How Walk-in Panels Create an Airtight Seal

stacked walk-in panels
Modular panels are equipped with cam locks and double barrel panel gaskets.

Air infiltration, or lack thereof, plays a major role in an efficient walk-in cooler or freezer. Walk-ins are manufactured to be air-tight because any cold air that escapes will lower efficiency and any warm air that enters can cause condensation and icing problems. Air and moisture infiltration can damage panel insulation, causing it to lose R-value and reduce the life of the walk-in. It seems like a walk-in constructed of numerous separate panels would be prone to air leakage, but this isn’t the case. So how do manufacturers of walk-ins create an airtight seal between panels?

gray screeding
Screed for the base of walk-in panels

Manufactures have different methods of sealing panels, but at U.S. Cooler, we use precision-cut tongue & groove insulation between two metal skins (of galvalume or stainless steel), cam locks and panel gaskets. The interlocking design of our panels ensure they fit together like puzzle pieces and are held tightly in place by aligning and tightening cam lock mechanisms. Double-barrel compression gaskets line the inside and outside of each panel. When the panels are locked into place with a cam wrench, the gaskets seal against each other and create an air and moisture barrier. Walk-in coolers without an insulated floor are inserted into a vinyl channel (screed) to prevent air from entering when mounted on concrete.

Polyurethane: One More Option For Your Walk-in

It’s Your Choice.

U.S. Cooler is one of the few manufacturers who can now offer both extruded polystyrene and foamed-in-place polyurethane insulation for walk-in coolers and freezers. As any good business does, we are always seeking new ways to serve our customers better and stay competitive in the marketplace. One of these ways is to provide additional services to our customers and dealers. Recently, we have added foamed-in-place polyurethane to our product offering. Previously, U.S. Cooler only offered extruded polystyrene insulation.

insulation polyurethane polystyrene

U.S. Cooler’s new polyurethane panels are foamed-in-place filled with class 1 polyurethane foam made from CFC and HFC free materials. By utilizing state of the art horizontal presses and technology, panels lie flat during the foaming process which reduces voids in the insulation. The panels’ structural tongue and groove, cam-locking system provides an air-tight seal between the panels restricting air infiltration into the insulation core.

U.S. Cooler’s polyurethane walk-in products are made with the same exceptional quality and performance construction that has proven successful in the industry.  By adding a new product line to our manufacturing capabilities our product excellence has not changed.  U.S. Cooler still provides the same premium, high-quality products and customer service we have been offering for over 25 years. Every walk-in is pre-assembled in our manufacturing facility before shipment to ensure precise quality control and ease of assembly in the field. All our panels come with our standard 10 year warranty.

Polystyrene Walk-in Brochure

Polyurethane Walk-in Brochure

Do Walk-in Cooler & Freezer Walls Wear Out?

Hi there,

Do walk-in cooler walls wear out over time?

I build restaurants and we are renovating a restaurant we built 17 years ago.  A supplier is recommending we replace the walk-in box, because they “break down”. I find that hard to believe. Could you please give me your opinion?


– Len Chaston


On the surface, your walk-in box probably has a few scratches, dents and slightly worn metal but overall it appears serviceable and is likely structurally sound. However, the insulation inside the panel can take a much more severe beating over the years than the exterior. The insulation has to deal with huge temperature differentials between the inside and outside of your box. Depending on the material used to insulate your box it could have absorbed a good deal of moisture, which degrades the thermal resistance of your insulation. Your old walk-in was also not built to meet modern efficiency and safety requirements and it could even contain a large amount of wood (which is a poor and water permeable insulator). If you have a walk-in freezer, one indication of trouble is ice buildup on the inside of the box. This is a sign that water vapor has been able to infiltrate the insulation.

At 17 years old, the cost of running the walk-in for several years as well as the added load and wear on your refrigeration unit will far overshadow the cost of purchasing a new walk-in unit. If you do decide to opt for a new walk-in, I want you to take a look at the inside of the panels when your old unit is disassembled. A panel that is now leaking all over the floor was no longer doing the job it was intended to.

leaking walk-in panel
Ice buildup in a walk-in panel

False Information about Extruded Polystyrene

Recently, there has been a document circulating in the industry that has a lot of misinformation concerning the use of extruded polystyrene insulation and its compliance with the Energy Independence Security Act of 2007.

We normally ignore incorrect information that is generated with the sole purpose of discrediting a competitor but the severity of this document begs to be clarified.

