Estimating Normal Duration of Renovation for Multistory Apartment Building Considering Extension-Type Renovation Projects

Abstract

Normal (typical) project duration is estimated at the initial stage of a renovation project and is an important reference for project control. However, its estimation has not been researched extensively owing to the complexity and uncertainties of renovation. Thus, a model was developed for predicting the duration of sustainable apartment renovation. Experts were asked to estimate a baseline schedule for extension-type renovation projects, factors that influence critical path activities, and the range of project durations considering these factors. An equation for estimating the duration of a renovation project was developed, and the range of project durations was derived using a MCS to reflect uncertainty. The proposed model was validated by applying it to actual cases. The case study shows that the model would be more suitable for complex renovation construction (i.e., more than two buildings or vertical extension). The model can be applied to various renovation projects and used as a reference for determining contract time. It can fill the knowledge gap of construction duration forecasting by adapting the concept of control activities to simplify the assessment of uncertainties in renovation of apartments, and can be applied for forecasting sustainable renovation time for other project types or in other locations.

Technical Feasibility Study Model of Aged Apartment Renovation Applying Analytic Hierarchy Process

“…Yeon et al (2014) supplemented the net present value technique applied to the feasibility evaluation of apartment renovation in Korea and conducted a feasibility study reflecting the renovation process. Yoon and Yu (2019) studied project duration predictions for vertical extension renovation of apartments. They classified the renovation project process, and applied the Monte Carlo simulation to predict the project period.…”

“…Building renovation is widely embraced because it creates a pleasant and sustainable living environment and reuses resources (Baek & Park, 2012). Residential buildings are being renovated around the world, especially apartments, and their solutions are becoming increasingly important (Kaklauskas et al, 2013;Yoon & Yu, 2019). In Korea, a representative housing type is the apartment, which accounts for more than 60% of the total housing (Moon, 2020).…”

“…Additionally, the number of apartments over 20 years old exceeds 4.7 million (Kim et al, 2020). In particular, many apartments built in the Seoul metropolitan area to solve housing shortages in the 1990s are now aging and becoming a significant problem (Choi et al, 2018;Yoon & Yu, 2019).…”

“…Reconstruction is a method of dismantling an existing construction and building a new one, while renovation is a method of improving and repairing the structure of an existing building (Choi et al, 2018). Apartment renova-tion in Korea includes not only the repair and expansion of the household floor, but also the vertical extension of the upper section of the building and the extension of the underground parking (Yoon & Yu, 2019;Seo et al, 2021). Figure 1 shows the concept of extension-type renovation.…”

“…However, residential building renovation feasibility studies have mainly focused on economic feasibilities such as the costs and project profitability (Hopkins et al, 2006;Boeri et al, 2011). Similarly, feasibility studies of apartment renovations in Korea tend to be evaluated based primarily on their economic feasibility and business efficiency -such as return on investment and project timescale projections (Yeon et al, 2014;Koh et al, 2019;Yoon & Yu, 2019). The problem is that many apartments earmarked for renovation based on a pre-evaluation process that considered economic feasibility alone, did not actually complete the renovation process.…”