Unvented Pitched Roof Insulation

Enhancing roofing material life span by reducing sheathing temperature.

Unvented pitched roof insulation. 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. An unvented assembly can perform well but it s important to get the details right to avoid sheathing rot. Controlling ice damming by keeping the roof cold. Unvented flat roofs a technical discussion flat roofs have often been built with the insulation all on top of the vapor closed drainage plane as this avoids dew point condensation issues inboard of the roofing.

We have a wide range of roof insulation products including flat roof insulation tapered insulation and pitched roof loft insulation. In your scenario the space between the rafters can serve as this ventilated cavity allowing you to attach insulation continuously to the underside of the rafters. 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. There are traditionally four main reasons for venting a roof.

However in many situations the insulation may need to be primarily or entirely below the flat roof membrane and between the roof joists if so what are the best options. In the most recent issue of fine homebuilding martin holladay wrote a piece on insulating unvented roof assemblies. We re big fans of fine homebuilding. Removing moisture from roof cavities structural members sheathing and insulation.

Inclined along the line of rafters warm roof or positioned within the roof structure to form an insulated void room in roof which can result in warm and cold roof areas. Installed a new fully adhered membrane to the top of the old board sheathing prior to adding all that rigid insulation. Roof edge detail overhang extended to hide the thickness of the over roofing rigid insulation. In pitched roof construction thermal insulation can be placed horizontally at ceiling level cold roof.

Insulating unvented roof assemblies. When insulating pitched roofs with old style felt it is important to maintain a minimum 50mm well ventilated cavity between the felt and the top of the insulation. We agree that avoiding sheathing rot is critical and that air permeable insulation such as fiberglass or cellulose cannot be used alone. Gable end detail overhang cut and then rebuilt to hide the thickness of the over roofing rigid insulation.

We also have insulation boards suitable for more specialist roof applications for example inverted roof insulation and balcony insulation. 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.