Time Estimation for Renovating a 2,000 m² Warehouse Roof Using the Phasing Method

Introduction

Renovating a 2,000 m² warehouse roof is a medium-scale project that demands careful time planning so that warehouse operations continue running normally. Shutting down all warehouse activity during renovation is certainly not an economical choice, especially for companies with daily shipping cycles. This is where the phasing method (staged execution) becomes the preferred solution for many modern warehouse owners.

As a company experienced in the installation and renovation of lightweight steel roofs, PT. Bajaringan Industri Sejahtera has handled numerous warehouse projects using the phasing method. This article discusses in detail the time estimation for renovating a 2,000 m² warehouse roof using the phasing method, complete with simulations, factors affecting duration, and acceleration strategies without compromising quality.

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1. Understanding the Phasing Method Concept in Roof Renovation

Phasing is a renovation execution method that divides the roof area into several zones (generally 4–6 zones) worked on alternately. Its main goal is to keep part of the warehouse operational during the renovation.

Several factors determine the number of phases:

• Area size to be renovated.
• Criticality level of stored goods in each zone.
• Material access and heavy equipment mobility paths.
• Warehouse operational schedule that must not be disrupted.

The fundamental difference between phasing and the conventional (simultaneous) method lies in time and operational risk. The simultaneous method is indeed faster, but requires the warehouse to be completely empty. Conversely, phasing takes longer but allows the warehouse to remain 70–80% operational.

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2. Basic Time Estimation Based on Area and Type of Work

The standard productivity for lightweight steel roof installation we use in the field is 25–40 m² per day per team (4–6 people). Assuming an average productivity of 30 m²/day, the theoretical estimate without phasing is:

2,000 m² ÷ 30 m²/day = ± 67 working days (about 3 months)

Work details include:

1. Old roof demolition (1–2 days per zone).
2. Lightweight steel frame installation (main work).
3. Roof covering installation (spandek, metal tiles, or similar).
4. Finishing: flashing, gutters, insulation, and waterproofing if needed.

Weather factors and curing time (especially for waterproofing work) must also be considered, particularly during the rainy season.

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3. Factors Affecting Duration with the Phasing Method

Several key factors affect the total duration:

• Number of phasing zones: the more zones, the longer the total time due to transition periods between zones.
• Work overlap: whether zones are partially worked simultaneously or strictly sequential.
• Availability of labor and materials on site.
• Existing structural condition: repairs to columns, trusses, or purlins that require extra time.
• Working hours: normal shift (8 hours) vs extended shift or weekend work.
• Coordination with warehouse operations: access time to certain zones may be limited.

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4. Time Estimation Simulation for 2,000 m² with 4 Phasing Zones

Here is the simulation we use as an internal reference:

Parameter	Value
Total area	2,000 m²
Number of zones	4 zones @ 500 m²
Productivity per zone	500 m² ÷ 30 m²/day = ± 17 working days
Transition time between zones	2–3 days per zone
Total estimate	(17 + 2.5) × 4 = ± 78 working days (± 3.5 months)

If using 2 parallel teams for different zones, the estimate can drop to 45–55 working days. Important note: this figure does not include permitting time, special material procurement, or extreme weather disruptions.

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5. Time Estimation Comparison: Phasing vs Non-Phasing

Method	Time Estimate	Operational Impact
Non-phasing (simultaneous)	60–70 working days	Warehouse must be completely empty
Phasing 4 zones	75–85 working days	Warehouse remains 70–80% operational
Phasing 6 zones	90–100 working days	More flexible operations, longer duration

Our recommendation: choose phasing if operational losses from a closed warehouse outweigh the additional execution time. For warehouses with high-value goods and fast shipping cycles, phasing is almost always the best choice.

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6. Strategies to Accelerate Execution Without Compromising Quality

PT. Bajaringan Industri Sejahtera applies several acceleration strategies:

• Use high-quality lightweight steel that is precise and easy to install, reducing on-site fabrication time.
• Prefabricate frames in the workshop to reduce assembly time on site.
• Add work teams per zone (e.g., 2 teams for 2 different zones in parallel).
• Optimize material delivery schedules to avoid waiting time.
• Parallel inspections with subsequent work, not sequential.

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7. Delay Risks and Mitigation

Risk	Mitigation
Extreme weather	Provide tarps, schedule roof work during dry season
Material delays	Use trusted vendors and backup stock
Coordination with warehouse	Create mutually agreed zone access schedules
Design changes	Lock the design before the first phase begins

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Conclusion

Renovating a 2,000 m² warehouse roof using the phasing method requires an estimated time of around 75–100 working days, depending on the number of zones and resources used. Although longer than the simultaneous method, phasing provides a major advantage in the form of continued warehouse operations.

PT. Bajaringan Industri Sejahtera is ready to be your partner in warehouse roof renovation with guaranteed lightweight steel material quality, measurable time planning, and an experienced professional team. Contact us for a free consultation and site survey.

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References

• Indonesian National Standard (SNI) 8399:2017 on Specifications for Lightweight Steel Roof Frames.
• Minister of Public Works and Housing Regulation No. 09/PRT/M/2018 on Guidelines for Construction Safety Management Systems.
• Internal data of PT. Bajaringan Industri Sejahtera: Lightweight steel roof installation productivity 2022–2024.
• Journal article: "Time and Cost Analysis of the Phasing Method in Warehouse Renovation Projects" (Journal of Civil Engineering, 2023).
• Interview with the project manager of PT. Bajaringan Industri Sejahtera (2024).