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.

Commercial and residential roof hatches for pitched roofs

economy series roof hatch mounted on a pitched roof

Standard roof hatch on a pitched roof

We received this set of photos from a customer who used our “off the shelf” Economy Series Galvanized Roof hatch on a pitched shingle roof like you would find in many commercial and residential locations. The standard roof hatch comes with cap flashing and 1” thick rigid fiber board insulation along the curb of the hatch. For this installation, the customer removed the curb insulation from the hatch and bolted the hatch down to the roof. They wanted the most economical roof hatch solution that had a low profile to match the roof slope. Ordinarily we would suggest using a pitch corrected roof hatch on slopes greater than 3/12, but the infrequent use and need for a low profile roof hatch was more important to the customer than the advantages of the pitch corrected roof hatch. Below are some pros and cons of each setup to help you decide which solution is best for your situation.

Open roof hatch showing clearances on a sloped roof

Open roof hatch showing clearances on a sloped roof

Economy series hatch installed on a shingled, sloped roof

Economy series hatch installed on a shingled, sloped roof








Standard roof hatch on a pitched roof pros:

  • Low cost
  • Standard sizes most likely in stock for immediate shipment
  • Low profile on roof

Standard roof hatch on a pitched roof cons:

  • Cannot use roof hatch railing (roof hatch railing may be required by OSHA depending on your site conditions)
  • Increased strain on hardware – installation on pitches 4/12 and greater are not covered by warranty
  • Decreased opening area due to roof hatch angle (see above photos)
Sample pitch correction options for roof hatch curbs mounting on sloped roofs

Sample pitch correction options for roof hatch curbs mounting on sloped roofs

Pitch corrected hatch on a pitched roof pros:

  • Larger opening for exiting on a pitched roof
  • Less strain on the hardware
  • Roof hatch railing can be installed on pitch corrected curbs
  • Needed for warranty coverage on pitches of 4/12 and greater
  • Required for larger roof hatches on pitched roofs

Pitch corrected roof hatch on a pitched roof cons:

  • Slightly increased cost (made to order)
  • Increased lead time (made to order)
  • Taller curb on low end of roof may be more visible from ground level

Using the pitch corrected hatch for your pitched roofs over 3/12 gives you the standard manufacturer’s  warranty and can give you a larger opening to go through, but ultimately it comes down to your specific needs and what is most important for you. If you have any questions, please contact us.

Stairway Visibility Through Contrasting Colored Step Nosing

By Jared @

The other day, a friend called me up to discuss safety codes in regards to stairs. He was moving his son out of his apartment and carrying the sofa down the stairs. The rubber stair treads were in terrible shape, cracked, worn through and just in general need of replacement, which of course presents a safety issue on its own. The larger issue he had called about though, was stairway visibility. The stair treads had grit stripping in the nosing – which is a sandpaper-like tape, used for extra traction and visual awareness – on all but a few of the steps, one of which was the last step before a landing. Walking down the stairs backwards, carrying one end of the sofa, the bottom step – missing the strip – blended in with the landing below it, giving the false impression that he had reached the landing. As you could guess, stepping back, thinking that he had reached the landing, caused a bit of a stumble. I’m sure we have all experienced that moment of terror, where your heart jumps up an inch, your stomach is sucked up into your chest and your breath stops for a split second that feels like minutes. Luckily for him, he caught himself before fully falling down and walked away without injury. His story made for a great discussion on the topic of contrasting color for visual awareness.

One of the highest causes for accidents on stairways is poor visibility of both risers and treads. Poor visibility can cause people to misread the edge of a step, causing them to fall. One of the best and most cost effective ways to increase visibility is by providing a visual contrast on the leading edge of treads. According to the U.S. Access Board Research, safety yellow is the most ‘visually detectible’ color. GSA9 Aluminum Stair Treads displaying a black tread with contrasting safety yellow leading edge GSA9 Aluminum Stair Treads displaying a black tread with contrasting safety yellow leading edge

Whether or not the contrasting stripes are a requirement is a debated topic across the country. Because stairs are not part of an accessible route, ‘ANSI A117.1 Section 504 Stairways’ does not technically apply to the IBC. The misconception comes from the commentary for subsection 1102.1 Design. Visual contrast is not referenced into the IBC, so it only applies if the authority having jurisdiction has specifically incorporated the requirement into their set of codes. For example, all of California does require them. Also, according to ADASAD Advisory 504.4 Tread Surface, the contrasting color is not required, but strongly suggested. If you are unsure of the requirements in your area, check with your local building inspector.


