deck and insulating planks. It s worth insulating the sloping insides of a pitched roof in order to conserve heat if the space is to be used for anything except simple storage. Insulation value optimization for low slope roofs bu i l d i n g en v e l o p e te c h n o l o g y sy m p o s i u m no v e m b e r 16 17 2018 tay l o r 3 roof zone fastener density loss from designed r value per ft2 per m2 gypsum cover board polyiso cover board field 0 375 4 04 13 95 12 82.

Updated on april 8 2016. However architects of these compact roof assemblies must consider vapor permeance and. Lightweight insulating concrete lwic. An unvented assembly can perform well but it s important to get the details right to avoid sheathing rot.

In this energy smart homes article senior editor martin holladay explains how to insulate a vented low slope shed roof using a combination of intake vents and cupolas. The insulation used in low slope roof assemblies typically falls into one of the four categories. Saint gobain insulation uk manufacture and supply glass mineral wool slabs and rolls along with rigid polyisocyanurate pir boards that can be considered suitable for a wide range of applications across pitched roofs whether you re looking to insulate at joist level or at rafter level in your pitched roof construction. 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.