We need extra quilts in winter to keep warm, but apparently buildings need them too.
A set of dramatic drone images have emerged showing over 200 quilts being placed on the rooftop of a newly built structure in east China.
The colourful cotton quilts cover an area of 2,000 square metres (22,000 square feet) and are supposed to prevent the building from 'freezing' in cold weather, the workers told local reporters.
Over 200 colourful cotton quilts are placed on top of a new building by construction workers in Ji, China on February 6
It's believed the quilts could keep the concrete at a certain temperature and prevent the material from freezing in winter
It's stated that freshly poured cement might not be dried out completely in cold weather, and it could cause frost damage to the building.
Drone pictures taken on February 6 capture hundreds of bed covers being laid out on top of a new building on Liuchangshan Road in Ji, Shandong Province.
Workers used heavy boards to secure the quilts and prevent them being blown away by the wind.
As stated by China Economic Net, the layer of protection can ensure the strength of the cement in low temperatures, as well as keep the concrete building from being damaged.
The temperatures of Ji on the day dropped to nine degrees Celsius, which is a record low.
The cotton covers can trap heat on the surface, keeping the building 'warm' when the temperature drops below zero
The freshly placed concrete would take longer time to settle in winter than in warmer months, therefore it needs protection
Apparently, freshly placed cement would be no fit to use if the works were carried out below zero-degree temperatures, according to post from Wilkinson Construction Consultants, a UK building inspector company.
The post, which quoted leading building material company Cemex, stated that the water in the concrete mix would freeze and expand.
But if the weather is below five degree Celsius, it would a longer than normal for the cement to develop strength.
Cemex suggested frost blankets and insulated formwork bed used for protection. They should be placed above the exposed area or erected to ensure the concrete is free from ice and snow.
If precaution is not being taken, the cement would be of no fit to use because the water in the mix would freeze and expand
The temperatures in Ji remain cold during the week. It hit a record low of minus nine degrees Celsius in early February