MANAGEMENT-Fall 2024

Mastering Metal Deck Estimates

By Jason Kulvinskas

Metal decking installation is the most labor-intensive aspect of a steel erector’s scope, and numerous factors can directly impact labor costs. This makes an accurate installation estimate crucial for a successful steel erection bid.

The process begins with take-offs, where I quickly review the complete set of structural drawings. This provides an overview of the building’s shape, size, and complexity. I assess if the project has multiple buildings or multi-stories. We rely on Bluebeam Software to do take-offs, which has been an invaluable tool for our company.

After initial review, I identify critical details such as deck type, deck gage, attachment methods and patterns, elevations, and joist or beam spans. Below are some key considerations to take into account in order to make an accurate estimate.

Deck Specifications

There are several considerations with metal decking that influence labor costs. The deck type, gage, attachment methods and patterns are examples of factors that help develop your estimate. Specialty deck and heavier gages typically require more labor, which should be factored into your bid.

Deck Type: Most roof decks are 1.5” B Deck or 3” N Deck, while floor decks are typically 1.5”, 2” or 3” composite deck. Pricing standard deck is straightforward. However, specialty decks, especially those that are exposed and require uniform spacing, take more time to install.

Examples of specialty decks include Epic Super Wideck with a 9” Depth or Verco 3.5” Dovetail Deck. These often need to be installed one sheet at a time, sometimes requiring a crane to lift them in place due to their weight. Production rates on these non-standard decks can be 50-85% lower than for standard decks.

Deck Gage: Deck gage also affects production. While 18, 20, and 22 gage is common, 18 gage deck is heavier, and it can slow production. Less common 16 gage deck is very heavy making it difficult to break bundles, as the sheets tend to stick together due to their weight. This requires additional manpower to avoid overworking the crew and production reduction is significant.

Account for Attachment

Understanding the specified attachment methods and patterns is essential for accurate estimating. These details can significantly impact both material costs and labor requirements. Non-standard methods or patterns may increase project time and expense, but there is often room for negotiation with the Engineer of Record (EOR) to implement more efficient alternatives.

Attachment Method: Most plans specify puddle welds, with sidelaps secured by #10 Tek screws. Recently, there's a trend for large warehouses to require Hilti pins for attachment. While more expensive, they reduce labor costs due to faster installation, making them a recommended choice for such projects.

When #12 Tek 5 screws are specified, we often request a spec change with the EOR. Attaching with screws is more time-consuming to install than puddle welds or Hiti pins. If the deck is attached to purlins or thin joists, screws

are the better option, but for other cases, switching to an alternative can save money and expedite the schedule. For sidelaps, button punching or using the Verco Punchlok II tool doesn't typically increase labor. However, when welding sidelaps is required, labor costs rise significantly. Seam welds are more difficult and time consuming than putting in screws. If possible, we negotiate to switch from seam welds to sidelap screws. Occasionally, the EOR will allow the same quantity of sidelap attachments that was originally spec’d for welds to be used for screws. However, due to higher shear values derived from seam welds we usually put in several more screws to equal the original patterns. For instance, instead of three seam welds per span you may need 18 screws per span. In our experience, welding sidelaps on heavier deck, such as 18 gage, is a better application than on lighter gage decks (20/22 gage) as the welds tend to burn through the deck.

Attachment Patterns: Denser patterns require more material and labor. Standard patterns for floor decks include a 36/4 pattern with three to four sidelaps. Roof decks typically follow a 36/4 or 36/7 pattern for B-Deck, or a 24/4 or 32/5 pattern for 3” N Deck, with 4 to 9 sidelaps. However, we’ve encountered extreme patterns like 36/14 pattern with screws at 3” On Center. High pattern designs, often due to seismic requirements or over-engineering, can dramatically increase costs.

Design Differences

Estimating labor costs involves looking beyond square footage to consider the complexity of the building structure. Factors like beam spacing, building shape, elevation, roof pitch, and obstructions can all add time and costs to a project. Understanding these nuances not only aids accurate project planning but also ensures the safety and efficiency of the workforce.

