If you’ve ever installed a metal roof on a customer’s home and gotten a call from that customer some time later complaining that the roof is “sweating”, do a bit of detective work before you rush out to assess the damage from your installation. For one thing, metal simply can’t sweat. Chances are the so-called leak in the ceiling of the home is due to condensation.

Technically speaking, condensation is “the process by which matter transitions from a gas (or vapor) phase into a liquid phase”, in physics terms. Metal roofs do get cold and when moisture in the attic space comes into contact with that cold (a temperature below the dew point) surface, condensation is the end result.

Fixing the Problem

The problem is the presence of moisture. This could be due to a deficiency in the moisture barrier in the attic. Then again, the culprit could be improperly installed light fixtures, vent pipes, or ceiling fans – all of which could allow moisture to bypass an installed barrier. Sealing these fixtures could solve the problem quite simply.

If the moisture in the attic space is coming from a bathroom or kitchen, the exhaust fans or even a dryer vent could be allowing the seepage. The best solution to this type of problem is rerouting the vents so air is pulled to the outside of the home rather than accumulating under the roof.

Then again, the trouble may be a bit more severe. If the condensation isn’t due to unwanted moisture seeping into the attic space, then the problem might be caused by inadequate ventilation. The ideal situation is to ensure air is distributed evenly between the ridge and the eave as well as providing an unobstructed path for air to enter at the soffit and then disperse after following the ridge. Sometimes it’s difficult to provide the right amount of ventilation and in this case, a power vent or gable vent might do the trick.

Installing a Metal Roof the Right Way

The best offense is a good defense. The next time you install a metal roof, be sure that it is placed over a solid deck with a high quality synthetic underlayment. This is the best way to ensure that moisture doesn’t ever contact the metal roofing directly – and condensation doesn’t ever occur.

If the installation of the new metal roof is going over the top of an existing roof, it’s still best to lay down a good underlayment first. This also helps when the roof gets hot; the underlayment will hold up nicely and ensure the integrity of the roof.

At Kay Supply, we’re here to help. If you ever encounter a problem that you can’t find a solution for, just ask us and we’ll be happy to share our experience and expertise.