Every aging building maintenance unit reaches a moment where the question shifts from routine repair to something bigger. Owners of buildings 20 to 40 years old often ask whether it makes more sense to refurbish the existing BMU or replace it outright. The answer is rarely obvious, and cost, downtime, code compliance, and parts availability all weigh differently on each side.
This guide breaks down how an OEM assesses that decision. It draws on the experience of Jonathan Lin, RRR Sales Manager for North America at the facade access group, who has spent 17 years working with building maintenance units. The framework is simple. Refurb first. Retrofit next. Replace only when neither can meet the building’s needs.
The industry often collapses BMU work into two categories: fix it or replace it. That framing misses the middle ground where most decisions actually live.
“As a service provider, the priority is to maintain equipment and have it last as long as possible. A proper maintenance program with smartly timed retrofits can extend the life of a BMU for a decade or more. Which is why our group is so aptly named — Refurb, Retrofit, and Replace, in that order.” — Jonathan Lin, RRR Sales Manager for North America
Each tier serves a different purpose:
Replace is the last option. It is reserved for cases where refurb and retrofit can no longer keep the BMU compliant, safe, or fit for purpose.
Before recommending any path, the OEM runs a structured assessment. Two questions drive the process. What is the root cause of the current issues preventing the BMU from working as intended? And where is the unit in its lifecycle?
“When assessing a system, we are mainly looking for two things: the root cause of any issues that are preventing the BMU from working as intended and where a BMU is in its lifecycle. To do so we need to review documentation that shows equipment info, such as Operating and Maintenance manuals as well as assembly and electrical drawings, to understand design and operational intent as well as operational history, such as usage logs and previous inspection reports, to understand the true health and age of the BMU.” — Jonathan Lin
A thorough BMU refurbishment assessment pulls together several data sources. Original O&M manuals establish design intent, drawings reveal how components were meant to work together, and usage logs show how hard the equipment has been worked. Previous inspection and safety compliance reports flag issues that may have gone unaddressed.
The final piece is logistics. Scheduling, budget cycles, and other planned work at the property all shape which path is viable. Even when replacement is the best long-term option, a refurbishment or targeted retrofit may serve as a stopgap while funding and planning fall into place.
Some scenarios remove the option to refurb or retrofit. Recognizing them early saves owners from spending capital on work that will not solve the underlying problem.
Structural issues top the list. When corrosion has compromised the steel structure of the BMU, no electrical or mechanical upgrade addresses the root problem.
“We have an account in Miami where the BMU was from an era where only the outside of the steel was being galvanized and due to exposure to the salty air, continued corrosion was unavoidable and replacement was required.” — Jonathan Lin
Missing information is another trigger. Without documentation showing how a BMU was built and how it has performed, no reliable diagnosis is possible. Unavailable parts push the same direction, since sourcing spares becomes unpredictable and expensive when the OEM no longer supports a legacy platform.
Code and building changes finish the list. If a facade has been re-clad, extended, or fitted with new architectural features, the original BMU may no longer reach every elevation. Local code updates can also render an older machine non-compliant even if it still runs. In these situations, a full building maintenance unit replacement is the only path that meets the building’s actual requirements.
The practical differences between refurbishment and replacement come down to time on site, cost exposure, and how each option fits within the building’s operational calendar.
“Refurbs typically take months while a replacement will take over a year to complete. If timed correctly, most refurbs can be completed during the offseason to minimize or eliminate downtime.” — Jonathan Lin
The timeline difference matters more than raw cost in many cases. A refurb scheduled around the building’s offseason often produces no visible impact on tenants or operations. A replacement requires roof access for demolition, structural verification, delivery of new components, installation, and commissioning. That process runs quarters, not weeks.
Cost varies by scope, but a well-designed refurb or retrofit typically lands at a fraction of a full BMU replacement. Phasing the work also helps facility teams secure funding across multiple budget cycles rather than fighting for one large capital approval.
“We recently took over a service account in San Francisco where a competitor could not keep a Mannesmann that was installed in 1985 running and told the customer it was at the end of its life and had to be replaced. The customer reached back out to us and as the OEM we were able to propose a refurb as well as suggest some preventative maintenance items that the competitor did not consider. By presenting our suggestions in a phased manner, the customer was able to secure funding for all of this work.” — Jonathan Lin
Age is a significant factor. The more operating hours a BMU accumulates, the more attention it needs. Lifecycle management can preplan major refurbishments and BMU upgrades in phases, but only up to the point where parts and subassemblies remain available.
