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Schematic of exterior insulated roof assembly

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Wrong - The roof insulation panels for this building were not installed in multiple layers with joints offset. The snow melt pattern shows thermal bypasses at the insulation panel joints.

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Roofing membrane is installed over polyisocyanurate rigid foam insulation and insulation cover board that has been cut to fit around locations for blocking for the PV system rack

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Water Managed Roof – Re-roofing and Adding Insulation Over a Sloped Roof

Guide

Guide describing how to re-roof an existing home with a sloped roof and add insulation above the roof deck.

Water Managed Roof – Re-roofing and Adding Insulation over a Flat Roof

Guide

Guide describing an approach to re-roofing an existing flat roof to improve thermal, water, and air control performance.

Right - These roof insulation panels are installed in multiple layers with joints offset both vertically and horizontally. The plywood nail base fastened to the roof framing holds the insulation layers together snuggly thus minimizing gaps

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Sheathing is removed from a flat roof to retrofit with air sealing, insulation, and water control layers

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Polyisocyanurate rigid foam insulation is installed in multiple layers with staggered, taped seams over the flat roof

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Technology Solutions Case Study: BA-1312: Application of Spray Foam Insulation Under Plywood and OSB Roof Sheathing

Case Study

Case study describing research about spray foam roof insulation and moisture management.

The base of the plywood parapet is air sealed with spray foam and fibrous insulation is installed in the rafter cavities in this flat roof retrofit

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Cost Analysis of Roof-Only Air Sealing and Insulation Strategies on 1-1/2 Story Homes in Cold Climates, Minneapolis, MN

Reference

This case study describes costs associated with the External Thermal and Moisture Management System developed by the NorthernSTAR Building America Partnership for retrofitting roofs with rigid foam over the roof deck, especially on one and a half-story homes.

Wood blocking for future PV panel installation is installed in the layers of polyisocyanurate rigid foam insulation during a flat roof retrofit

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Step 1. Apply roof underlayment over roof deck and up the sidewall over the rigid foam insulation

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This house design in the Hot-Humid climate uses a slab foundation, masonry walls, and an Exterior Insulation Finish System (EIFS) cladding.

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Step 5. Apply self-adhesive flashing over top edge of the wall flashing, diverter, and rigid foam insulation

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A roof drain is installed in an existing flat roof retrofitted with above-deck rigid foam insulation that is integrated with new air and water control layers

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The wood blocking for future PV panel installation extends above the surface of the top layer of polyisocyanurate rigid foam insulation installed as part of a flat roof retrofit

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The mechanical curb for a skylight is integrated with the water management and air control layers on a flat roof retrofitted to include new above-deck rigid foam insulation

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Roofing paper protects the top of the new plywood parapet while the base of the parapet is air sealed with spray foam and fibrous insulation is installed in the rafter cavities in this flat roof retrofit

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Retrofit an existing roof by installing rigid foam, new moisture and air control layers, new sheathing, and new cladding plus cavity insulation in the roof rafters to create an unvented attic

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Wrong: Closed-cell spray foam roof insulation was not thick enough to meet IRC levels so the foam surface is colder than the dew point of the interior air and condensation formed on surface of the foam

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Existing low-slope (“flat”) roof and brick masonry walls with a new fully adhered air barrier membrane plus polyisocyanurate rigid foam insulation and a roofing membrane water control layer

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This roof is hurricane proofed with a coated insulated OSB deck sheathing that is caulked and taped at all seams with a water-resistant tape, then fully covered with a peel-and-stick membrane, and asphalt shingles.

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Existing flat roof and wood-framed walls are retrofitted with a new fully adhered air barrier membrane plus polyisocyanurate rigid foam insulation and a roofing membrane water control layer

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Construct Roofs and Attics for Ice Dam Prevention

Guide

Guide describing how ice dams form and how roofs can be constructed to prevent them.

Technology Solutions Case Study: Field Testing an Unvented Roof with Asphalt Shingles in a Cold Climate

Case Study

Case study describing an experiment to build and instrument unvented test roofs using air-permeable insulation in a cold climate and to analyze the moisture effects over time.