The document can be found by clicking the pdf icon.pdf icon

extruded polystyrene insulation
Extruded Polystyrene Panels

First, there are presently two types of foam insulations being used in the manufacture of walk-in coolers and freezers in the United States.  These insulations are Extruded Polystyrene and Foamed –in –Place Polyurethane insulation.  Many companies in North America have the ability to use both types of these insulations.  Both insulations have benefits that can be used to provide a quality walk-in cooler or freezer. Companies that use both types of insulation can apply each of these insulations in parts of a walk-in that they perform best and therefore bring the best designed quality walk-in cooler or freezer to the marketplace.  Some companies do not have the capability and therefore turn to attacking the insulations they do not have the ability to use with misleading information to compensate for this deficiency.   This situation seems to be one of them.  There are six points that need to be addressed.

Zero Ozone-Depleting FOAMULAR Extruded Polystyrene Insulation

Toledo, Ohio – Owens Corning (NYSE: OC), a global leader in building materials and energy efficiency solutions, today announced it has started manufacturing zero ozone-depleting FOAMULAR® Extruded Polystyrene (XPS) rigid foam insulation. The new blowing agent technology developed by Owens Corning meets the requirements of the Montreal Protocol which requires the phase-out of the hydrochloro-fluorocarbon (HCFC) 142b, an ozone-depleting compound, by January 1, 2010.

Owens Corning’s new Gresham plant is the first facility in the Western U.S. to meet the requirements of the Montreal Protocol and expands the company’s XPS foam production capabilities. The company also has converted its Rockford, Ill., insulation plant to use the new blowing agent, and all FOAMULAR products will meet the requirements of the conversion deadline.

owens corning insulation plant

“High performance homes and buildings are an ever-growing segment of the construction industry, and

Debunking the Myth of Laminated Panels

Myth: “Laminated” or “Slab” panels are inferior to urethane because they are glued to the skins to hold the panel together. Therefore, these types of panels are not considered as durable and are thought to come loose within a short period of time.

Truth: For over 40 years walk-ins have been manufactured by either gluing insulation to metal skins (laminated) or pouring urethane (foamed-in-place) between two metal skins.  Contrary to most beliefs, both systems provide equal performance in adhesion if applied correctly.  This is important because in walk-ins the structural strength of the unit is dependent on this adhesion performance.  When metal skins are glued or foamed to insulation a composite panel is created.  This created panel performs much like a steel I-beam. I-beams by design are very strong for their weight and are used in building structures that need a lot of strength without the weight, such as skyscrapers. A steel I-beam is two flanges of steel connected and separated by a center steel web.  In a walk-in panel, the two flanges are light gauge metal skins and the web is the foam insulation.  All I-beams lose their strength if the flanges separate from the web. If the I-beams separate, skyscrapers would collapse. This is similar to walk-ins that could fail if the skins separate from the foam insulation.

A Matter of Insulation: Acquisition vs. Lifetime Savings

Your cold storage equipment may be one of the most important choices you make. A significant amount of costs are associated with your walk-in. Before you purchase, make sure you consider the entire lifecycle of the walk-in instead of just the acquisition price.

The two main elements that effect energy and cost savings while running a walk-in are the refrigeration and insulation.  To get the optimal results from your refrigeration it must be sized correctly taking in consideration the size of box, if it is a cooler or freezer, and what will be stored inside. (There are many other factors that are considered when sizing refrigeration.) Insulation is the key to energy savings because it is responsible for holding the cool temperature in the box so the refrigeration does not have to work overtime. Insulation quality is measured by R-value; the resistance to heat flow through an object. Since EISA was implemented January 1, 2009, all walk-in manufactures are required to have an R-value of R-25 for coolers and R-32 for freezers. Now that all manufacturers follow the same requirements, the performance of the insulation is what differentiates the walk-in.

The two common types of insulation used are polyurethane and extruded polystyrene.  Each type of insulation brings with it strengths and weaknesses that must be evaluated for each individual application.

Insulation Strength Weakness
Extruded Polystyrene Starts with a high R-value. Smaller cell structure. Resists moisture absorption. Closed cell structure. Out gases some. Over time, R-value decreases minimally.
Polyurethane Starts with a high R-value.  Closed cell structure. Out gases more. Over time, R-value decreases steadily. Is susceptible to moisture infiltration.

U.S. Cooler uses both insulations. Through experience and research, U.S. Cooler believes extruded polystyrene is the best insulation for the walls, ceiling, and floors of coolers and freezers. Polyurethane is better to insulate the doors of their walk-ins. According to a study performed by the U.S. Corps of Engineers, they found that over a five year period extruded polystyrene retains 75% of its R-value while polyurethane retains 25%.¹  This is one reason why U.S. Cooler believes extruded polystyrene provides the most value and the best option for walk-in insulation.

Polyurethane & Extruded Polystyrene walk-in insulation
Polyurethane & Extruded Polystyrene