Tempered Safety Glass Windows

This past week I had a customer who had a slight misunderstanding of what tempered safety glass was, so I thought I’d take a minute to discuss just what tempered glass is and the safety features it provides.

Tempered (or toughened) glass is a type of safety glass in which chemical or thermal treatments are used to strengthen it so that it is harder to break then standard glass.  Tempering compresses the outer surfaces and puts the inner surfaces of the glass into tension.  When broken, these forces cause the glass to crumble into granular chunks as opposed to larger sharp edged pieces, and are much less likely to cut you.  This is why auto manufactures use tempered safety glass in the side and rear windows of cars.

If you’ve ever had a broken side window on your car, you’ve seen how when tempered safety glass breaks it shatters into hundreds of small grainy pieces all over the inside of your car.  If you’ve broken your windshield though, you can see a spider web of cracks throughout the window, but it typically stays in its frame as opposed to filling the car with pieces of glass.  Auto manufactures do something different with the windshields.  They use laminated safety glass.

If the goal is to keep your modular building‘s window in its frame if it breaks, you’ll need to look at either wired glass or laminated glass.

How to properly paint galvanized metal staircases and railings

What is hot dipped galvanized metal and why do people use it?

Before we get into how to paint over galvanized metal, let’s give a really quick background into what hot dipped galvanizing is and why people would do it.

Stair parts being lowered into a bath of molten zinc

Stair parts being lowered into a bath of molten zinc

Hot dipped galvanizing is a process that involves dipping steel into a bath of molten zinc. This process creates a coating that is metallurgically bonded to the steel, in essence becoming the outer layer and part of the steel itself.

Stair components coming out of the zinc bath

Stair components coming out of the zinc bath

The galvanized coating adheres to the steel at around 3600 psi, where other coatings, like zinc rich painting and zinc plating, adhere to the steel at a rate of 300-600 psi at best. The hot dipped coating has a hardness of between 170-250 DPH (Diamond Pyramid Hardness) as compared to the soft non-abrasion resistant coating of zinc rich paint or a 75 DPH hardness of zinc plating.  This is important as it shows why hot dipped galvanizing is such a popular means of corrosion resistance as opposed to other coating options out there.

How do I paint over hot dipped galvanized steel?

If you are looking for a finish other than the shiny or dull galvanization finishes (there are cosmetic differences between each in luster, but no corrosion difference between the two), you would need to do a duplex, or two part, finish to your product:  a hot dipped galvanized base layer and a painted top layer.

In order to paint galvanized metal you will need to first know whether the steel is:

  • newly galvanized (under 48hrs exposed, no zinc compounds built up on outside of steel),
  • partially weathered (day 2 to one year, some zinc compounds built up on outside of steel as well as possible dirt, grease, dust, etc.)
  • fully weathered (one year on, zinc compounds covering the entire surface.)

If the galvanizing is new you will need to profile the surface to give the paint something to adhere to. You will also need to grind down any bumps or drips that may be present from the galvanizing process as these will show through the paint. REMEMBER: Take care not to grind away the entire galvanized coating; using a hand grinder may be best practice to control pressure and grinding depth. For a partially weathered galvanized surface you will also need to remove any drips or runs, as well as the built up zinc compounds on the surface. For fully weathered surfaces you can skip those steps as the built-up zinc compounds are good for helping the paint adhere.

After you have profiled and/or prepped the surface you will need to clean the oil, dirt and other compounds from the steel. You can wipe down the handrails using a product like “simple green” to ensure there is no oil or other buildup on the material. Then you will need to use clean water to rinse the surface and dry it. Dry time to paint time should be kept to a minimum (under 12 hrs.) in order to avoid allowing any other contamination or build-ups to occur.

paint galvanized metal stair crossover

Stair crossover with yellow paint over galvanized steel handrails and stringers

What are some paints that are available for use over galvanized steel?

After the surface is clean and profiled you are ready to paint. A primer such as Sherwin Williams “pro-cryl” can be used. This primer dries fast and is corrosion resistant. You can top coat shortly after that with an acrylic coating paint like “DTM”. Check with your local paint supplier for additional options, as well as to get re-coat and cure times based on your temperature, humidity and paint thickness.


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.

Mezzanine Deck Types: Corrugated Roof Deck with Resindek

I thought it might be a good idea to begin a little series in which we discuss some of the different mezzanine deck types available.  To start things off, let’s talk about our most commonly used mezzanine deck type:  the corrugated roof deck topped with resindek.

