Memorial Day Special!!!

All orders received between May 19 – 26 are eligible for a 10% discount!!!

Contact your sales rep today to get your quotes updated, mention promotion code: MEM17 on your Purchase Order!

If you have any questions, please feel free to give us a call at 281-469-8855 or email

We will be closed Monday May 29th in observance of Memorial Day!

What’s in a Name…Plate?

In the late 80’s early 90’s Curbco began to focus more and more on RTU curb adapters, we knew we needed to label our adapters, not only so we would be able to internally identify which adapter was going with which work order/job but also so that once the adapter arrived on the job site and was installed on the roof that the adapter could be identified easily in the future.

According to ASHRAE the average life span of an RTU is between 10-15 years, so in early 2002 contractors were on the roof and needed to replace an RTU that was already on top of one of our adapters, and what they found was…NOTHING!  The foil label that we had chosen to use as an identification tool was gone, nothing remained but a sticky mess.

So in about circa 2003 we began production of a galvanized metal name plate which is permanently welded onto our adapters.   On this name plate is our company name, Page Number (this is a unique identifier).

Our goal is to make the replacement of an existing RTU sitting on one of our adapters as easy as possible, and please, please don’t put an adapter on top of another adapter…I digress.

We have just created a new search tool that will allow a contractor and/or their favorite distributor to submit the “Page Number” to us so we can provide a quote and a submittal drawing needed to provide a replacement adapter

Announcing…The Adapter Bottom Search Tool!

Just follow the instructions and in less than 30 seconds we will have what we need to help you replace the failed RTU…FAST!

Get Those Submittal Drawings Checked!

If you’ve ordered a curb adapter design from Curbco (or anybody else, for the most part), then you’re already familiar with the submittal drawing, the drawing we create that shows precisely how the new curb adapter will fit in relation to the old or existing curb dimensions. This plan view diagram displays the outside diameter of the old or existing curb along the top and left sides, with a solid line outlining the adapter bottom and a slashed double line representing the new adapter top. Toward the right of the drawing you’ll see profiles showing how air will transition through the new RTU down through the curb adapter and the original curb. It will also show any degree over overhang that might extend beyond the original perimeter.

The submittal drawing shows exactly how the new adapter should work in conjunction with the curb and the RTU. Nothing is left to chance — except by the contractor who fails to check the submittal drawing against the real-life circumstances up on the actual roof. The problem is that no roof conforms to its perfect-perfect representation on the original blueprint. Anomalies develop. Holes get patched. Years of little modifications can manifest themselves as unanticipated projections or devices. The old part numbers may be unreadable or incorrectly listed. All these variables can cause unexpected problems at installation time — and that means lots of extra time, labor and expense.

Urge your contractor, in no uncertain terms, to take that submittal drawing up to the roof and compare the two with a fine-tooth comb, then report any variation, no matter how tiny. If you  can factor those changes into account now, you can save everyone a lot of grief later. Making a new drawing is easy — making a new curb adapter isn’t!

Roof Pitch Calculation Dos and Don’ts

Here at Curbco we’re happy to create curb adapters for sloped roofs as long as we have the data we need. (See two downloadable forms on our website, “Welded RTU Curbs” and “Calculating the Pitch of a Roof,” for a visual representation of this data.) In principle it’s straightforward enough. The contractors set the level on the roof slope, raise one end until the level reads true, measure the vertical difference distance between the end of the level and the roof surface, then divide that vertical measurement by however many feet the level is long. Voila, you’ve got your pitch.

But as simple as this procedure may sound, people can and do get it wrong, with disastrous results. If we build a curb adapter to the incorrect roof pitch, your RTU just won’t sit correctly. We then have to build an extension — an adapter for the adapter, so to speak — just to correct the imbalance. It’s a waste of time, money and labor, and it’s completely avoidable if we can have the right pitch measurements to begin with.

How do contractors get this measurement wrong? For one thing, they may assume their level is a certain length when in fact it isn’t. Ideally you’d want to use a one-foot level so you don’t have additional math to cope with on that side of the equation. But levels come in various sizes — two-foot, three-foot, four-foot, eight-foot, you name it. The contractors may also measure from the topside of the level to the roof surface, instead of from the bottom side. Or they may assume all the roof’s various slopes have the same pitch as the one they measured. Oops!


