Enclosures: Wear, Tear, and Fiberglass Repair

hot box next to stcIn a few locations in the United States, including North Carolina and Washington state, fiberglass enclosures are commonly installed for backflow assemblies. As in most things we all deal with, once something is accepted, the status quo is difficult to change. That’s the case with fiberglass enclosures. What we feel is the better product for the application, an aluminum enclosure, is typically not considered in these specific markets simply because of the status quo. Perhaps these markets should start thinking about more factors than the status quo when making a decision about equipment protection. Here are a few for them to consider regarding the long term costs of fiberglass enclosures vs aluminum enclosures.


Fiberglass - We all have some experience with the adverse effect of the sun on materials. In the case of fiberglass, prolonged exposure to direct sunlight can have an adverse effect and could result in fiber bloom. If the fiberglass enclosure is not manufactured with a UV inhibitor, the UV rays of the sun will break down and weaken the fiberglass over time. If you are considering a fiberglass enclosure or fiberglass shelter, be sure to ask the manufacturer for details concerning the UV inhibitor. You don't want to be worrying about whether the enclosure perform the intended performance in 20 years.

Aluminum - Sunlight does not impact the structural properties of the aluminum used to manufacture aluminum backflow enclosures or aluminum equipment shelters. This means that 50 years from now the aluminum should be in excellent condition serving its purpose providing protection for the interior equipment. 

tester working in an aluminum enclosureAccess

Fiberglass - There are two main designs for fiberglass enclosures. One is the lift-top style where the enclosure either looks like a clam shell or is small enough that the entire box is on a hinge which can be lifted to reveal the equipment beneath it. This would provide sufficient access to the equipment for maintenance if the enclosure is small. For larger equipment including flange-sized and larger backflow preventers, you'll see fiberglass enclosures with hinged doors and hinged roofs. Once again, this design would work well enough for most maintenance, but what if the equipment needs to be lifted out and replaced? From what we've seen in the market, fiberglass enclosures do not typically have a removable roof or any way to easily replace the equipment.

Aluminum - Not all aluminum manufacturers follow the same practice, but Safe-T-Cover uses a modular design. This means that you can choose to add removable or hinged access panels and doors nearly anywhere on the enclosure. This allows maintenance personnel easy access to the equipment and provides ample room to get in and out of larger enclosures. Safe-T-Cover in particular also ensures that each enclosure has a roof that can be easily removed so that the equipment can be lifted from the enclosure. If you are looking for a pump cover, this is especially important to keep in mind.


weed_eater_cuts_through_fiberglass_enclosuresFiberglass - First of all, the weed eater is a foe to the fiberglass backflow cover. Here’s a picture of what happens when the weed eater comes in contact over time with the backflow cover.The location of this installation is a drug store in western North Carolina.This enclosure will not provide the freeze protection the building owner paid for. Unfortunately, we've seen this type of damage again and again. There is no good reason for it to continue. Additionally, fiberglass is prone to shatter and fracture with a hard blow. If a delivery truck backs into your cover, or a tree limb falls on it, you will likely need to replace the whole thing.

Aluminum - If a car or tree damages an aluminum enclosure, you may still need to replace the entire enclosure depending on the extent of the damage. However, because of the panel design and because aluminum will crumple and bend rather than shatter, you may get away with just repairing the enclosure rather than ordering an entirely new one.


damaged_Safe-T-Cover_but_not_equipmentFiberglass - Some fiberglass shelters are shipped assembled and put in place with a crane. This indicates the repair may not be as fast and could be more costly as it's likely the entire shelter would need to be replaced even if only part of it is damaged. A field repair may be the quickest solution to the problem, however most fiberglass repair must be done when temperatures are at least 65 degrees and moisture will cause the repair to fail. In the right conditions, you can repair fiberglass with a patch, acetone, sandpaper, and a dremel. Then you'll need to use resin, hardener, and apply new gel coat as well. Here are fiberglass repair instructions from a fiberglass shelter manufacturer.

Aluminum - Because of our panel design, Safe-T-Cover's aluminum enclosures can replace a single damaged panel or selected panels. At Safe-T-Cover, our standard line of enclosures are manufactured using a few panel sizes, meaning we typically have each type in stock ready to be shipped. This is a quick and inexpensive repair that can done at any time during the year which means your equipment is fully protected again in a short period of time. If the aluminum shelter is a popular standard model, the manufacturer might be able to ship a complete enclosure the next day if needed.


