Mezzanine Deck Types: Open Bar Grating

Painted 19W4 open bar grating on an observation catwalk

Open bar grating deck surface on an observation platform.

 

Let’s continue our exploration into the different types of decking used on our mezzanines.  Last time we talked about corrugated roof deck with resindek.  We mentioned that as a wood composite material it can swell if soaked, so it is not the ideal deck type for wet environments.  Today we’re going to talk about one deck type that excels in wet environments:  open bar grating.

The typical grating that we use is a 19W4 bar grating.   It’s made by taking steel bearing bars placed 1-3/16” on center and joining them together by welding wire rod cross beams perpendicular to the bearing bars every 4” creating an open grid.  The grating typically has either a painted or galvanized finish depending on the application.

Galvanized serrated 19W4 open bar grating on a mezzanine deck

Serrated and galvanized open bar grating on a landing bound for the outdoors.

 

Galvanized and serrated open bar grating is an ideal deck solution for outdoor applications.Open bar grating has many advantages as a decking material.  It is very strong and durable, and the grated surface provides excellent traction.  For particularly slick locations, such as oil factories or outdoors in icy environments, we offer a serrated version for even better grip.  As an open decking surface it easily allows water, air, and light to pass through the system.  This is why it is a particularly popular decking material for outdoor applications.

There is one common misconception about the open bar grating that I would like to note though.  We are often asked to put open bar grating in sprinkled environments, with the customer thinking that they will not need to add sprinkler lines below the platform.  Unfortunately this is not the case.  The decking and framing of the mezzanine system occlude the area below enough (even before factoring in the materials on top of the platform) that your fire inspector will still require you to sprinkle below the deck if it is sprinkled above.

Oddly enough, open bar grating’s strengths are also its weaknesses.  As a fabricated steel material, it is significantly more expensive than the resindek.  The grated surface makes it extremely difficult to roll pallets and such around on top without adding something like a layer of plywood in order to provide it with a smooth surface to roll across.  And as an open, porous material it allows things to flow through it, such as fingers, heels, dropped hardware (i.e. nuts, bolts, screws), or spilled material.

Outdoor Stairs for a Construction Trailer

How to get safe permanent access to a construction trailer

Wooden construction trailer stairs

Temporary wooden construction trailer stairs

Job site construction trailers are used all over. Some are temporarily placed in location and then relocated, and some are permanently stationed. The construction trailers can house offices, tools, machinery, electrical controls and more. Oftentimes, job site trailers will have temporary wooden stairs affixed, like the above photo. But what do you do when the construction trailer is actually in a permanent or semi-permanent location?

assembled metal stairs for construction trailer

Shop assembled job site stairs

We often get calls to fabricate replacement construction trailer stairs to replace temporary wooden steps. The stairs below were used with job site trailer that housed electrical control modules and needed a safe OSHA compliant means of access from two sides.

removable handrail on metal stairs

Close-up of removable handrail option

As the construction trailer had some large control modules inside, we supplied stair landings with handrails that can be unbolted, to allow ample access should any module need to be replaced. The stair railings were welded to the stair stringer to maintain a stiff, wobble-free grabbing surface.   In an effort to help keep costs down on the project, the stairs were supplied with two support columns instead of four. This was achieved by bolting the platform edge of the landing to the existing structure, allowing for less steel to be used and a smaller concrete pad to be poured.

stair landing with grating for snow

Bar grating decking allows dirt and snow to fall through – allowing for a safe, clear walking surface

Construction trailers are generally located outside in work zones, oftentimes lacking paved access to the doors. With that in mind, the stair treads and stair landing surfaces are most commonly constructed from bar grating. Bar grating is inherently self-cleaning; mud, dirt, rain and snow fall through the treads keeping them cleaner and safer to step on. The landing also has toe kick around the non-entry and exit locations. The 4” high toe guard stops tools and other items from being kicked off the landing. It also serves to stop a slipping foot from falling off the landing, potentially preventing a serious injury and employee downtime.

