Today, we start a two-part series on roofing equipment stands. We’ll look at the functional purpose of why they are used and some of the problems of not using roof stands for equipment. We will also talk about upkeep and maintenance of HVAC and other types of mechanical equipment on flat or low slope roofs and we will look at why its important to consider how the roof and this equipment work together to avoid conflicts.
The outline for this two-part article series follows below. Today we will start with items number one and two:
- The Functional Purpose of Equipment Stands
- Problems Associated with Omitting Equipment Stands
- Required Upkeep and Maintenance
- Avoiding Conflicts Between HVAC Equipment and the Flat Roof
The picture below shows a typical rooftop totalpac type unit installed in Washington DC where the i-beams span from structural demising wall to structural demising wall the the sides of the building.
The Functional Purpose of Equipment Stands
The equipment stands serve many functional purposes common by the main ones are 2 lift the unit above the low s**** roof system to avoid damage from the pressure of the bearing weight of the equipment. A short list of the most common purposes follow:
- Avoid bearing pressure.
- Access for maintenance and or cleaning.
- Slight elevation for gravity drains
- Required spacing per manufacturer or building code.
- Vibration isolation
Avoid bearing pressure
Generally, in our climate zone, flat or low slope roof systems, especially where installed on wood framed deck, will have isolation or recovery board installed. The recovery boards provides a better substrate for bonding with better consistency that the wood deck and avoids sharp wood splinters or metal fasteners at the wood in contact with the membrane.
At locations where equipment is set directly on top of a membrane which is set directly on top of an isolation board, the pressure or weight of the equipment will create a recess or a divot and will create a puddle area for water to pond or build up which can lead to leakage over time.
Also, single-ply membranes are generally made from resilient and flexible materials which are susceptible to being pinched or pressed between heavy objects. It’s better not to set heavy equipment directly on top of the roof membrane, for this reason.
Access for maintenance and or cleaning
You look at the top of this article at the first photograph or the photograph below common both of these pictures show examples of rooftop mechanical equipment set on a pair of steel beams. These installations happen to be bearing on the side demising walls at Washington DC rowhomes. At this type of layout come on these field beams are perfect to both lift and allow room for Access for maintenance under a cleaning and also isolate the rooftop equipment from the roof membrane itself.
Slight elevation for gravity drains
Both of the examples of the equipment set on trucks will steal eye beams are also good examples of a elevation which is also helpful in draining condensate water from the unit. In this case, a 3/4 inch PVC tube has been installed to carry water away from the unit but it only works properly if the unit is set just high enough above the adjacent roof grade.
Required spacing per manufacturer or building code
Almost every type of mechanical or HVAC equipment has a list of relatively extensive requirements for spacing. Essentially, In almost all directions come up mechanical or HVAC equipment cannot be set too close to adjacent elements coma especially construction building assemblies. In the case of a typical residential condenser unit, The building code requires at least 3 inches above the adjacent horizontal grief. In this case a platform should be installed, at minimum at least 3 inches tall. However, by installing a platform, that may also cause a conflict with other requirements of the installation, for example, having a point load or concentrated bearing on the roof membrane may also be problematic as discussed above.
Problems Associated with Omitting Equipment Stands
The main problems with a meeting equipment stands are lack of access to the area below or round the equipment, point loads which causes a divot or depression were damaged by pinching the otherwise relatively soft and pliable rooftop membrane,
All of these different types of problems or issues generally lead to a shortened Lifespan of the roof system war moderate to highly expensive remediation or repair of there are the problems.
Smart and proactive replacement, construction, upkeep and maintenance of low slope roof and mansard roof systems requires an enthusiastic interest and understanding of historical methodologies, waterproofing principles, and building science. Here in Washington DC, historic and modern residential and commercial buildings are extremely expensive and the roof and related systems provide the shield that preserves the building.
We encourage all of our clients, and all readers of this article and to our blog in general, to prioritize the value of quality construction and building maintenance, and develop a relationship with our company. You can learn a lot more on our blog. Feel free to check it out. If you have questions about the roof and related systems of your building in Washington DC, contact us or fill out the webform below and drop us a line. We will be in touch if we can help.