With the continuous development of society, people are increasingly pursuing their own standard of living. In outdoor activities, composite decking has gradually become an alternative to traditional wooden flooring due to its various excellent characteristics. But many homeowners are concerned that if composite deck is built outdoors and exposed to sunlight for a long time, it may become hot? The simple answer is yes – like most outdoor materials, composite decking get hot also absorbs heat, but its degree of heating is influenced by various factors. This article will provide a detailed introduction to material properties, comparative data, and cooling techniques.
Why Does Composite Decking Get Hot in the Sun?
Composite deck is made by mixing wood fibers with plastic polymers. This combination can combine the excellent properties of wood and plastic, such as corrosion resistance and insect resistance, but it also causes the material to absorb heat and accumulate heat in sunlight. The main reasons are as follows:
Color selection
Dark colored composite deck (such as dark brown, black, walnut) is more likely to absorb heat than light colored decking (light gray, beige), resulting in a significant increase in surface temperature.
Material composition
The breathability of plastic components such as polyethylene or PVC is inferior to that of natural wood, which reduces the volatilization of heat.
Light intensity
An open area without any obstruction throughout the day can cause the surface temperature of the floor to be much higher than in a shaded environment.
What is the Actual Temperature of Composite Deck?
1. Material Characteristics of Outdoor Composite Deck
Material: Mainly made of wood plastic composite materials, including wood powder, plastic, UV resistant additives, etc.
Thermal conductivity: slightly higher than wood (thermal conductivity coefficient of about 0.2-0.3W/m-k), but lower than stone or metal.
Thermal expansion coefficient: approximately 5 × 10 ⁻⁵/℃ (expansion joints need to be reserved to avoid expansion caused by high temperatures).
Temperature resistance range: -30 ℃~70 ℃ (short-term high temperature resistance can reach 80 ℃).
2. Temperature Test Data Under Different Environments
Summer High Temperature and Sun Exposure Environment
| Condition | Surface temperature range | Notes |
| Temperature 35℃, direct sunlight (dark color) | 55-75℃ | Black/dark gray floor absorbs significant heat |
| Temperature 35℃, direct sunlight (light color) | 45-60℃ | White/light colored floors have high reflectivity and slow heating |
| Cool and shady place (temperature 35℃) | 35-40℃ | Close to the temperature, with a gentle touch |
Low Temperature Environment in Winter
| Condition | Surface temperature range | Notes |
| Temperature -10℃, dry and without sunlight | 28-33℃ | Hardness increases at low temperatures, but it is less prone to cracking |
| Temperature 0℃, snow cover | -5~0℃ | Snow insulation to slow down temperature drop |
Rainy/Humid Environment
| Condition | Surface temperature range | Notes |
| After rain (temperature 30℃, humidity 80%) | 28-33℃ | Water evaporation absorbs heat, and the surface temperature drops significantly |
| Continuous rainy weather (temperature 25℃) | 22-26℃ | High humidity, improved thermal conductivity, cool touch |
3.How to Test Composite Decking Temperature and Heat Retention
Tools: Infrared thermometer (measuring surface temperature)+data logger (monitoring 24-hour temperature changes).
Test point:
Direct sunlight area (12:00-14:00 noon).
Shadow area (compared to temperature difference).
Near the water source (such as by the pool, test the coupling effect of humidity and temperature).
Reference standards:
ASTM D7032 (Outdoor Composite Material Weather Resistance Test).
EN 15534 (WPC Floor Thermal Expansion Coefficient Test).
4 Effective Ways to Cool Down Composite Decking Get Hot Weather
If composite deck is chosen for outdoor terraces, the problem of high temperatures can be alleviated through the following methods:
Color selection
If you are in an area north of the Tropic of Cancer, you can choose dark colors because the sunlight is not as strong and the temperature is low, absorbing sunlight and storing heat. If it is located near the equator, priority should be given to choosing light gray, beige, or ivory colored flooring. Light colored decking can reflect light and effectively reduce heat accumulation.
Increase shading facilities
Install sunshades, pavilions, or large umbrellas to reduce the area of direct sunlight.
Laying outdoor carpet
Prevent breathable and anti slip outdoor carpets in daily activity areas, and isolate high-temperature surfaces.
Ensure ventilation design
Maintain appropriate board spacing during installation to promote air circulation and increase floor heat dissipation.
Summary and Purchasing Suggestions
Composite decking get hot in sunlight, but with proper design, it can effectively control temperature. Attention when purchasing:
View product specifications: Some brands have launched the “low thermal sensitivity” series, which uses reflective coating technology.
Considering climate conditions: Light colored, high-density composite materials are preferred in hot areas.
Combined with vegetation shading: planting climbing vines or trees to naturally cool down and beautify the environment.