fully assembled construction trailer stair with galvanized finish for corrosion  protection

Construction trailer stair with a galvanized finish for superior corrosion resistance

As for finish, hot dipped galvanized is one of the best, cost effective finishes to use when the stairs will be exposed to the elements. No chipping, peeling or blistering of the coating will happen. In fact, when the hot dipped galvanized surface is scraped to bare steel, it will ‘self-heal’. The zinc rich galvanized surfaces to the sides of the bare metal will sacrifice themselves to protect the base steel until all of the surrounding zinc is consumed. Hot dipped galvanizing also coats 100% of the structure because it is immersed in the zinc solution, as opposed to being painted on, which can miss hard to reach areas.

Overview of the prefabricated mezzanine installation

By Derick

Front topside view of the completed parts storage mezzanine

Front topside view of the completed parts storage mezzanine

We’re often asked by customers if they’re able to install their mezzanine order on their own. The following series of pictures were sent to us from a customer who did just that, and should provide you with a general idea of what a mezzanine installation entails.

First, a little bit about the mezzanine. The customer was a metal welding and fabrication shop in Iowa and they were looking to move their parts storage up above the production floor. They wanted to provide their own staircase, but contacted us to design and provide them with a 46’ x 24’ mezzanine. Because this was going above their production area, they wanted to maintain at least a 10’ clearance height and to minimize the number of columns below the mezzanine deck. The mezzanine clear spanned the 24’ and broke the 46’ span into two 23’ nominal bays using a beam and c-section framing system. This left the customer plenty of space to maneuver around and work below. The deck was designed to accommodate both the point loads from their single rows of shelving as well as 125 psf distributed live load to accommodate 4’x4’ pallets up to 2000 pounds each.   With the mezzanine situated in the corner of their building, we provided industrial use two rail handrail with a 4” kick plate on the two exposed sides, as well as along the opening for the customer’s staircase per IBC code. The decking on the other two sides was extended beyond the framing to the existing walls in order to utilize deck space and eliminate the need for additional handrails. The customer added additional resindek to their girders in order to further close off the walls and protect their insulation.

Attaching the primary framing members to the columns

Attaching the primary framing members to the columns

Now for the installation of a prefabricated mezzanine, we would recommend a three man crew. You will want a fork lift on hand, and a scissor lift if possible. As everything is typically bolted together or fastened with a self-tapping screw, there is very little in the way of specialized equipment required.

Starting in the back corner and working forward, you’ll begin by positioning your columns and bolting in the primary framing members. Use the forklift to position the beams and hold them in place while you connect them as the beams can be quite heavy. A spud bar will come in handy to align your bolt holes. You will need to reach inside the square tube columns to tighten the bolts.

Connecting the secondary framing members

Connecting the secondary framing members

After the primary framing members have all been attached, your next task is to bolt the secondary framing members to the primary framing members. After all the framing is connected and tightened down, it’s time to anchor the columns to your floor with the provided concrete wedge anchors.

 

Installing the corrugated roof deck on the mezzanine

Installing the corrugated roof deck on the mezzanine

Next you will install the kick plate and decking to your platform. In this example we used a corrugated roof deck for the structural component and covered it with resindek. This was done to provide the customer with a cost effective and smooth surface to work on. The kick plate is an angle that goes between the roof deck and your primary framing members. This closes off the platform so you cannot see down the corrugation of the roof deck from the sides. It also protects workers below the structure from material/tools, etc. that could roll or be kicked off the top level. The roof deck sub floor is fastened down to the framing members below using the provided self-tapping screws at every valley. You’ll then need to install the deck surface and secure it to the sub floor. The tek screws for the resindek are provided in a ribbon for use with a stand-up screw gun in order to speed up the installation process, as each 4’x8’ sheet of resindek takes 20 screws to properly fasten.

