What is a deck on a roof called?
The roof over a deck is usually called a patio cover. This attached structure provides protection from sun and rain and can either have a solid or open roof. Pergola is another name for deck or patio roofs. This is typically characterized as an open roof that’s supported by posts or columns.
What is vapor barrier roof?
The purpose of a vapor retarder is to minimize or reduce water vapor diffusion into a low-slope roof system or wall system. In other words, it is used to prevent the formation of condensation in a low-slope roof system or wall system. Consequently, a vapor retarder in a roof assembly is also acting as an air barrier.
Does radiant barrier insulation Really Work?
Some studies show that radiant barriers can reduce cooling costs 5% to 10% when used in a warm, sunny climate. The reduced heat gain may even allow for a smaller air conditioning system. In cool climates, however, it’s usually more cost-effective to install more thermal insulation than to add a radiant barrier.
What is an insulated roof deck?
Roof Deck Insulation Cold roofs have insulation between the rafters, allowing for ventilation space below your roof deck. Ceiling insulation is then installed on the attic floor. Make sure there is adequate air flow from the eave vents to the attic area.
How do you support a deck roof?
Most deck roofs require separate footings from the deck to support the weight of the roof throughout the seasons. For deck roof posts, dig holes for the roof posts and pour cement to keep them secure. Always check the local codes.
Does my roof need a vapor barrier?
Plastic vapor barriers should only be installed in vented attics in climates with more than 8,000 heating degree days. All attics — vented or unvented — should have an air barrier (a properly detailed airtight drywall ceiling, for example) regardless of climate.
How does radiant barrier roof decking work?
Radiant barriers and reflective insulation systems work by reducing radiant heat gain. To be effective, the reflective surface must face an air space. The hot roof material then radiates its gained heat energy onto the cooler attic surfaces, including the air ducts and the attic floor.
What should I put between roof and insulation?
A vent baffle should be installed between the insulation and the roof decking to maintain the ventilation channel. Consider using high-density R-30 batts, which are as thick as R-25 batts, but fit into 2×10 framing.
How do you insulate a roof deck?
Insulation can be applied to the underside of the roof deck at any time, either directly after a roof replacement, or at a later date. The most common method of insulating this area uses a spray foam insulation.
How does radiant barrier roof decking help you?
Radiant barriers reduces the radiant heat transfer from the roof to the interior of your attic. Radiant barriers are graded on three levels: Emmisivity – This is expresses as a number between 0 and 1, and it is the amount of radiant energy that is emitted back onto a black surface of equal area and temperature.
Why is there no air barrier in a roof?
This helps explain why warm, moist interior air (e.g., 75º F, 50 percent relative humidity) infiltrates up into a roof system when there is no air barrier. There can be other reasons why this happens, like the stack effect, membrane billowing, and internal pressurization from mechanical systems.
How are vapor retarders and air barriers related?
With the new focus on air barriers, designers may be quick to add them to roofing systems. Recognize that all vapor retarders are air barriers, but not all air barriers are vapor retarders. Some air barriers are vapor open and allow moisture to escape. There are three classes of vapor retarders.
Can a gypsum board be used as an air barrier?
A gypsum-fiber board has a perm rating of approximately 24 to 30 perms, depending on thickness, and if this board is fastened to a steel deck and the joints and transitions are taped, it could be an effective air barrier that allows some drying.