Underside of corrugated roof deck

Corrugated roof deck, painted reflective white, as viewed from below.

As the name implies, roof decks with resindek is a two-layered mezzanine deck surface.  The structural component of the mezzanine deck is provided by a 1-1/2” corrugated steel roof deck.  The gauge of the roof deck used varies depending on the loads the mezzanine deck is designed to support.  The underside of the roof deck is painted white to help reflect light under the mezzanine deck.  The corrugation of the roof deck doesn’t offer a very useable deck surface, so it needs to be skinned with a second material — in this case, resindek.

Unfinished Resindeck mezzanine deck

Unfinished Resindek mezzanine deck surface

Resindek is a wood composite material specifically designed to provide a durable and affordable mezzanine deck surface.  There are different grades of resindek depending on the loads the mezzanine deck is designed to support.  Most commonly we will use an unfinished ¾” Resindek LD material which is designed to accommodate a combined pallet and pallet jack load of up to 2000 lbs.  If we’re designing the mezzanine to support heavier loads, varieties are available for all the way up to an 8000 lb max load.   It provides a smooth surface to roll your pallets across, both on and between panels, and doesn’t peel layers like plywood can.

Corrugated roof deck with resindek is easily our most popular mezzanine deck surface, largely due to its significant price advantage over other deck types.  There are, however, some situations where it would not be the best option.  As a wood based material, resindek can swell when it gets wet.  During installation you leave a gap between panels about the width of a nickel to accommodate some swelling, but if the deck will be in a wet environment it is not the recommended tool for the job.  In our next segment, we’ll talk about another deck type that would work better for wet environments.

Winter Weather Tips

It’s getting colder now and it’s time for some winter weather tips to keep things running smoothly whether you’re at the shop or out on the road.Snow storm traffic jam

  1. Keep a 5 gallon bucket with salt by each of your entrances along with a shovel. Snow and ice buildup can not only make it tough for people to get into your shop, it can also hinder egress in case of an emergency. Be sure to open the emergency doors and shovel/salt around them. Drifts of snow and ice can build up on the outside wall even if there is only a little snow on the ground.
  2. Have entry mats and/or a dry mop by the entrances to your shop. Wet boots trekking in snow can be a dangerous slip hazard.
  3. If you have exterior silcocks (spigots) be sure to remove hoses from them. Even if you have a frost free silcock, it will freeze with the hose attached.
  4. If there is ice on your windshield there is ice on the road. It doesn’t have to be packed up deep to be a problem. Often a thin sheet of ice can cause a big problem, especially when people aren’t expecting it.
  5. Watch the spray from tires – if spray is coming off other vehicles’ tires it’s likely the roads are wet as opposed to being ice covered.
  6. Pack extra supplies. Be sure to bring extra supplies in your truck in case you end up sitting in a back-up, stuck in the snow, wrecked or spun out. Blankets, hats, gloves, wool socks, hand warmers, energy bars, bottled water, a bag of road salt or sand, a small shovel, tow rope, booster cables and emergency flares are a good place to start.
  7. Make an electronics bag for your car. If your job requires using cameras, two way radios, cell phones, laptops or another portable electronic device like a laser level or laser measurer, pack those items all in one bag that you can take to and from your car, along with some extra batteries. Remember, in cold weather batteries are not as productive and electronics can stop working, so it is best to take them indoors with you instead of letting them chill for a prolonged time in an unheated trunk. Packing these items in one bag makes it quick and painless to take them with you.
  8. Stay dry. Whether you are directing traffic, offloading a truck, or maintaining or installing equipment, keeping dry is the first step to preventing frostbite and hypothermia.
  9. Layer properly. Cotton tee shirts offer no insulating value to you when you get it wet, yet many people still wear them as they go off to work outdoors. Natural fibers, wool or silk are amongst the best insulators when damp. There are also many good synthetic materials out that do just as well.  Remember, even if you start off warm and dry, when you work, you sweat, and when you sweat, you get damp, and when you get damp in cotton, you get cold.
  10. When working outdoors, take regular breaks from the cold. Hop in your truck for a warm beverage that you keep in a thermos. This will warm you from the inside out. Same thing goes for eating. Hot soup will warm you up quicker than a brown bagged sandwich.
  11. To help prevent your fuel lines from freezing up, keep your tank at least half full. If the vehicle is going to park for lengthy periods, fill the gas tank beforehand.

What makes a mezzanine gate a mezzanine safety gate?