Downtime is a major concern for owners, and North America has seen a strong push for facilities to maintain a spare parts cache. Holding critical components on site helps minimize disruption and buys time to plan a modernization strategy when older parts become harder to source. The FAS OEM spare parts program supports this approach with genuine components engineered to the original specification.
“Age is a major factor as the hours add up on equipment. The more TLC a BMU will require. We can work with a client on lifecycle management and preplan major refurbs and retrofits in phases, but at some point that is no longer an option as parts and subassemblies become obsolete.” — Jonathan Lin
Many owners arrive at the replacement conversation because a service provider has told them the current unit has reached the end of its life. That diagnosis is often correct, but it is also frequently wrong when the provider lacks OEM access to drawings, historical data, and engineering support.
“As the industry leading OEM and service provider, we have the resources and experience that others do not to be able to properly diagnose root problems and provide a modernization or upgrade solution that is a fraction of the cost of a replacement and can prolong the life of a BMU for another decade or more.” — Jonathan Lin
This is where the value of asset management from the original manufacturer becomes clear. Access to engineering records, retained knowledge of design intent, and a supply chain of certified parts change what is possible on an aging BMU.
BMU refurbishment vs. full replacement is rarely a one-answer question. The right path depends on structural condition, documentation, parts availability, code compliance, and the building’s operational calendar. Working through those variables with an OEM that has designed, built, and serviced the equipment produces the most reliable recommendation.
For most owners, refurbishment or a well-scoped retrofit will meet the need at a fraction of the cost and downtime of a full replacement. Replacement remains the right call when structural issues, missing documentation, or code changes leave no other viable option. FAS supports both paths through a global service network. To explore what is possible for your building, get in touch with the FAS service solutions team.
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ContactBMU stands for Building Maintenance Unit. In facade cleaning, it refers to the permanent access system installed on a building, typically on the roof, that carries workers and equipment along the exterior for cleaning, inspection, and repair. A BMU replaces the need for scaffolding or rope access on tall buildings and gives crews a stable, engineered platform to reach every elevation of the facade.
BMU stands for Building Maintenance Unit. The term is used across the facade access industry to describe the roof-mounted machine that provides access to a building’s exterior for maintenance work. A building maintenance unit system typically includes a base structure, a jib or boom, a suspended cradle, and the hoist and control systems that move workers along the facade.
In construction, BMU refers to the Building Maintenance Unit specified during the design and engineering phase of a project. Architects and facade consultants coordinate with BMU manufacturers to integrate the access system into the building structure. Roof loads, track layouts, anchoring points, and parking positions all need to be planned before construction, which is why the BMU is treated as a structural and architectural consideration, not an afterthought.
In architecture, refurbishment means restoring an existing building or system to functional condition without replacing it entirely. Applied to facade access, BMU refurbishment restores the original equipment to reliable operation through targeted repairs, component replacement, and preventative maintenance. FAS refurbishment solutions cover both cosmetic and mechanical restoration, extending the working life of the BMU while preserving the original design intent.
BMU work is governed by a range of international and regional standards. EN 1808 sets safety requirements for suspended access equipment across Europe. ASME A120.1 governs powered platforms in the United States, and OSHA 1910.66 provides the federal regulatory framework. Canada follows CAN/CSA-Z271. Australia uses AS 1418.13 and AS/NZS 2550.13. Any refurbishment or replacement should bring the BMU into compliance with the standards in force at the property. FAS publishes a detailed overview of applicable codes, regulations, and standards for reference.
Inspection frequency depends on jurisdiction, but most codes require at least an annual thorough examination by a qualified inspector. Operators should also complete routine daily checks before and after using the equipment, while a pre-use inspection to certify the BMU for use must be completed by a competent worker. EN 1808 and ASME A120.1 both specify inspection intervals, and many owners run more frequent inspections as part of an ongoing BMU maintenance program. Regular inspections also feed the historical record that informs future refurb or replacement decisions.