Insulating A Non Vented Flat Roof

If you don t want to use sips or nailbase read this article tolearn the four basic approaches to insulating unvented roof assemblies.

Insulating a non vented flat roof.

In this case you can learn a lot from foam tech s article vented vs. But spray foam insulation used at the underside of the roof deck would need to be covered by a thermal barrier and intumescent coatings are commonly used. For such constructions the principles and benefits of unvented attic construction are similar to that occurring in a single family residence. 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.

How much ventilation does a flat roof need. Foam insulation can play an important role in both vented and un vented roof assemblies. Unvented roof assemblies should be insulated either with air impermeable insulation rigid foam or spray polyurethane foam or with a combination of foam and air permeable insulation. Unvented roofs which provides a detailed explanation of each.

Cold roofs have insulation beneath the. Nail 1 furring along every rafter side against the roof deck. Basically the term cold roof refers to a traditional roof or vented roof while hot roof refers to a roof that is not ventilated and which has foam insulation attached directly to the roof sheathing. Hot roofs have the roof deck then insulation then the roofing material.

The answer depends on the type of roof you have. Insulation mineral wool rests on the interior ceiling and is approx 4 thick and provides minimal insulation r 11. Cut and insert 1 or thicker high r foam insulation sheets r 8 per inch against the furring giving a 1 or greater air path between the insulation and the roof deck under the cathedral ceiling. Low slope and steep slope unvented roof systems i e.

There are about 10 between roof decking to interior ceiling. Any type of roof from tpo to epdm can be either hot or cold. This space is currently accessible only by removing facia rim joist on soffit. Mid century modern home has flat torch down 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. It depends on where the insulation is installed. A non vented flat roof. Insulation and air barrier are applied directly to the underside of the roof deck are common in applications where designers are seeking cost effective and energy efficient roof assemblies.

In a vented roof foam can seal the openings and serve as an air barrier and a vapor retarder in addition to its insulating function. Preventing moisture is essential for having a properly functioning un vented roof.