Insulation made with top-quality materials also keeps pollutants, harmful toxins, and allergens at bay drastically improving the indoor air quality in your home. These protective layers are also water resistant, preventing the growth of mould and mildew, which harm the respiratory system.

The thickness of insulated roofing panels depends on a very few factors, such as the climate you live in, the kind of insulation you opt for, and a numerical figure called the R-value.

So, what kind of insulation do you need? How thick should the insulation be? How does it affect residential roofing installation? Let’s take a closer look.

Understanding R-Values of Insulated Roofing Panels:

An R-value in roofing isulation is given to the insulation materials, where the “R” stands for resistance to heat flow.

It is assessed every inch of thickness and describes how impactfully insulation can prevent heat from leaving or entering your home. R-values depend on insulation thickness, the density of materials, and the type of insulation.

Higher R-values correspond to better climatic control and also higher energy efficiency. But they can be much more expensive. Materials over R60 provide specifically top-notch insulation, while those below R30 will be cheaper but less effective.

 

Understanding R-Values:

Some states recommend an R-value figure the minimum roof insulation thickness should be evaluated on an R-value of a minimum R49. This figure can change depending on whether you are installing a new insulation barrier or repairing an existing one.

To determine a particular material’s R-value, divide its thickness by thermal conductivity. Thicker materials have a higher R-value, while materials with lower thermal conductivity are more effective at conditioning air.

 

Choosing the Type of Insulated Roofing Panel Material:

The third factor that impacts the insulation thickness is the roofing materials you can use to trap the heat. Here are some of the most popular and much effective options:

 

• Spray Foam Insulation:

A more expensive form of insulation involves adding a polyurethane or latex spray layer under your roof. It provides significantly higher R-values and is water-resistant. However, it comes at a much higher cost—installing one that meets the minimum insulation thickness of a flat roof can run you to about $10,000.

 

• Batt Insulation:

Crafted from the popular material fibreglass, batt blanket insulation comes in various R-value options. It is a mcuh cost-effective than spray foam insulation. However, it will require many layers to achieve the ideal thickness the structure needs.

 

• Foam Board Insulation:

Created of materials like polyurethane or polystyrene, this type of insulation has a reasonably high R-value. However, it may require an additional coating of a fire-resistant material, such as gypsum sheathing.

The roof insulation thickness should be lower than batt insulation to meet energy-saving requirements.

 

• Blown-in Insulation:

This type of insulation can be built from different materials, from fibreglass to cellulose. The name refers to the process by which it is created: the material is blown into a space through a tube, making it possible to insulate even the hard-to-reach areas.

While fibreglass requires less insulation thickness to be effective, there are better options for structures in colder climates. Cellulose needs a thinner layer to be impactful but is considerably more flammable than fibreglass.

Many other procedures and materials can be used to insulate a roof. This brings us to the final question: What should be the recommended roof insulation thickness based on the R-value of the materials used?

 

Determining Insulation Panel Thickness:

Every material has a different R-value per inch of thickness.

For example, foam board insulation ranges from R3.6 to R5.8 per inch. In this case, 10 inches of the insulation thickness will provide you an R-value of R38 to R58.

Identify the climate zone of the building and the recommended R-value to determine the ideal insulation thickness. Similarly, a roof in a colder climatic zone must be between 16 to 18 inches.

This roofing cost calculator can give you a better idea of how much this will cost.

 

In Conclusion:

Ultimately, figuring out the right roof insulation thickness can be very complicated and is best left to a professional roofing company.

If you have more specific questions related to flat roof thickness or need more general roof installation tips, we recommend contacting us at Ezi Batten.