Installed unfinished resindek on the completed parts storage mezzanine

Installed unfinished resindek on the completed parts storage mezzanine

We’re almost finished now. Our railing is typically mounted on the face of the mezzanine with a post that will need to be bolted on every eight feet at maximum. The railing typically ships in 21’ long pipes that are cut in the field to the appropriate lengths. The cut handrails are then connected together with the provided splices and pipe elbows, and are fastened to the saddle brackets of the posts. You will need to install the splice clips for the kick plate at every seam to establish a continuous appearance.

Underside of beam and c-section mezzanine with surface mounted lighting attached to the roof deck

Underside of beam and c-section mezzanine with surface mounted lighting attached to the roof deck

Generally you would still need to bolt the treads to the stringers and finish off the handrail for the staircase, but in this case the customer was going to fabricate their own stair.

While this has been just a general overview, your mezzanine would ship with a very detailed set of assembly drawings and instructions that would go into much greater detail on the installation. This customer was pleased with the ease everything went together and the quality of the platform.

Adding a Platform Above an Existing Walled Off Space

View from the side of the platform showing the cantilevered edge to carry the platform over the existing wall

View from the side of the platform showing the cantilevered edge to carry the platform over the existing wall

By Derick

We were contacted by a customer who had an existing walled off area on their floor that they were using for long-term storage.  They were running out of room and asked us to build a platform above it, as well as to span over another adjacent room to expand their storage space.

Overall, the platform was to be 42’ wide x 12’ deep in order to stretch over both rooms.  We needed to maintain a 10’ clearance height under the platform to clear their existing walls, and the deck was designed for light storage at 125 lbs per square foot live load, which would accommodate their light shelving storage as well potential future pallet storage for pallets up to 4’x4’ and weighing up to 2000 lbs.

View from underneath the platform with the columns and OSHA stairs dropping into an existing walled off area

View from underneath the platform with the columns and OSHA stairs dropping into an existing walled off area

We had to be very careful with the positioning of our columns on this project because the customer didn’t want anything in front of the building that might interfere with their aisle way. We set the mezzanine columns back inside the existing room and extended our deck to the front of the building.  Likewise, because the customer wanted to keep the stairs inside the footprint of the platform, the customer requested that we use an OSHA staircase as opposed to an IBC staircase. An IBC stair has a more gradual angle of decent with a 7” maximum rise for every 11” tread and requires an 11” handrail extension at the bottom (or in some locations, such as here in Ohio, 23”) An OSHA staircase with generally has around an 8” rise and 9” treads and does not require handrail extensions at the top and bottom.  The IBC staircase would not leave them with sufficient room at the bottom between the handrail extensions and the columns to access the stairs, so the decision to go with OSHA freed up some space for them.

Top of deck view of the platform with unfinished Resindek field cut around customer’s existing ductwork and a 6’ bi-parting swing gate

Top of deck view of the platform with unfinished Resindek field cut around customer’s existing ductwork and a 6’ bi-parting swing gate

For the decking we used a corrugated roof deck (painted reflective white) and skinned it with an unfinished ¾” Resindek LD.  This gave the customer a nice smooth deck surface up top and was significantly less expensive than a metal deck. The framing was held off the main walls of the building by about 6”in order to clear the base plates centered under the columns, to clear some small ducts and an existing building column the customer had running up their building’s primary walls, as well providing the installers with enough room to bolt the framing together. The decking was then run beyond the framing back to the customer’s walls and trimmed in the field by the installers to go around the customer’s existing building column and ductwork.

Top of deck view showing internal OSHA staircase and unfinished Resindek field cut around customer’s existing building column

Top of deck view showing internal OSHA staircase and unfinished Resindek field cut around customer’s existing building column

The materials were shipped out on a tarped dedicated flatbed, and were delivered the next day.  The customer unloaded the materials and staged them indoors near the work area.  They cleared out the room that we would be building in, and with no existing roof in the room that would otherwise need to be removed, they were all set for our installers.  Installation began on a Monday morning, and everything was wrapped up with another happy customer by lunch on Thursday.

Secure Elevated Wire Partition Tool Crib

wire_tool_crib_amezz1

By Brett

This is a project we completed in NE Ohio. The customer was looking for space for a secure tool crib for maintenance storage as well as the flexibility to store product. As the product was quite heavy, we utilized the ground floor portion for storing those items and used welded galvanized fencing above to secure their maintenance department’s tool storage. The welded wire fencing was selected because of its versatility. Welded wire partition panels have a weld at each intersection of the wire. In contrast, woven wire generally has the individual wires woven and tied off or welded to a fence frame. The welded wire option is great for most jobs because it can be cut to size in the field. If you measure inaccurately, it is not the end of the world because you can trim the extra length off the panels. Likewise, if there is piping or beams running in the way it is easy enough to cut the welded wire fence panel to accommodate the obstruction, while still maintaining the wire partition panel’s integrity.

wire_tool_crib_amezz2We utilized the existing stairs and landing from the building adjacent to the new crib in an effort to cut down cost and avoid taking up more room than necessary on their plant floor. The light you see is a reminder light for the operators of the adjacent crane. It reminds them that the mezzanine and tool crib are there so that they don’t bring their load all the way back to the stop and potentially come in contact with the new structure.

wire_tool_crib_amezz3On the front side of the mezzanine, a sliding door was in place for the occasional pallets of materials for maintenance to offload and store. The customer went with a sliding door because it could be opened, a pallet of material could be set on the top of the mezzanine deck and then the sliding door could be closed while the pallet was offloaded. With a hinged gate they would have needed to pull the pallet away from the opening to close the open fall hazard, but that wasn’t going to be feasible due to the bar grating decking.

wire_tool_crib_amezz4This customer opted for a simple keyed entry on the hinge door, but they could have used a push button or key card lock with electric strike as well.

Ultimately, they were able to have secure storage for their maintenance department while keeping their product storage below, at a price that fit their budget.

 

Cantilevered Storage Mezzanine with Wide Column Locations

mezzanine cantilevered edge

Wide span storage mezzanine with a cantilevered edge for a plastics company

By Derick @ A-Mezz

These are some photos of a mezzanine floor job we did for a site in Idaho. The contractor was looking to add a 50’ wide x 35’ deep mezzanine for additional pallet storage space in their client’s warehouse.

The warehouse’s cement pad was not initially setup to accommodate the loads from the mezzanine columns. The initial mezzanine design utilized beam and c-section framing with 12’6”x17’6” nominal column spans. While the warehouse had some existing reinforced concrete piers, they would have needed to install twelve additional footers in their pad to support the other columns. They provided us with a layout of their existing concrete piers, and asked us to come up with an option to help them limit the number of additional footers they would need to install as much as possible.

Beam and bar joist framing with extended arms on the joist allow for a cantilevered edge

Beam and bar joist framing with extended arms on the joist allow for a cantilevered edge

Utilizing a beam and bar joist frame, we were able spread our column spans out to 25’ x 28’6” nominal with a 6’6” cantilevered edge. This allowed us to set four of the six columns on top of the customer’s existing reinforced concrete piers. This also had the additional benefit of allowing for a more open space below the deck.

The customer had a couple options on how we could work around the large tapered building columns along the back wall. We could have dropped an additional column and used additional beams to frame around the center tapered building column, but the customer instead chose to pull the platform away from the wall just enough to clear them, and add some additional handrail along the back end of the cantilevered storage mezzanine for fall protection.

Unfinished resindek surface with both face and deck mounted handrail

Unfinished resindek surface with both face and deck mounted handrail

The platform was designed for a 125 pound per square foot uniform live load and used a cost effective corrugated roof deck and unfinished resindek to form the mezzanine deck.   This gave the end user a smooth surface to work on that wouldn’t peel with the rolling loads of the pallet jacks, and allowed them to store their pallets of packing materials on top of the deck as long as no pallet and pallet jack weighed over 2000 lbs.