We offer a number of different varieties of gates to provide fall protection on your mezzanines at your pallet access locations, but only some of them are labeled as safety gates.  Aren’t they all safety gates? While all our mezzanine pallet gates are designed to protect your personal safety while working on elevated platforms, the gates are designed to meet different standards.

Self Closing Pallet Gate

Having only a single layer of gates, the self closing pallet gate is not considered a true mezzanine safety gate.

Gates, such as our self closing pallet gate, horizontal sliding mezzanine gate, or vertical sliding mezzanine gate, help keep your employees safe while working on elevated platforms, but are not considered true safety gates.  They are all single gate systems designed to meet the federal OSHA safety railing requirements for dimensions and loading.  This means that they have a 42” hand rail, a 21” mid-rail, a 4” high toe board, and can hold back 200 lbs. of pressure.  Because they are single gated systems, when the gate is open, you have a potential exposed opening on your mezzanine.  When using a single gate system, we recommend that you mark out a 6’ bubble around the opening, train your employees to remain behind that line when the gate is open, and post signage reminding them of this at the location.

Many of these single gate systems have some additional safety features built into their design. The self closing pallet gate was designed so that instead of needing to open the gate to lift a pallet to the deck, you can lift the pallet up and push it against the bumpers of the closed gate.  As you load the pallet the spring loaded doors will open up just enough to fit the pallet, keeping the sides closed off.  When you then pull the pallet all the way through from the top, the gate closes itself.  The controls for a manual horizontal mezzanine gate are all located behind your existing handrail so your personnel will always be behind OSHA hand rail while opening and closing the gate.  Even better, the horizontal mezzanine gate and vertical mezzanine gates are both available in electric operated versions.  This allows us to add additional safety features such as strobe warning lights and adjustable timers so the gates will close after a predetermined period of time if your employees forget to shut them.  With both control boxes being field wired, you can place them in a location within view of, but away from, the opening.

Dual Interlocked Vertical Mezzanine Safety Gate

Having both a front and back gate, the dual interlocked vertical mezzanine safety gate is an example of a true safety gate

True mezzanine safety gates have both a front and back gate, and are designed to meet the voluntary ANSI MH28.3-2009 standard (Section 6.4.3) in addition to the OSHA safety railing requirements for dimensions and loading.  Operating like an airlock, the double gated system allows access to the pallet for the fork truck down below or your personnel above, while keeping a line of guard rail between your employees and the edge of the mezzanine.  The pivoting mezzanine safety gatedouble drop horizontal mezzanine safety gate and the dual interlocked vertical mezzanine safety gate are all examples of true safety gates.  If your facility is following the ANSI standards and wants to put a mezzanine safety gate in a pallet opening, make sure it is a double gated system.

Help protect your property from ‘Attractive Nuisance’ instances

By Brett @ A-Mezz

Oftentimes, people are looking for an easier way to access their roof. They may have been using an extension ladder before, renting a bucket lift, or even pulling a truck up to the wall and climbing on the vehicle.  Adding a permanently fixed roof access ladder is a great way to mitigate the cost of renting lift equipment, or increase the safety of the climber compared to using an extension ladder.

Once you’ve installed the permanent access ladder, you need to ensure that you protect yourself from having an “attractive nuisance”, or in other words, an item on your property that can be a magnet to curious kids, while at the same time providing an opportunity to cause them harm.

Generally, attractive nuisance laws start with the understanding that kids are not expected to foresee the danger all situations present. As the property owner, if there is reason to believe kids can access your property, you have a responsibility to prevent causes of potential harm. If the owner does not, the property owner could very well be held responsible for the injury to a child. Keep in mind that in many courts, kids are not just young children, but can very well be teenagers also.

What are ways to mitigate your liability? The easiest way is to be a responsible property owner. Make sure that you are following the local, state and federal laws and safety standards.  Simply do what you can to prevent access to the hazard. Just as you would lock up tanks of propane so they can’t be stolen or so that kids can’t access them, you should do the same with your ladder if it is in an area accessible to kids. A simple lockable door over the rungs of your ladder can help accomplish this. Though it will not stop someone who is determined to gain access to the roof and is willing to ‘spiderman’ up the side, or pull their car up and climb up, it will help lessen your exposure to inquisitive kids, as well as add a deterrent to opportunistic thieves and vandals. Another option, if you have the room, is to fence in the area surrounding the ladder (this also works well at the bottom of stairs accessing roofs). Again, if someone is determined to partake in criminal activities they will find a way to do circumvent whatever you do, but with regards to having an “attractive nuisance” you will have helped alleviate the opportunity for accidents.