[단독]Lee Hwi-jae couldn’t escape too ‘Murder Impulse’ touches the core noise between floors

The government has started to improve the system related to floor noise, which also causes murderous urges. On the 26th, the Ministry of Land, Infrastructure and Transport held a meeting on interfloor noise in four large domestic construction companies. At this meeting, a plan to clarify the’post-check system’ related to floor impact sound blocking performance announced last year, as well as a plan to make the slab (reinforced concrete floor) thickness obligatory from 210mm to 240mm were intensively discussed. It is going to strengthen what was legislated in 2013 to have a thickness of 210 mm.

Resolving the interfloor noise problem is one of President Moon Jae-in’s 100 national tasks. However, as the recent comedian Lee Hwi-jae and couple officially apologized for the issue of inter-floor noise, the conflict has increased significantly. As the time to stay at home is getting longer due to Corona 19. Lifestyle habits are important to prevent noise between floors, but there are also voices that the construction method needs to be changed. An official from the Ministry of Land, Infrastructure and Transport said, “We are considering various aspects of improving the architectural system to solve the problem.”

There is a way to solve the floor noise. You can increase the floor height of the apartment, change the wall structure to a column structure, and increase the thickness of the slab. In the case of reinforcing the slab thickness standard, which is being considered as the most promising method, the industry believes that when the thickness is 240mm, the noise is reduced by 1.5dB (based on the weight impact sound).

The thickness of apartment slabs continues to increase along with inter-floor noise problems. From 120mm in the 1990s to 150~180mm in the 2000s, and strengthened from 2013 to 210mm. However, even if the slab thickness is 240mm, it is somewhat difficult to meet the government’s sound insulation performance standards. In 2005, the government introduced a’floor structure accreditation system’ in which floor impact sounds were measured and graded in a laboratory in advance to prevent interfloor noise.

According to the standard, the light impact sound (medium high frequency) generated when objects are dropped must be 58dB or less, and the heavy impact sound (medium low frequency) generated when children are running must be 50dB or less to pass. An official in the construction industry said, “The legalization of the weight impact sound standard is the only one in the world, and the standard is too high, and even if the slab thickness is made thicker, there is a limit to fundamentally preventing interlayer noise.”

It is also a way to increase the floor height. There is less noise between floors in an office building (3.5~4m) with a higher floor height than an apartment (about 2.9m). There is also a difference between wall structure and column structure. The high floor height provides a cushioning function, and the way noise and vibration are transmitted is also different. It is evaluated that the wall structure, where the wall is a structure, transmits noise directly from the wall to the floor, whereas the column structure transmits less sound and vibration. The problem is cost. The construction cost of the column structure is about 20% higher than that of the wall structure. If the floor height is increased, the number of furniture that can be built at the same height will be reduced, which reduces business efficiency.

Another construction industry official said, “There is a limit to the construction cost due to the upper limit on the pre-sale price,” he added. “There have been cases of thicker slab construction recently, but the situation is mainly promoted for publicity purposes, mainly for complexes with good business feasibility such as the Gangnam reconstruction site in Seoul.”

The’responsible material’ is also controversial as the Ministry of Land, Infrastructure and Transport announced that it will change the pre-recognition system related to floor impact sound to the post-check system last year. In 2019, the Board of Audit and Inspection announced that 96% of the blocking performance was inferior to those previously recognized when measuring the inter-floor noise of 191 apartments scheduled to move in. It was pointed out that the prior accreditation system in the laboratory was not famous.

Floor construction is usually completed by placing a cushioning material that mitigates the floor impact sound on a concrete slab and installing a heating pipe. The cushioning material manufacturer argues that construction deviations at the construction site are the problem, and the construction company is adamant that there is also a problem of the cushioning material companies that bring in inadequate materials to target the loophole where the cushioning material is not visible after construction.

The Ministry of Land, Infrastructure and Transport explained, “If the post-confirmation system is enacted and implemented in a complex that has been approved for project implementation from July 2022, the problem will be improved as construction companies’ awareness of quality control will increase.”

It has long been pointed out that apartment residents should improve their lifestyle habits. In the case of foreign countries where apartment houses, such as apartments, are usually operated as public rental housing, a’three-jin out’ system is operated to evict the residents who caused the problem when a problem related to interfloor noise occurs among residents. The fine rules are also strict.

Reporter Han Eun-hwa [email protected]