Flat Roof Insulation Requirements

For a 1 inch board equivalent of 6 r value.

Flat roof insulation requirements. There are two main types of flat roof that require different approaches to installation. Depending on where you live and the part of your home you re insulating walls crawlspace attic etc you ll need a different r value. 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. Find your zone on the map and then use the chart to determine the level of insulation you need to properly insulate your attic walls floors and crawlspaces.

Be durable and suitable for external use. Mineral wool rolls are ubiquitous and cheap meaning a whole roof on a standard home could be insulated to the recommended 270mm with a spend of little more than 200. Be able to cope with extremes of temperature and uv light without deterioration in thermal performance. Insulating a roof is perhaps the easiest of all the energy saving home improvements.

The insulation material for a warm flat roof should. 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. A qualified roofing contractor will be able to advise on this but here are some of the main guidelines.

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 is placed in between the joists underneath the roof surface. It is top quality and the most cost effective product for your flat roof.

It s also within the capability of most diyers although not the most pleasant of tasks. The material that works best depends largely upon preference in a given situation. From there the flat roof system you choose will determine the materials you apply. Be able to provide support for or.

While expensive the best insulation is polyiso rigid foam. Insulation material is placed on top of the roof rather than in between the ceiling and the decking. Be able to resist pressure from any anticipated foot traffic. 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.

Like other roofs insulating a flat one requires ample ventilation a vapor barrier and sealed bypasses. Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation.