A folding door was installed through the entrance to the living room and terrace, and a folding door was installed through the window in the bathroom on the second floor.

When the folding door is folded to open the space, ventilation is carried out with faster air circulation at a wide opening/closing rate, and the open view provides a more expanded space effect. Polzen Korea's sole patent, the rack gear handle, allows easy and light opening and closing operation without the need for a separate auxiliary handle. Our family's cozy space has a sufficient interior effect, as well as high airtightness and airtightness when all of them are closed, so the quality of life has been improved as a comfortable living space with high insulation, soundproofing, and windproof functions.

An insect screen, also known as a wrinkle screen, was installed with a folding door. This screen is a driving screen that pulls and pushes and folds the screen like a bellows.​

Due to the nature of the mountain, bugs may enter the interior or fall tree leaves may accumulate on the terrace floor. Even if the folding door is opened, it can be blocked with a screen to maintain a clean interior. Also, you can't just open and close 100%, but you can open and close as much as you want!

The gap is so tight that mosquitoes and fruit flies can't pass through. It is a mysterious and smart wrinkle screen that protects the indoor space from pests.