Ridged Insulation Against Plywood Roof

Water is insulation s enemy.

Ridged insulation against plywood roof.

The illustration shows two layers of osb or plywood roof sheathing. Look for water stains on the roof sheathing or damp or moldy spots on attic joists and existing insulation as a clue to where leaks might be. Plan to replace asphalt shingle roof with standing seam metal. Nail it around the edges with roofing nails.

Techni flo engineered ventilation system features a unique design. The roof deck can be plywood metal concrete or wood planks. Condensation control is most often accomplished by installing rigid foam above the roof deck or by installing air impermeable spray foam insulation directly against the underside of the roof deck. Rigid foam insulation installation prepare roof deck.

The code also allows for air permeable insulation such as fiberglass or cellulose to be used under the roof deck as long as rigid foam is used. 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. Acfoam crossvent is a thermally efficient cross ventilated non structural composite roof insulation. Install them using panel adhesive or screws.

A lower layer conventionally nailed to the rafters and an upper layer installed as a nailing surface for the roofing material on top of the rigid foam. Smaller sizes are also available. They re much lighter and easier to work with than plywood sheets. 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.

The problem arises with moisture. Rigid insulation under a cool roof in zone 3. I live in charleston sc in an old 1858 3 story wooden house. The moisture is held in place by the insulation which allows for damage to the framing and other building components.

Consisting of acfoam ii or acfoam iii polyiso insulation board and osb or cdx plywood separated with and bonded to 5 individual expanded polystyrene vent spacer strips. Atlas offers accessories to promote airflow. Start at the bottom of the roof and place the first piece of rigid foam insulation against the metal flashing starting at the center line. It creates a breeding ground for mold and mildew and ruins the air trapping pockets that block heat flow.

Installed on the roof exterior foam makes the living space below more comfortable and reduces the likelihood of ice dams. Box out light fixtures. Working with home insulation boards insulation panels typically come in 4x8 foot sheets. Appreciate this extremely helpful blog.

The first step with roof installation is to prepare the roof deck by getting rid of all dirt dust and contaminants. Currently there is no insulation anywhere and the third floor basically an enclosed attic gets crushed by heat in the summer. The bottom layer of a single ply membrane roofing system is the roof deck or substrate.