Number of parts
Tents can be composed of 1 or 2 parts.
Tents with a single part
Tents with one part are lighter and cheaper. But they have one big drawback. Easily forms condensation on their walls.
Condensation occurs due to the contact of the humid and warm air from the inside with the cold air from outside. Condensation prevents the water vapors to pass through the polyurethane coating (PU) and outer foil (either nylon or polyester). Inside will be a stale air.
The same thing can be reached in case of models made up of two parts, if the space between the parts is small, and the two pieces are glued to each other. To avoid this, the outer material must be well stretched and well fixed in the ground.
Tents with two parts
This type prevents condensation by 2 means.
The first way is by creating an intermediate layer with a lower temperature lower than the inside, but higher than the outside. Temperature difference on the outer foil it will be smaller, and the condensation will result in a lower amount.
The second way is through the creation of good ventilation. The most important ventilation it is under the outer material foil. In case of 4-seasons models, ventilation is blocked under the outer foil by a sleeve. This is useful during snow storms, preventing its entry on the inside. Also, ventilation occurs through air vents cut into the outer foil. Thus, water vapors are evicted, decreasing result the amount of water that will form condensation on the inside of the outer foil.