How to Install Solar Panel Flat Roof Mounting Frame on Old Factory Buildings with Low Load-Bearing

1: Roof Structure Assessment—Starting with the Load-Bearing Capacity of the Bottom Layer

Before installing any equipment one needs to first figure out the actual bearing capacity of the roof of the old factory building. A large number of old factories do not have the original blueprints or have rather poor design standards.The first step is to hire a structural engineer to go to the site for inspection to see how many kilograms of weight each square meter of the roof can bear.Generally speaking the roof having a bearing capacity per square meter lower than 50 kilograms is the so-called low-load roof. At this moment it is not feasible to directly pile concrete blocks onto such a roof.You should choose a lightweight solar panel flat roof mounting frame. When carrying out inspections, there is a detail that needs to be paid attention to, and the roofs of old factories often have local weak parts in some areas, like around skylights, near expansion joints, and on both sides of drainage ditches.The carrying capacities of these areas can be as low as 60% of the normal areas.The layout of the bracket on your flat roof needs to avoid these areas; otherwise, a separate reinforcement will be carried out.

2: Bracket Selection—Reducing Weight Starting from the Contact Surface

Once the load-bearing capacity of the roof is determined, then comes the selection of the type of solar panel flat roof mounting frame. For low-load roofs, the traditional concrete pile ballast system is too heavy and not appropriate. Then, to select the type of support for the solar panel flat roof mounting frame, one has to first determine the load-bearing capacity of the roof first.Well then you have to take into account two rather light alternative options, don't you?First is the aluminum alloy solar panel flat roof mounting frame. The aluminum alloy which has a density approximately one - third of that of steel is still quite sturdy and can withstand the standard wind load.The second is a bracket with a base designed with perforations; this kind of structure minimizes the contact area between the base and the roof so as to reduce local pressure and makes use of multiple small ball ast boxes to disperse loads. No matter which option you select, ensure that each leg of the solar panel flat roof mounting frame is supported by a load - bearing pad of an adequate size.This mat that is utilized to disperse pressure to a larger area of the roof deck prevents the deck from being punctured.An often - used rule of thumb is that the area of the cushion ought to be at least three times the area of the base of the support.

3: Ballast Arrangement—Finding Balance Through Distribution

Although low-load roofs are unable to accommodate heavy concrete blocks，this does not mean that counterweights are completely unnecessary at all. Actually what you need is a kind of decentralized counterweight strategy.Please do not focus all the weight on those few solar panel flat roof mounting frame.The appropriate course of action is to raise the quantity of brackets while lessening the weight of every bracket. For example, if 40 kilograms of weight is required per square meter, you can utilize 20 brackets each of 2 kilograms rather than 5 brackets each of 8 kilograms.As for ballast materials, we recommend high - density composite ballast blocks. This kind of material is 20% to 30% heavier than ordinary concrete and occupies even smaller space.Alternatively, you can consider coming up with a water bag.The sealed water bag is fixed onto the mounting brackets of the flat roof, and then water is filled into it on-site. The advantage of water is that it can be drained in winter, thus reducing long-term loads.But one should be careful. The bag should be made of materials with anti - ultraviolet properties and designed in a way that can prevent leakage. Otherwise, leakage may corrode the car roof.

4: Module Layout — Optimizing Wind Loads Through Roof Design

First of all, in the low-wind-pressure area, the ballast that is required for the installation system is relatively less.Secondly, the surrounding gaps turn into a maintenance passage that can make it convenient for roof repair and such in the future. Moreover, the spacing among components is really quite important.Leaving a gap of 5 to 10 centimeters which enables wind to blow through from beneath the components and lessens upward lift research shows that this kind of layout containing gaps can bring about a decrease of 20% to 30% in the lift on the installation system.

5: Waterproofing and Finishing—Ensuring Long-Term Safety Through Joint Treatment

The final spatial level is the contact point between the roof and the installation system. The waterproof layer on the roof of the old factory is often already damaged.Even without drilling, simply placing the installation base there, over time, due to tiny movements and frictions, the waterproof layer can still be worn through.Each pedestal has to be equipped with a layer of ethylene propylene diene monomer rubber mat that is at least 5 millimeters thick. This rubber mat needs to have a moderate hardness; if it is too soft, it will be compressed and lose elasticity; if it is too hard, it will not fit the undulations of the roof.Moreover all the bolt connections on the solar panel flat roof mounting frame need to use nylon lock nuts that are used for preventing the looseness caused by vibration after installation a roof water - spraying test is recommended.For a continuous period of 2 hours, water is sprayed in the direction of the installation area, and then the signs of leakage under the roof are checked.If any leakage situation is detected, it indicates that the waterproof layer has been damaged, and at this moment, partial repair or laying another layer of waterproof membrane is required.

Generally speaking, it is feasible to install photovoltaic systems in old factories with low bearing capacities yet one has to first evaluate the bearing capacity of the roof.

From：https://extensolar.com/info-detail/how-to-install-solar-panel-flat-roof-mounting-frame-on-old-factory-buildings-with-low-load-bearing-capacity