Indoor Pools & Water Vapor, What You Need To Know

Indoor pools are very unique. The water vapor escaping from the pool is trapped in the building envelope. These vapors are potentially corrosive, as they contain chlorine, chloramines, or ozone. The water can have destructive consequences and pose serious health issues if the building is constructed incorrectly.

Dehumidification for Indoor Pools

There is no such thing as an oversized dehumidification system. But the lack of a dehumidifier (or an undersized one) allows the water vapor to accumulate and penetrate the building envelope. Water vapor inside the walls can cause corrosion of the structural beams, braces, and brackets, corrosion of the wiring and electrical components, foster mold and algae growth, rusting of HVAC ducts, or promote dry rot of wooden elements. Excess water vapor in the building can lead to a series of air-borne health maladies or bacterial infections.

Been There, Done That

Cheap clients who do not want to pay for the installation or operation of a dehumidification system, think that they can reinvent the wheel with exhaust fans, sliding doors, skylights, ceiling fans, or other schemes. Trust us, they have been tried countless times without success.

Proper Building Envelope for Indoor Pools

It is important to install a vapor barrier and use moisture-resistant construction materials to prevent the migration of moisture into the walls and ceiling. Electrical outlets, fixtures, and penetrations must be sealed against vapor intrusion.

Air Pressure in Indoor Pools

The air pressure within the swimming pool enclosure must be less than the adjacent spaces. Maintaining a high pressure in the adjacent spaces ensures that the water vapor does not migrate.

Operational Cost

Operating a dehumidification and air handling system to control the air pressures, temperatures and humidity are expensive to operate. Failure to operate these systems properly will result in vapor migration and degradation of the building. Maintaining the proper temperatures is also important in controlling the creation of water vapor (evaporation).

Automatic Pool Cover

Using a pool cover does not eliminate the need for a dehumidification system. It will help reduce the vapors, but it will not eliminate them. The installation of a cover allows for the reduction in the size of the dehumidification system, as the loads are reduced.

Qualified Indoor Air Quality Expert

We do not profess to be experts in this field. Though we have built a number of indoor pools, we rely upon specialists in this field. Most mechanical engineers or dehumidifier manufacturers do not possess the skills to properly design the HVAC/Dehumidification system, vapor barriers, building envelope, ducting sizes, or air handling register/return locations.

Non-Corrosive Air Ducts

Properly constructed indoor pool air handling systems utilize non-corrosive plastic ducting, registers, and returns. Galvanized sheet metal ducting quickly begins to corrode in an indoor pool environment. Indoor pools can be a source for year-round enjoyment of a pool. But they require a properly designed and built enclosure, in order to protect the rest of the building and occupants’ health.

Swimming Pool Expert Witness