It’s the bane of construction experts and architects alike: fitting as much as you can into a space that’s much smaller than what you really need. When your available space is non-negotiable, your only option is triage. In other words, you have to make decisions between the “nice” and the “necessary,” which means prioritizing things like roof supports, roof walkways, and other types of equipment and piping.
There’s no single magic layout that will work for all rooftops, but there are some standard things you need to consider. Here are some of the most important factors:
1. Equipment Specifications
Start by thoroughly reviewing the specs for all of the equipment planned for the rooftop you’re designing. Some types of equipment specs are extremely picky when it comes to ventilation, for example. If you put them too close to a wall or another piece of equipment, the resulting heat buildup could cause damage to either that piece or one in close proximity.
When you’re designing the layout for rooftop equipment, it’s easy to go down the path of “if it fits, it fits.” But roof equipment, roof supports, and roof walkways need maintenance – and they always will. It’s important to consider those maintenance needs when you’re designing the layout of your rooftop equipment. For example, you need to allow enough space between different pieces to allow workers safe access. If you build vertically, you’ll also needs steps. Likewise, make sure that a worker maintaining roof supports and equipment won’t be backing up to the edge of the roof, putting him at risk of a fall injury.
3. Building Up
When there’s no room to build out, it’s only natural to consider building up. And, while going vertical can be an excellent way to expand your available square footage, there are important factors to consider. Wind resistance is one. The higher your equipment is stacked, the more wind-resistant it has to be. Another factor is worker access. The further a worker is above the ground, the greater the risk, and the more fall protection equipment you need to provide.
Another factor that has to be considered when it comes to stacking equipment vertically is weight distribution. It’s easy to focus on optimizing space to the extent that you don’t think about load restrictions. But building up increases your weight per square foot, and that has critically important safety and structural implications.
And there’s one final factor to consider when you design rooftop equipment on a vertical plane: aesthetics. Towering stacks of heavy equipment aren’t very pleasing to the eye, and some local codes may require that you construct barriers to conceal them. Take that into consideration before you start calculating how high you can build.
Modern rooftop equipment generates much less vibration than that of previous generations, but some degree of vibration is just part of the package. The right roof supports can minimize the effect, but you still need to think about how placing many pieces of equipment in a small space could amplify the vibration. That could potentially cause damage both to other equipment and to the roof itself, not to mention intolerable noise levels for the building’s occupants.
A commercial building's roof counts for up to 50% of the available square footage and up to 25% of the building’s value, so it’s important to optimize that space. But, as with most things in life, sometimes you have to compromise. For example, if you don’t have enough room to allow adequate ventilation between pieces of equipment, you might consider going with electric instead of gas. Just make sure that, when you’re weighing your options, you give plenty of weight to things like equipment specs, accessibility, and load. Just because you can fit it on a roof, it doesn’t mean that you should.