Multi-layering should be the talk of the town regarding insulation! NASA has perfected MLI blankets enabling us to get to and from space safely, protecting the equipment inside and out, the capsules, landing vehicles, rovers, telescopes and astronauts. My question is, why has it taken the rest of us so long applying it to so many fields?
Multi-layering provides passive thermal control by reducing losses/gains due to thermal radiation. Radiant barrier is radiant heat control and used in layers, will reduce conduction, break the thermal bridge, eliminate the need for thermal insulation and act as either a vapor barrier or air barrier.
There are many applications for multiple layering techniques. For example, sound blocking. Insulation for sound proofing must be done by separating surfaces. With sound, a continuous material will act as an acoustic bridge moving vibrations from one room to the next. Note, the need to separate surfaces which is similar with radiant barrier bubble separating when applying multi-layering and having that critical airspace.
Radiant barrier bubble foil used in multiple layers between floor joists will not only fix the heat loss problems but will provide reasonable sound deadening properties as well. This is best done in three layers which, will eliminate the need for thermal insulation.
Wall assemblies can be multi-layered as well. Instead of fiberglass batt, layers of radiant barrier single bubble foil/foil can be used similarly as the illustration below. The assembly could be, sheet rock, thick furring strips, 1 layer attached to spacers on top of previous layer attached to studs. In between studs, 3 layers of bubble with appropriate air space then there would be house wrap and a last final layer of perforated radiant barrier on furring strips which would be attached to the Tyvek or similar, providing another water plane moisture control, an air barrier, radiant heat control and it will break the thermal bridge of the wall studs. Sounds like a mouthful of complicated layering but means a world of difference for the structure and creature comfort and energy savings. The old saying, “buy cheap, buy twice,” works for insulating, big time. Do it right in the beginning with more financial outlay initially but avoiding costly repairs later and, over time, energy savings, unless we have Nikola Tesla’s free energy powering our homes.
Multi-layering for roofs can be done effectively with radiant barrier. One method is to use the the 3-layer Tempshield single bubble application and on the last layer, attach it to the spacers under the truss to break the thermal bridge!
Radiant barrier and fiberglass, a blanket in a sense (Smart-Barrier), could be used in walls as the illustration below, providing radiant heat protection, a vapor barrier and moisture protection, sound proofing and, thermal bridge protection.
A well-insulated roof equates to layers such as, air space, venting, vapor control, batten/insulation space, air space and radiated heat control.
Radiant barrier blankets work great as a multi-layer thermal insulation and sound dampening while also reducing the radiant heat. The advantage of using these blankets is they do not compress and lose R-value as moisture and years progress. These work great between joists or studs, ceilings, between floors etc.
A great concept and application I found while doing some research, was radiant barrier applied to the top and bottom of a honeycomb structure. See photo below. This is another fantastic application because all the air spaces provided by the honeycomb structure, produces an exceptional level of thermal insulation. The radiant barrier above and below provides vapor resistance, air barrier as well as radiant from above and radiant heat from below. This is most likely an extremely light weight product compared to standard insulation and easy to cut manually producing no dust or fiber inhalation issues.
The goal of showing all these various multi-layering applications, was to prove that we have barely touched the surface of what radiant barrier can do when used together with other products in multi-layer systems.
We all know building codes are the minimum requirements for a structure meaning, if a builder does just to code, you will get a low-quality home. We need to incentivize code changes to higher quality applications and levels in construction.
I for one, am fed up with cheap, garbage-quality home construction where there are thermal bridges throughout, hot and cold slab, leaky cheap HVAC installation where the ducts are exposed to extreme attic heat and cold, zero attic insulation and zero radiant barrier (home is 15 years old and radiant barrier has been around for residential construction for over 30 years) use to prevent the intense attic heat and Southern wall exposure. Simple fixes but not after the home is finished.
Breaking thermal bridges should and must be basic code and radiant barrier house wrap, or bubble foil used in other areas, is the fastest and easiest way to accomplish this.
Radiant barrier in multi-layers addresses, vapor, air, radiant heat, sound deadening, and provides thermal insulation. Addressing all these chronic and classic issues in homes and other buildings, before they happen, is working smarter. Working smarter means educating oneself then assessing your situation and needs to find and adjust applications that will work. Sadly, one must remember most advice comes with someone wanting to push sales of a certain product.
I am new to the radiant barrier world as well as construction and have worked to educate myself and understand this “new world.” I see this is not a one-size-fits-all and, filtering out the paid negative publicity and articles, is crucial to finding what is real and what is strong-arming to keep an edge on the market in an industry. Once you are left with bare bones information, solutions and applications are easy to find and figure out. More is not better with insulation. There is a very fine line of just the right amount of air space to too much air space creating vortices and changing the R-value. Being smart is key to reaping all the benefits this product can provide. The beauty of radiant barrier is that it works in the simplest of systems; there is nothing difficult, complicated, or toxic when working with radiant barrier. Imperfect installations will still work, I can attest to that with the 20-degree difference from my garage interior to outside air.