Condensation in Marquees & Gazebos

Why It Happens and How to Reduce It

Condensation inside a marquee or gazebo is one of the most commonly misunderstood issues in temporary outdoor structures.

Many people assume moisture inside a marquee automatically means the structure is leaking. In reality, condensation is often completely natural and can occur even inside fully waterproof marquees.

Understanding what causes condensation, how to reduce it, and how to spot the difference between condensation and genuine water ingress can help protect your marquee, improve guest comfort, and avoid unnecessary concern during events.

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What Causes Condensation in a Marquee?

Condensation forms when warm, moisture-filled air comes into contact with colder surfaces.

Inside a marquee or gazebo, this usually happens when:

the temperature inside the structure is warmer than outside
moisture builds up in the air
ventilation is limited
cold external temperatures cool the roof or sidewalls

As the warm air cools, water vapour turns back into liquid and forms droplets on the inside of the structure.

This process is very similar to condensation forming on:

windows
patio doors
conservatories
vehicles
commercial buildings

Even fully waterproof marquees can develop condensation under the right conditions.

Why Condensation Is Common in Marquees

Temporary structures naturally create enclosed environments where heat, moisture, and airflow constantly interact.

Several factors can increase condensation levels inside a marquee or gazebo.

Large Numbers of Guests

People generate significant moisture through:

breathing
body heat
perspiration
cooking
hot drinks
dancing and activity

The more people inside the structure, the more humidity builds within the enclosed space.

This is particularly common during:

weddings
parties
hospitality events
catering operations
evening events during colder months

Temperature Differences

Condensation becomes much more noticeable when there is a large difference between indoor and outdoor temperatures.

For example:

cold evening temperatures outside
heating systems operating inside
warm air trapped within enclosed sidewalls

This creates ideal conditions for moisture to form on colder marquee surfaces.

Ground Conditions

The surface underneath the marquee can also affect humidity levels.

Grass, damp soil, and recently wet ground naturally release moisture into the surrounding air. When enclosed by sidewalls, this moisture can become trapped inside the structure.

Marquees installed on:

grass
muddy surfaces
wet ground
riverside locations
humid environments

are generally more prone to condensation.

Limited Airflow

Poor ventilation is one of the biggest causes of condensation build-up.

Without airflow, warm moist air remains trapped inside the structure and settles against colder surfaces for extended periods.

This increases the likelihood of visible moisture forming on:

roof covers
windows
sidewalls
framework sections

Condensation vs Water Leaks

One of the biggest misconceptions is confusing condensation with a leaking marquee.

In many cases, what appears to be a leak is actually moisture formed internally through temperature and humidity changes. If water appears evenly across the inside surface of the marquee roof, condensation is often the most likely explanation.

**Common signs of condensation in a marquee**
Condensation	Water Leak
Moisture spreads across wide roof areas	Localised dripping point
More noticeable overnight or in colder weather	Constant water entry regardless of conditions
Linked to guest numbers and heating	Usually linked to damage or poor sealing
Forms on internal surfaces	Often enters through seams or tears
Appears intermittently	Usually repeatable in rainfall

Are Gala Tent Marquees Waterproof?

Yes.

Gala Tent marquees and gazebos use waterproof PE and PVC materials designed to resist rainfall and outdoor weather exposure.

Our covers are manufactured using durable weather-resistant materials developed for outdoor event use, including:

waterproof PVC
waterproof PE
UV-resistant coatings
reinforced seams
tensioned cover systems

However, waterproof structures can still develop internal condensation under certain environmental conditions.

The presence of condensation does not necessarily indicate a fault with the material or structure.

How to Reduce Condensation in a Marquee

While condensation cannot always be eliminated completely, it can often be reduced significantly with good setup and ventilation practices.

Improve Ventilation

The most effective way to reduce condensation is improving airflow.

Where possible:

partially open sidewalls
open doors periodically
create cross-ventilation
avoid fully sealing the structure unnecessarily

Fresh airflow helps humid air escape before moisture collects on cold surfaces.

Avoid Excess Internal Moisture

Activities that generate steam and humidity can rapidly increase condensation levels.

Examples include:

cooking
boiling water
hot beverage stations
drying wet clothing
storing damp items

Where practical, cooking and catering operations should ideally take place in separate structures or well-ventilated areas.

Use Heating Carefully

Heating can improve comfort during colder weather, but it can also increase temperature differences between the inside and outside of the structure.

To help minimise condensation:

combine heating with ventilation
avoid excessive enclosed heat build-up
maintain steady airflow where possible

Keep Covers Properly Tensioned

Loose covers can encourage water collection and uneven airflow across the structure.

Correctly tensioned covers:

improve water runoff
reduce flapping
improve airflow around surfaces
help maintain overall structural stability

Regularly check:

straps
fixings
tie-downs
roof tension
anchoring points

during use.

Use Flooring Where Possible

Flooring systems can help reduce moisture rising from grass or damp ground.

This can be particularly useful for:

long-duration events
winter hospitality
catering operations
semi-permanent installations

How to Prevent Mould & Mildew

If moisture remains trapped inside covers for extended periods, mould and mildew may begin developing.

To help prevent this:

fully dry covers before storage
ventilate regularly during use
avoid storing damp sidewalls or roof sections
clean surfaces periodically
inspect covers after wet weather use

For tougher cleaning requirements, PE and PVC-safe cleaning products should always be used.

Can a Dehumidifier Help?

In some situations, yes.

Industrial dehumidifiers may help temporarily reduce moisture levels during:

winter events
enclosed hospitality use
extended wet weather periods

However, marquees are not airtight structures, so dehumidifiers should generally be viewed as temporary moisture management rather than a permanent solution.