HeatBloc-Ultra Phoenix AZ | Radiant Barrier Insulation | Heat Barrier Coatings by Barrier Insulation, Inc. Statewide Arizona

HeatBloc is an aluminum colored, water-based, low emissivity (low-e) coating. When applied to building materials such as plywood, OSB or plasterboard, HeatBloc lowers their surface emissivity to 0.25 or lower, thereby blocking over 75% of the radiant heat trying to enter the home. It is classified by ASTM as an Interior Radiation Control Coating (IRCC).

HeatBloc radiant heat barrier works by changing the emissivity of the surface where it is applied. Building products such as wood, brick, and plasterboard have high emissivities (0.7-0.95). When heated, they radiate most of their heat to cooler surfaces by allowing the heat to penetrate the roof into the attic and from the attic into the house. HeatBloc lowers their surface emissivity to under 0.23, lessening their ability to radiate heat and therefore letting less heat penetrate the roof into the attic.

Heat penetrates buildings in three ways: conduction, convection and radiation. Radiation is the transfer of heat by electromagnetic waves known as thermal radiation. Thermal radiation is a form of invisible light that travels through the air from a warm to a cool surface. Warm surfaces, such as roof decks warmed by the sun, will radiate or emit their heat to cooler interior building surfaces. Radiant heat barriers address heat flows by radiation. A radiant heat barrier is a low-e surface placed in the path of thermal radiation that blocks heat transfer.

Emissivity is the ability of a surface to radiate or emit energy in the form of long wave electromagnetic radiation. It is represented by a value from 0 to 1. The closer the value is to 1, the less effective the surface is at impeding radiant heat transfer. Wood has an emissivity of 0.90. Thus, when wood is heated above the temperature of surrounding surfaces, it will tend to transfer 90% of its heat energy by radiation. HeatBloc, when applied to most non-porous surfaces, will decrease the surface emissivity to 0.25 or lower, allowing less than 25% of the heat energy to be transferred by radiation.

To function effectively, a radiant heat barrier must face an airspace of 1″ or greater. A radiant heat barrier will not function if sandwiched between two solid surfaces. HeatBloc, when installed on the underside of roof decking, normally faces downward into the attic. If insulation is installed in the cavity formed by the roof trusses and roof decking (as in a cathedral ceiling), at least 1″ should be allowed between the top of the insulation and the HeatBloc surface.

Yes! HeatBloc allows water vapor to permeate, and does not trap water vapor within roof decks or sidewalls. This is vitally important in attic conditions.