Make sure your contractors take the right steps to calculate roof slope. We’ll take it from there!

Field Survey Forms: Every Measurement Counts

When does a contractor need to fill out a field survey form? In a best-case scenario, we we can simply generate a submittal drawing that the contractor can then verify as good so we can move forward. But that’s only possible if we actually have the model numbers for the existing setup. If your contractor can’t read or find those model numbers, he needs to climb back onto the roof, tape measure in hand, and collect a precise set of measurements that we can use to fabricate the perfect curb adapters and equipment supports for the job.

As you can see from this sample, the Field Survey Form makes this process as error-proof as possible. The contractor picks whichever one of the six rooftop layouts comes closet to the real-life roof situation, listing it as the “orientation number.” From there he measures the various dimensions, categorized by the letters A through K, then records the sum of C through G under “Total.”

Now comes a critical question: Does that total number equal the number given for dimension A? If so, the contractor simply marks which openings correspond to the return and supply passages, and submits the successfully completed form. If not, he’s got to go back and measure each dimension again. Even a three-inch discrepancy will end up delivering a curb adapter that doesn’t fit properly. And if any part of the form is left blank, we just can’t work with it — and it’s back up to the roof with a tape measure again.

So if a customer tries to tell you, “Hey, we wrote down the dimensions, we’ll just send you those,” do yourself and the customer a favor by insisting on a completed, accurate field survey report. You’ll be a hero for looking after their best interests!

Energy Efficiency Can Help “Green” Businesses Get Greener

“Going green” is all the rage these days, and some businesses make it a priority not only to be environmentally responsible but to do business with others who feel the same way. But it’s not easy being green, especially for large commercial facilities that rely on older-model rooftop units. These units may still get the job done, more or less, but at what cost? A 30-year-old RTU lacks the microprocessor controls, fine tuning of air distribution, and the electronics to interface with modern energy management systems. Companies that aren’t taking advantages of these advances are almost certainly using way more energy than necessary. That’s bad for the environment, and bad for any business that wants to save money and maintain a reputation as a “green” company.

If your clients serve a metropolitan area that boasts a thriving environmental movement, or that rewards companies for fitting or refitting energy-efficient components, make sure they understand the considerable benefits of switching out their old RTU for a newer, more efficient one. Companies that value sustainability as part of their public image or corporate culture will be “walking the walk” to reduce their carbon footprint. The fact that they’ll also be saving money on their energy bill is icing on the cake — but it’s a pretty tasty icing!

Once your customers are ready to do their part for the environment, we’re ready to do our part to make it possible. Here at Curbco we have three decades of experience fashioning all kinds of curb adapters and their accessories. We support a “Who’s Who” of leading manufacturers (as you can see on our Home page), and our extensive database of pre-designed units enables us to help you bring today’s technology to yesterday’s buildings.

What Makes a Great Curb Adapter? pt. 3: Optimal Equipment Integration

Previously we mentioned the importance  of good airflow management. We achieve that by making absolutely sure the curb adapter design mates with the performance and structural specs of the RTU on one end and the supply and return holes that feed the building on the other end. But that’s only part of the process — we also have to make sure the curb adapter integrates with the equipment to accommodate other aspects of its design.

Engineers must make all kinds of considerations when designing the top of a curb for a specific RTU model. For instance, they may decide to add acoustical insulation to reduce noise or vibration. They may add moisture-resistant panels to protect metal surfaces from the natural condensation that occurs with equipment temperature changes. Or they may need to make room for an extra pipe, nipple or other object hanging down from the unit. A well-designed curb accommodates all of these little enhancements so that the equipment will integrate perfectly for years of trouble-free operation.

Unfortunately, a relatively inexperienced curb adapter company may not duplicate this original attention to detail in their adapter tops — they’re focused on making sure the supply and return ports line up and deliver the correct airflow. Yes, that’s important, but what about the soundproofing, the condensation protection, or those extra variables that the curb engineer had factored into the original design?

This is where 30 years of experience pays off. Our engineer, Van Smith, actually designed many of the systems currently in service. His first-hand experience with these devices helps him know where that insulating panel originally went (or needs to go), or where a pipe or nipple will need some extra room, ensuring that all the equipment integrates flawlessly. Experience isn’t just priceless — it can actually save a lot of money!

