Understanding 3" Polyiso Insulation Board and Where to Find the Best

You’ve narrowed down your preferred type of insulation for your new construction or remodel project, and now it’s time to nail down a supplier and get a great price on 3” polyiso insulation. Finding out where to buy polyiso insulation can be tricky if you’re looking in the wrong places. Here, we cover where to buy 3” polyiso insulation for your home or commercial building.

Why 3” Polyiso Insulation?

Polyiso comes in a multitude of thicknesses, ranging from ½” up to over 4”. So, why would you choose 3” polyiso insulation? You may want to use it if you’re trying to achieve R20 with your building envelope (which includes your walls, roof, or foundation). Rmax Thermasheath® polyiso insulation, for example, exceeds the R20 minimum, coming in at R20.3 with their 3” thick boards.

Polyiso is a versatile building material that achieves premium energy performance with a lower profile. Here are the facts that demonstrate areas where polyiso outperforms other types of insulation:

  • High R-Value per Inch

  • Ease of Installation

  • Multiple Facer Types Available

  • Can Act as an Air and Vapor Barrier

  • Fire Resistant

  • Compatible for use with the entire building envelope

High R-Value Per Inch

Polyiso carries a thermal resistance R-value of R6.0 per inch. It far exceeds other building materials, including fiberglass, mineral wool, and other types of rigid insulation.

Easy to Install

No special equipment or experience is required to install polyiso insulation. It can be fastened to surfaces with screws and oversized plates, adhered, or even loosely laid into place.

Facer Options

Polyiso insulation is unique when compared to other rigid board insulation types because the polyiso foam core is sandwiched between two facers, whereas other types of insulation have no facers. Polyiso facers can include reinforced aluminum, plywood, and glass-reinforced felt.

Air and Vapor Barrier Compatible

As mentioned above, the facer material on 3” polyiso boards can be aluminum. This gives polyiso an advantage if you want to add vapor barrier properties that come with aluminum foil. Aluminum-faced polyiso, such as ECOMAXci® FR Air Barrier can be used as an air and vapor barrier when installed with properly sealed joints.


Fire Resistance

Polyiso performs well during high heat and fire testing. Rather than melting like other board insulations (XPS: Extruded Polystyrene), polyiso chars and does not spread flame.

Versatility

Polyiso is one of the most versatile insulations because it can be used all over the building envelope—including foundations, basement walls, exterior walls, masonry wall cavities, attics, and roofs.

Where to Buy 3” Polyiso Insulation

There are multiple supply chain venues where you can buy 3” polyiso insulation. Here are four options for getting enough polyiso for your project:

Home Improvement Stores

Some big box stores, like The Home Depot, carry a limited supply of polyiso board insulation. You can check their stock online and may even be able to place a bulk order from one of their home improvement stores. Beware though, the selection may be limited to 1”, 1-½”, and 2” and they may not carry 3” polyiso insulation. Buying from a home improvement store is also not ideal for large jobs, since the price will be higher than if you go through a contractor supply store.

Local Building Supply Store

You may have a local contractor supply store that carries 3” polyiso insulation. These stores include names such as ABC Supply, Richards Supply, and Gulfeagle Supply. Homeowners are usually able to purchase building products from these chains without a problem and they are likely to carry polyiso insulation. Even if the local stores don’t have 3” polyiso in stock, they should be able to order it in for your project.

Wholesale Suppliers

If you don’t have a local building supply store, you can also purchase 3” polyiso insulation online through wholesale suppliers like IDI Distributors, Insulation4US, or Service Partners. These wholesale insulation suppliers can ship polyiso insulation to locations throughout the U.S. with freight as low as $100. Be aware, some of the wholesale online suppliers may require that you are a contractor and/or placing a very large order.

Direct

Finally, for very large orders, you may be able to purchase 3” polyiso insulation directly from the manufacturer. Contact your preferred manufacturer, such as Rmax, to inquire about large orders. The advantage here is that you cut out the middleman and can save big on your building’s insulation.

Choosing the Right 3 Inch Polyiso Insulation

Before closing, we just want to touch on the fact that not all 3” polyiso insulation is created equally. As we mentioned above, the facer material for polyiso can add additional properties when used. Here are some Rmax polyiso products that are available in 3” thickness:

Get the Best with Rmax 3” Polyiso

Check out our videos to see what our customers have said about our ECOMAXci® polyiso system. If you’re ready to pick the right 3” polyiso insulation and order it for your project, contact our team of professionals today to get started!