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.
Flat roof insulation requirement.
The tables below show the suggested u values in england wales and scotland.
A common differentiating criteria between different types of insulation is the amount of r value they provide when correctly installed.
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.
See the department of energy s doe ranges for recommended levels of insulation below.
Insulation for flat roofing is used to make a structure more energy efficient and minimise heat loss.
Flat roof insulation.
With a flat roof this issue does not arise but the u value constraint and the amount of insulation needed is just the same.
There are many options available to fulfil this requirement as you will find out below.
An r value tells you how well a type of insulation can keep heat from leaving or entering your home.
This will help to conserve energy and ensure thermal comfort is maintained within the building.
Cold roofs have the waterproof layer placed directly onto the roof deck and the insulation inside the roof just above the ceiling.
There are two types of flat roof.
Insulation r values vary based on the type thickness and density of the insulation material.
The higher the r value the better the thermal performance of the insulation.
In this case ventilation is required and the roof can still become wet with condensation which may cause materials to decay.
Achieving a u value of 0 20w m meaning your roof will be better insulated than your walls will need 120mm thickness of rigid foam or 200mm of mineral wool or natural insulation.
Cold roofs and warm roofs.
The required u value will depend on the location of the project england scotland or wales type of building domestic or non domestic and the application floor wall or roof.
Insulation ratings are measured in r values per inch of thickness.
Recommended home insulation r values.
The higher the r value the better the insulation.
Another major performance issue with insulation and energy savings is its air sealing capability.
R value is a measure of insulation s ability to resist heat traveling through it.
Laying flat roof insulation.
As a rule any roof with a pitch below 10 is classified as a flat roof.