Never overlook signs of needed roof repair, or signs that the roof needs replacing altogether, when you own a commercial building; your heating and cooling costs are probably already very high for a large commercial building, and the building's roof helps to insulate the interior. If the roof is in poor condition, this will mean even higher utility costs throughout the year. Note some sure signs that your building's roof is in need of repair or outright replacement, and then call a roofing contractor as needed.
As said, the roof of your commercial building helps to insulate the interior, and this includes protecting it from moisture and humidity. If you notice water stains on the roof, high humidity levels during summer months, and an increase in insects and rodents in the building, these are all signs that the roof is in disrepair and allowing in too much humidity. Adding a dehumidifier alone probably won't fix this issue as these are often not powerful enough to remove humidity through a large commercial building, and remember that added moisture inside the building means that your air conditioner needs to work harder to keep the interior space cool. Fixing the roof or having a new one installed is the best option when it's allowing in excess moisture.
Many commercial roofs will have a protective membrane or coating installed over them, for added protection and to ensure no water collects on a flat roof. If you're on the roof and notice bubbles forming along that membrane, you need to have the roof recoated or the membrane replaced. These bubbles are a sign that the membrane is becoming soft and weak, and you may soon see splits or holes in the area of those bubbles. Then, the roof may leak. Rather than waiting for this to happen, have the roof repaired or replaced once you notice that bubbling.
Lack of waterfall through the downspouts
When it rains, the water should run off the roof, through the gutters and into downspouts. If it seems like there is less water coming out the downspouts than should be expected, given the volume of rainfall, this often means the roof has holes and other such damage. The roof may be absorbing water and allowing it to seep into the building materials under the roof itself, rather than the rain running into the gutters and downspouts. In some cases, you may only need to have the gutters cleaned so water can run through them, but if these are clear of debris, it's good to then check the roofing materials for damage and needed repair or replacement.