For small diameter sizes only, fiberglass enclosures will typically cost a bit less. That is, if you only consider the up front costs rather than the costs for the life of the equipment. Repairing fiberglass enclosures is more difficult and expensive than ordering a new panel to replace a damaged one on an aluminum enclosure. Additionally, for flange sized installations, in North Carolina especially, an aluminum backflow enclosure costs the same and sometimes even less than a fiberglass backflow enclosure. As a purchaser of an enclosure, you want to buy the right one. After all, the enclosure is probably covering an important and expensive piece of equipment. You want it to deliver on its intended purpose and be as trouble free as possible. Keep these factors in mind as you speak with manufacturers to help you to make an informed decision.

heated enclosures available in four colors at base price

Related Posts

What Are the Size Limits for a Custom Enclosure?

From the Field: The Benefits of Genuine California Redwood Bracing in Safe-T-Cover Enclosures

Winterize Your Backflow In Eight Steps (or One)

Aluminum Enclosures and Concrete Pads: Total Security and Confidence

Choosing a Pump Cover: Clamshell Fiberglass vs. Aluminum Pump Covers

LEEDing the Way: Enclosures and How LEED Can Benefit You

Built to Prevent Enclosure Color Fading: The Science of Safe-T-Cover

Low Price, High Cost: Fiberglass Enclosures Are Built to Fail

Everything But the Bow: Custom Wrapped Graphic Solutions for Enclosures

Lighting and Your Aluminum Enclosure

Beyond Aluminum Enclosures: Our Commitment to Corporate Responsibility

Protection from Sound and Fury: Safe-T-Cover Enclosures and Noise Dampening

From the Field: Tips for Safe-T-Cover Enclosures and Protective PVC Coating

Aluminum Pump Enclosures vs. Pump Packages

Standing Out By Blending In: Safe-T-Cover Enclosures Made to Order

Introducing the MUNI-LOK from Safe-T-Cover

Air Cooler Enclosure Solves End-User Problem

Installing Fire Dept Connection & Backflow Prevention Valve for Safety

Follow This Custom Enclosure Design Checklist To Protect Your Equipment

Selecting the Right Heater for a Backflow Cover

Finding The Right Style Enclosure For A Small Pump Package

How To Keep Your Pump Cover Cool In Warm Weather

5 Ways Panel Design Equipment Covers Offer Superior Flexibility


Project Engineer vs. Maintenance - A Valve Cover & Pump Cover Tug-of-War

Infographic: Backflow Preventer Design Done Right

How To Size A Custom Backflow Enclosure

How Do You Hide A Backflow Enclosure?

Why You Need An Irrigation Pump Cover

What Features Should Every Pump Cover Have?

How To Ensure Your Insulated Backflow Enclosure Stays Warm

The Best Way to Cover Your Booster Pump is With a Pump Enclosure

The Last Backflow Enclosure Aesthetics Guide You'll Ever Need

Introducing the Digital Binder: Submittals, Top Blogs, Drawings and More

When You Should Use Backflow Theft Prevention Cages

Aluminum Pump Enclosures vs Pump Buildings

Why You Should Install Multiple Backflows in One Aluminum Enclosure


What Made Fiberglass Backflow Enclosures So Popular?

Can Wooden Storage Sheds Work as Waterworks Equipment Enclosures?

Backflows Need Thermally Insulated Enclosures (& They Don't have to Be Ugly)

Fiberglass Shelters vs Aluminum Shelters - What's the Life Cycle Cost?

Can you have a Fire Department Connection on an Enclosure? Yes! It's a Safe FDC Location

How to Make Aesthetically Pleasing Aluminum Shelters? Just Add Color

Which Do You Need - A Cage or Enclosure For A Backflow Preventer?

Enclosures Help With Loud Equipment and Pump Insulation - Keep Your Sanity

The Enclosure Heater Guide For Industrial Equipment

When Is A Backflow Enclosure Cage No Longer Enough?

How Much Do Custom Aluminum Enclosures Cost?

Case Study: Large Pump Covers and Air Conditioning Pump Enclosures

How to design & Buy a Pump Enclosure

Get the free, editable checklist.



Have a question about a backflow preventer enclosure?
Click the contact us button below and one of our experts will be able to help with your specific enclosure needs.