Hidden Materials: The Cost of “Squirrel Nests” in Maintenance

Walk through almost any industrial facility and you may find spare parts tucked away in toolboxes, cabinets, desks, or maintenance shops. These hidden stockpiles—sometimes called “squirrel nests”—usually start with good intentions.

A technician needs a critical part, doesn't trust that it will be available next time, and decides to keep an extra one nearby.

The problem? Those materials belong to the organization, and when they disappear from the formal inventory system, they can create unnecessary costs, inaccurate inventory records, and maintenance delays.

Why Do Maintenance Teams Hoard Spare Parts?

Material hoarding is often a symptom of a larger problem: lack of confidence in the MRO storeroom.

If technicians repeatedly experience stockouts, inaccurate inventory counts, or difficulty getting the parts they need, they may begin creating their own unofficial inventory.

Over time, these small stashes can multiply across a facility.

The organization may purchase additional parts because the CMMS or EAM says none are available—even though the same materials are sitting unused somewhere else in the plant.

The Hidden Cost of Hidden Materials

Squirrel nests can create more than an inventory problem. They can tie up working capital and make it difficult to understand what the organization actually owns.

Hidden materials can contribute to:

• Duplicate purchases
• Excess inventory
• Inaccurate inventory counts
• Parts becoming obsolete or deteriorating
• Difficulty locating materials
• Poor purchasing decisions
• Increased maintenance costs

A part that can't be found when it's needed provides little value, even if the organization technically owns it.

Build Trust in the MRO Storeroom

Simply telling technicians to stop hoarding parts won't solve the underlying problem.

Organizations need to understand why the squirrel nests formed in the first place.

If employees don't trust the storeroom, the answer is to improve the storeroom.

Accurate inventory records, appropriate Min/Max Inventory Levels, consistent receiving and issuing practices, and reliable material availability can give technicians greater confidence that the parts they need will be there when they need them.

A well-managed MRO storeroom should support maintenance execution—not encourage employees to build their own backup inventory.

Three Ways to Eliminate Hidden Materials

Organizations can start by focusing on three areas:

1. Improve storeroom reliability.
Make it easier for technicians to trust that required parts will be available and accurately represented in inventory.

2. Improve inventory tracking.
Use EAM and CMMS processes to accurately record where materials are stored, when they're issued, and how they're consumed.

3. Educate the workforce.
Help employees understand that hoarding parts may solve an immediate individual problem while creating larger inventory and cost problems for the organization.

The goal shouldn't be to blame technicians for squirrel nests. It's to create a materials-management process they no longer feel the need to work around.

Better Inventory Supports Better Maintenance

Effective spare-parts management is ultimately about having the right material, in the right quantity, in the right place, at the right time.

When technicians trust the storeroom and inventory records reflect what is actually available, organizations can reduce unnecessary purchases, improve material availability, and make better maintenance decisions.

Watch Quarantined – Day 8 to learn more about hidden materials, squirrel nests, and how better MRO inventory management can help control maintenance costs.