Flat Roof Insulation Requirements

How much ventilation does a flat roof need.

Flat roof insulation requirements.

Cold roofs have insulation beneath the roof deck which is beneath the roofing material. A qualified roofing contractor will be able to advise on this but here are some of the main guidelines. The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. Continuous insulation zones ashrae 90 1 ashrae 189 1 igcc ibc iecc 2004 2007 2010 2013 2016 2009 2011 2014 2012 2015 2009 2012 2015 0 25 1 15 20 2 15 20 25 3 15 20 25 4 15 20 302535 5 15 20 302535 6 15 20 3035 7 15 20 3540 25 8 20 3540 25 minimum r value non residential above roof deck.

From there the flat roof system you choose will determine the materials you apply. The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures. While expensive the best insulation is polyiso rigid foam. Typical recommendations for exterior walls are r 13 to r 23 while r 30 r 38 and r 49 are common for ceilings and attic spaces.

See the department of energy s doe ranges for recommended levels of insulation below. A cold roof or hot roof. A note to consider before construction. We recommend having at least 20 r value worth of material for optimal energy efficiency.

You can expect to pay about 55 100 sq ft. If insulation is installed below the flat roof deck this is called a cold roof. There must be a slope of 1 80 part h of the building regulations regarding drainage state that water should drain to one or two edges waterproofing should extend up the adjacent walls at least. Insulation requirements for roofs are therefore spread across ibc chapters 12 13 and 15.

In most cases there will not be a loft in a building that features flat roofing. Hot roofs have the roof deck then insulation then the roofing material. It is top quality and the most cost effective product for your flat roof. For a 1 inch board equivalent of 6 r value.

It depends on where the insulation is installed. Attic space enclosed rafter or joist space above normally occupied and conditioned interior space assemblies as an economical arrangement of roofing and insulation materials. If the insulation has a sufficiently high vapour resistance a separate vapour control layer may not be required and the. Where insulation is mechanically fixed the fixings must be of sufficient length to.

The answer depends on the type of roof you have. The insulation may be fully or partially bonded to the vapour control layer or laid loose. Applicable roofing assemblies designers may view unvented attic i e. This means that your approach to insulation will differ from a standard pitched roof.