What is Roof Condensation?

Condensation: When warm comes in contact with cold surface its water vapor cools down and condenses to form water droplet. This process is known as condensation. It is the reverse of vaporization. It is the changing of the physical state of gas into a liquid state.

Roof Condensation: Building envelope separates the outer exterior from the inner one. Walls, roof and foundation act as a barrier to the outer surroundings. The insulation in the roofing system is designed to prevent heat loss from the building or to prevent heat gain from outside of the building. Within the insulation, the temperature slowly changes until it reaches outside. Inside the insulation layer, the temperature gradually drops until it reaches the outer surrounding which has a colder temperature. As the air migrates up the roof it becomes cooler until the point where it cannot hold its vapor state and condensation occurs.

Roof Condensation

Roof condensation is hard to notice without a professional inspection.

Primary causes:

Condensation issues occur when excess moisture from inside the home collects inside the attic air space, where it eventually cools and condensates. Some items and activities within the home that add excess moisture include:

1) Fireplaces & firewood

2) Space heaters

3) Cooking

4) Showering & bathing

5) Saunas, hot tubs and Jacuzzis

6) Dishwashers

7) Washers & dryers

8) Humidifier

Condensation in the loft after insulation:

The benefits of loft insulation are well documented except one. After insulation it is difficult to get rid of warm air moisture because there is no passage for air circulation so when the warm air rises up and when it comes in contact with the cold roof tiles it will condense into water and cause condensation. Condensation In loft after insulation is a primary complaint.

New builds:

In new built properties condensation is a problem because new built use wet trade building problem such as cement, plaster ETC as these materials are mixed with water therefore contain large amount of moisture. When they dry out they release moisture into the air and when this moisture rich air collide with cooler surface such as wall or roof condensation occurs.

Un-insulated loft hatches:

Poor insulated or badly fitted loft hatches allow air and moisture to enter the loft space. When loft is unable to breathe accumulated air moisture it will come in contact with the cold surface of roof, this warm air will condense and water will flow down the inside of the roof and cause dampness in the loft space.

Poor ventilation:

Many modern roof designs now incorporate ventilation at both eaves while some buildings have poor ventilation or no ventilation at all.

Solutions for condensation:


Venting keeps the moisture in the air balanced because it provides adequate air flow to remove moisture. Balancing roof and attic venting is difficult but it is not a problem for experienced technicians.

Un-cool roofs:

Cool roofs are growing in demand because they keep the house temperature lower mainly in summer months and saves owners air conditioning bill however in winter this can come back to bite homeowners as the extra-cool roof encourages condensation. For particularly bad condensation cases, a change in roof color or composition may be advantageous. If you are considering a cool roof, think about condensation’s potential effects as it relates to the climate you live in.

Insulation and vapor barriers:

Insulation reduces moisture issues and indeed keep a roof warmer. Insulation also reduces moisture buildup. These products can be installed into the roof without major renovation. However, insulation and vapor barriers have the opposite of cool roofs’ problem. In summer, they may cause even worse roof damage.


If you think your roof has condensation, give us a call and we’ll check it out. Our Roofing Company Little Rock will get the job done quickly and an affordable price!