What Makes a Great Curb Adapter? pt. 2: Airflow Management

What happens if the motors, belts and other moving parts in your fans fail? If a faulty RTU adaptor design was to blame, would the warranty coverage become invalid, leaving your customers to pay top dollar for repairs? And even if the fan does keep working, how much extra will they pay in maintenance costs and energy bills to run the thing at full power all the time? Your commercial clients and contractors need to understand the importance of proper airflow management — the kind that only a perfectly integrated curb adapter can provide.

External static pressure is a big factor. This is the air pressure exerted by the walls of the curb adapter’s inner surfaces that the fan must overcome to push or pull the air in the right direction at a sufficient CFM (cubic feet per minute). Negative static pressure pulls air, while positive static pressure pushes it. So you can guess what happens if your curb adapter doesn’t match up with your curb and/or rooftop unit, or employs the wrong design for optimal efficiency. The external static pressure may turn out to be stronger than the designed flow, forcing you to run your equipment harder to get decent results.

An efficient curb adapter design takes friction, shaft diameter, fan power and velocity, air density, and other factors into account. The less effort required to push air at a given CFM, the less work the parts have to do and the longer they will last — without blowing the warranty coverage. And the ability to run at lower power levels is its own reward when it’s time to pay the utility bills. At Curbco we determine the precise airflow metric for a particular system, and then create a curb adapter designed to perform accordingly. That’s smart airflow management!

What Makes a Great Curb Adapter? pt.1 of 3: Structural Integrity

Are some curb adapters stronger than others? Well, sure. The structural integrity of a curb adapter depends on the gauge and quality of the steel, the care taken to protect against  corrosion, and of course smart design.

Our industry uses G90 galvanized steel as a standard material for curb adapters. The heavier or more massive the material, the stronger it’s going to be. Depending on the local climate, a rooftop curb adapter may face winds, rain, ice, hail, dust storms, or even earthquakes. Too light a gauge may also buckle under the weight of an exceptionally heavy unit, so we insist on using the correct weight of steel for the job. Better to spend a little more on stronger materials than be forced to replace a weak curb adapter later on.

As for the threat of corrosion from years of exposure to weather, G90 will hold up to moisture and air pollutants just fine. We also coat our welds with a galvanized paint, heavy on the zinc, to protect them from oxidizing. Zinc coatings actually react with oxygen, moisture and carbon dioxide in the air to form a tough, impermeable layer of zinc carbonate — a second skin that the elements can’t eat into any further.

The shape of a curb adapter — the arrangement of ends and folds that give it the desired three-dimensional form — also contributes to structural integrity. Think of a cardboard box — it’s just a floppy piece of material until you turn those tabs in and create something that holds itself together. We know how to fold sheet metal to get the maximum amount of strength out of it. That’s why you can trust Curbco to fashion a curb adapter that will stand the test of time.

Summertime: The Season for Curb Adapters

Ah, summer. Who doesn’t love the bright summer sun, the warmth and the late sunsets summertime brings? Actually, any facilities manager could tell you the answer to that one. Unless you live in Antarctica, summer means hotter temperatures for more hours of the day — and that means higher energy bills. Could this be the ideal time for your customers to take a good, hard look at the efficiency and future lifespan of their rooftop packaged units? You bet!


The last thing any business needs is to have their HVAC system pack up on them during the dog days of summer. Urge your customers and prospects to start thinking about how many years their RTU may (or may not) have left. Better to replace an old unit before it fails than after the fact! Even if they anticipate several more years of functionality from their equipment, what is what equipment’s EER (energy efficiency rating)? A lot has changed over the last couple of decades; in 1994, for instance, only 14 percent of commercial models had an EER of 10.4 or above, but by 2007 that number was up to 65 percent, according to ENERGY STAR. At at no time of year does that increased efficiency matter more than summertime!


Of course, a commercial facility that decides to install a new RTU during the heat of summer will be in a hurry to get the new unit up and running as quickly as possible, but they also need and expect quality work. Curbco scores on both counts. We run two shifts all year round and rely on a huge knowledge bank of design specifications, so we can turn out the curb adapters and supports you need within two to three days. Trust Curbco for cool ways to cope with hot days.