Spans: The distance between joist/beams is important for several reasons. Closer spans require more attachments, while wider spans, such as those over 20 feet, raise safety concerns. Specialty decks with long spans pose risks, so ensuring at least two spans for safety is vital.

Building Shape: Square buildings require less cutting of deck and less labor, but when dealing with round or angled shapes, cutting and sorting the deck takes more time.

Elevations: Most buildings are between 30 to 65 feet tall. Boom lift rental cost for typical elevations up to 65’ are reasonable and the time for our crews to get to the work

area is not too long. Taller buildings, however, increase rental costs for larger boom lifts. In addition, production is impacted, as it takes longer for our workers to get to the work level. Higher elevations also tend to experience higher wind speeds, causing potential work delays.

Obstructions: Skylights, dunnage posts, screen-wall posts, safety davits, and threaded rods are all examples of roof design features that can dramatically slow production. Cutting around these obstacles takes extra time, so added labor should be factored into the estimate.

Drop-Downs: Certain buildings, like hospitals, may have multiple drop downs on the floors, typically for showers. This requires detailed work that can significantly impact margins if overlooked in the estimate.

Years ago, on a hospital project, I learned this one the heard way. I would not understand what was taking my crew so long to complete each floor. After a site visit, I saw first-hand that the added detail work for the drop downs was something I should have accounted for in my estimate. Overlooking this detail really hurt our margins.

Pitched Roofs: Pitched roofs are more challenging than flat roofs, and the steeper the pitch, the more time you should expect deck installation to take. A pitch of 3:12 or less is only slightly more time consuming than a flat surface, but as the pitch increases to 4:12 or more, the difficulty—and therefore the labor time—rises significantly. I consider 6:12 or steeper a difficult decking job. If a 5-person crew can complete 15,000 to 20,000 sq ft per day on a flat roof, that same crew may only be able to deck 300 to 600 sq ft per day on a 9:12 pitch roof. Another hard lesson learned—not knowing which direction the deck will be attached on pitched roofs. It is easier if the deck is laid horizontally at the bottom of the roof edge (east/west), so crews can work their way up the slope of the roof. It is far more difficult if the deck spans perpendicular from the bottom of the roof edge to the top ridge (north/south). This can be difficult to tell on structural drawings. In addition, very steep pitched roofs will require additional safety equipment for workers.

Small areas and separate buildings: Jobs often include smaller isolated areas, like guard houses or a penthouse, ranging from only 300 to 1,500 sq ft. These areas require higher square footage pricing due to the time required to set up and move equipment, which can take twice as long as it does to complete the actual deck installation.

Communication and Scheduling

Accurate estimating also requires considering the bigger picture, including the job’s location and timing. Environmental conditions—such as Arizona’s summer heat or low temps and snowfall in Maine during the winter—will likely mean production delays. The general contractor’s schedule expectations also impact workforce requirements and how much overtime will be needed to complete the job on time.

Location and schedule further influence hotel and equipment rental costs. For example, hotels in Florida during the winter can

be exorbitant, and equipment rental rates often rise during peak seasons.

Finally, knowing the building owner and structure’s intended purpose is vital. Facilities like data centers, aerospace manufacturing, or nuclear facilities come with unique safety requirements. Misjudging these can lead to costly mistakes, as I learned on a nuclear facility. Even though the building was not a difficult decking job, the unique work environment resulted in decreased margins. Initially, some costs were due to getting compliant on short notice, but others were beyond our control. The job frequently shut down for minor safety incidents experienced by other trades. It’s important to plan ahead for these delays in the same way you would for weather delays.

Ultimately, it’s better to lose a project by bidding correctly than to win a job that results in financial loss due overlooked details. By carefully considering the details of the project, you can ensure a more efficient and cost-effective project execution, potentially saving your client time and money while maintaining high-quality standards. •