Insulating The Roof Deck

If there is a roof leak the insulation will be damaged by the water leaving you with less insulating value.

Insulating the roof deck.

The ratio of insulation above the roof deck or air permeable insulation below the roof deck is a matter of climate and interior conditions. You may also insulate your roof to help regulate the temperature in an attic that is a part of your living space. 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. Unless you re using mineral wool insulation or your fixtures are rated safe for contact with any type of insulation don t allow the material to touch or cover recessed cans or lights from the floor below it s a fire hazard.

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. Box out light fixtures. Typically this would be achieved by adding polyiso insulation above the plywood deck. Whether or not there is an inner roof lining and the total thickness of the roof structure.

Also the higher the indoor humidity the more insulation is needed to avoid condensation. The problem arises with moisture. Generally more insulation is needed for condensation control in colder climates. T he problem with the insulation against the sheathing expands.

There are different roof decks that require different insulation techniques. Insulating the roof is a priority if the ceilings of your home happen to be part of the roof deck as is the case with cathedral ceilings. The moisture is held in place by the insulation which allows for damage to the framing and other building components. Materials commonly used for the insulation of the roof deck include.

Add insulation above the roof deck this approach fits current building science thinking in terms of putting the thermal control layer on the outside of the building structure. Rigid foam insulation boards. The technically correct approach depends on a number of factors. Install baffles or make sure there s 1 minimum of airspace between the roof deck and insulation.

Air sealing hot roofs is critical. Cold roofs have insulation between the rafters allowing for ventilation space below your roof deck. The right thickness would need to be calculated to move the dew point above the plywood deck where air infiltration is minimized. If your attic is often used or perhaps you plan to convert it in the future you will need to insulate the inner surfaces of the roof.