Ensuring Proper Clearance for Roof Solar Panels
This past week we looked at a rooftop with solar panels installed almost directly on top of the flat roof surface. There was no room for someone to get even their head down underneath the the solar panels to get a good look at the condition of the rooftop. This is important from a longer term maintenance and upkeep perspective. People need to be able to ask access the majority of the roof system over time just to check conditions, remove blockages of leaves and debris and do regular inspections.
A picture of that roof from last week’s blog article follows below for reference.
In the next picture below, we show a different roof but also with photovoltaic solar panels. This roof has just a tiny bit more space, but barely enough to work. Today we’re talking about the minimum working clearance needed to really work on and fix a roof. In a case like this, shown in the next picture below, you might be able to get your head under that rooftop. There’s only about a total of 12 in of clear space and that space isn’t actually clear throughout the entire area though.
Really there’s less than 12 in all together, on average. Some solar panel companies will remove their solar panels for free if there’s a leak and it needs to be fixed, but it’s complicated to get a solar panel company out and then get a roofing company out together coordinated, in sequence. It’s much better to simply install the solar panels higher up so that there’s at least about 18 inches of clear space underneath of the solar panel system The upfront cost might be a little bit higher to build the purlin system farther above the rooftop, but it generally pays off.
Routine maintenance should be done to check the roof conditions, even when the roof is basically covered with the solar panel system. Water can still make it’s way down between the panels, so even when the roof is covered with panels, access is still needed.
While we generally recommend about 18 inches of clear space between the other side of the panels and the upper side of the roof system, we would recommend that the underside of the purlins also be installed at least 12 inches away from the roof surface. This makes it easier for a person to move between one section of panels to the next, and the 18 inch of clearance makes it possible for someone to work with their hands and arms and look at the roof system itself. It’s important to be able to see the roof system both when doing they typical and routine maintenance and checkups and also when doing repairs.
The majority of typical types of repairs of low slope or flat roof type defects or issues happens at seams and penetrations. Damage can also occur at the field of a roof membrane, but inside of the successive lap joints, the field of the membrane, if the underlayment is installed properly, rarely has problems, through the life of the roof itself. The areas of most critical concern and highest rate of defect related damages happened at the perimeter and where other pipes or items penetrate through the roof itself.
The next picture below shows a series of solar panels installed on top of an aluminum purlin system. The particular structural elements are made of aluminum because of aluminum is highly resistance to oxidation. Aluminum will actually oxidize, but it won’t deteriorate significantly, instead, when aluminum is exposed to oxygen found in typical air, the outer surface of the aluminum becomes covered with an aluminum oxide type of chemical which protects the remaining substrate material below.
Although these aluminum purlins are not nearly as strong as similar size steel beams, they are just a fraction of the weight which makes it much easier to work with in circumstances where they need to be lifted into a rooftop. Also, over the life of the roof, the purlins exert a much lower degree of pressure and bearing force against the roof itself which is helpful to extend the life of the roof. At least, in cases where these aluminum type beams are used, the steel beams are not bearing directly on top of a rooftop which could cause structural debilitation over time.
We provide this information here on our blog, and our website, to help our customers and future clients, and we recommend every building owner in DC who values the longevity of their roof (and their investments) and building use a contractor who values the simple and important principles of proper roof construction like Dupont Roofing DC. Our company specializes in flat roofing here in Washington DC and we’re happy to help building owners of almost all types.
Learn more about our company and the proper techniques of working with roofing on historic buildings in Washington DC here on our blog at DupontRoofingDC.com, and you can call us at (202) 840-8698 and email us at dupontroofingdc@gmail.com. We are happy to help and at least talk through options.
