Sweating pipes can be a common feature in any moisture laden environment. Pipes are most likely to sweat when the water inside the pipe is much colder than the air surrounding it. This sweating or condensation can be observed as water droplets dripping from the pipe and may often be mistaken as a leak.
However, sweating pipes do not suffer from actual leaks but rather water droplet accumulation on the surface of the pipe. Here are some reasons why pipes sweat and what to do about them.
Sweating Pipes in Summer
Condensation, the accumulation of airborne moisture on top of cool surfaces, may occur at any time when plumbing components become cooler than its surroundings. During summertime, the air surrounding the pipes is naturally hot and the water running inside the pipes has a cooler temperature. This difference in temperature allows the warm humid air outside to form drops of moisture upon reaching the cold surface of the pipe, resulting in condensation.
Sweating Pipes in Winter
Likewise, in the winter, home interiors are kept heated by the furnace making the air outside the pipes much warmer than the cold water inside them. For the same reason, pipes continue to sweat despite the overall cold temperatures of winter.
When humidity is added into the equation, especially in the case of basements or bathrooms where damp conditions tend to prevail, sweating pipes become a year round phenomenon.
Sweating Pipes with Water in Them
Since condensation can occur on all types of cold water supply piping materials, it is not uncommon to notice that some parallel running pipes show signs of condensation and others do not. This is not due to leaks but because of water running in them. The pipes with the condensation indicate cold water flow carrying water from the relatively cold ground outside, while pipes with no condensation are likely carrying little or no water.
The dry pipes may be connected to fixtures that are not used often or faucets that are not turned on much. However, when these pipes do start to carry cold water, they will also start to sweat.
Curing Sweating Pipes
One effective way for moisture regulation around pipes is to insulate them. This can be done by applying self-adhesive drip tape to the pipe’s surface to prevent condensation. To apply, first wipe the pipes as dry as possible and wind the tape tightly over the pipe surface and other fittings. The pipe surface should ideally be covered fully so that the warm, humid air does not touch the cold metal of the pipes.
Sometimes people choose to use fiberglass pipe wrap to treat plumbing sweating pipes, but this is not a good recommendation since fiberglass is not waterproof. Instead, it holds the potential to absorb water and may need to be reinforced with an additional plastic vapour barrier. This is just extra work which can be avoided by using plastic foam pipe wrap instead.
Plastic foam pipe wrap is available in different lengths that can be further cut or mitred to fit the pipe and its corners. Seams can then be wrapped up with duct tape.
Finally, in instances where plumbing fixtures and attached pipes are visible, detecting sweating pipes is quite obvious, but the same can also happen in hidden supply pipes or those screened by walls. This type of accumulated and unseen condensation on pipes sweating in walls can be a potential breeding ground for mold and mildew as well as a cause for indoor stains on walls and possible flooring damage.
Controlling Basement Humidity
In the case of basements, it becomes very important to lower the dew point of the area, meaning that the basement air needs to become drier to prevent pipes from sweating. This can be achieved by installing a dehumidifier on the premises. The dehumidifier will help dry out the basement air while removing the excess moisture in a controlled way.
In addition, a simple box fan may be used to circulate the air in the area, so that the damp air rotates well and becomes drier when traveling past the dehumidifier. Other than the sweating issue, it is also important to keep basement humidity levels lowered, since these can also become the cause of mold, mildew, musty odors, and unhealthy air.