No. The Sherpa drone is operated by a trained pilot and does not currently support autonomous flight outside of its failsafe functions. Assisted hover, collision sensing and automated landing features help the pilot, but the pilot must maintain control and visual line of sight.
A working setup may include a pump, hoses, a water tank or site connection, chemicals, filtration or water purification, supporting plumbing and a generator when using the Power Tether.
Existing cleaning companies may be able to use some of the infrastructure they already own. Open trailer, enclosed trailer, van and truck-bed systems are also available through a Lucid Bots partner.
For soft washing, the Sherpa drone supports flow rates up to 12 GPM at 300 PSI. High-pressure configurations support pressure up to 4,500 PSI and flow up to 10 GPM.
The right combination of pressure, flow, chemistry and nozzle depends on the surface and cleaning method.
No. The Sherpa drone is strongest on repeatable maintenance work where water, chemistry and controlled spray can do most of the cleaning. Heavy restoration, etched glass, efflorescence, graffiti and work requiring physical agitation may require another method.
A test panel can help determine the right chemistry, process and equipment before the full job is quoted.
No. Submitting the form starts a review with our Sales Engineering team. We will recommend the most appropriate available option based on your application, location, project, timing, and stage of evaluation.
Potentially. On-site demonstrations are reserved for qualified opportunities and suitable sites.
Before recommending an on-site demonstration, we may ask about the property, building height, surface, water access, operating environment, project value, timing, and other logistical considerations.
Costs vary by format. Regional events and the Charlotte experiences are offered without a demonstration fee, while private on-site demonstrations may involve a fee, travel expenses, or other requirements. Any cost will be explained before you commit to a demonstration.
Yes. Tell us candidly where you are in the process and what you need to understand. Depending on your readiness and location, we may recommend a regional event or Charlotte experience before considering a private on-site demonstration.
No. A demo helps you evaluate the technology and operating fit. A quote is the better path when you are ready to discuss the Sherpa configuration, pricing, financing, and purchase process.
Not for Exterior Cleaning 101 or In-Person Sherpa Training at Lucid Bots headquarters. Training aircraft and related equipment are provided for the hands-on facility program. First Job Consultation requires the customer's own Sherpa drone and compatible job-ready equipment.
In-Person Sherpa Training is dedicated hands-on aircraft instruction at Lucid Bots headquarters. Exterior Cleaning 101 includes Sherpa drone instruction and flight training within a broader three-day exterior-cleaning program. First Job Consultation adds coaching during an approved live commercial deployment.
No. FAA Part 107 Exam Prep helps a learner study aviation rules and knowledge areas for the FAA test. Sherpa Academy teaches the setup, operation, care, and jobsite use of the Sherpa drone. Many new operators need both, but they solve different training needs.
In the United States, each operation conducted under Part 107 must have a remote pilot in command who holds an FAA Remote Pilot Certificate and meets the FAA's aeronautical-knowledge recency requirements. A person without a certificate may manipulate the controls only under the direct supervision of a certificated remote pilot in command who can immediately take control. The aircraft must also be properly registered and operated in compliance with applicable Remote ID, airspace, operating, and waiver requirements. Sherpa Academy is a Lucid Bots training and warranty requirement; it does not replace FAA certification.
No. You can begin FAA Part 107 Exam Prep, Sherpa Academy, or Exterior Cleaning 101 without prior flight experience. New pilots should expect to build competence in stages through study, supervised practice, and appropriately scoped work.
Every project requires a cleaning crew, hoses, equipment, and a controlled work area. However, drone cleaning can reduce the need for lifts, scaffolding, and rope-access crews. The provider will coordinate the work around the building and its occupants.
Submit the building anyway. Many providers travel for qualified projects, and the nearest operator may serve a larger region than the map shows.
Drone cleaning may be suitable for offices, hotels, multifamily properties, hospitals, warehouses, campuses, and other commercial buildings. The surrounding flight area, building geometry, surface condition, and requested service must still be evaluated.
Drone cleaning is often less expensive than traditional high-access methods because crews can complete the work faster and avoid the cost, setup, and rental of lifts, scaffolding, or rope-access systems.
The published configuration calls for approximately 130 to 160 PSI at 1.8 GPM and a 1/4-inch connection. The ground rig listed with the payload includes a 25-gallon tank, pump, reel, and hose.
Yes, by closing the pores, dirt and contaminants sit on top of the concrete instead of penetrating it, making future cleaning faster, easier, and less frequent.
Surface must be dry prior to application. Excessive moisture inhibits penetration and reduces the service life and performance of the treatment. The current documented workflow recommends waiting at least 24 hours after cleaning, with additional drying time for porous surfaces or unfavorable conditions.
No. A penetrating water repellent enters below the surface of the substrate rather than forming a film on the surface, so it behaves differently from paint or a film-forming coating. Durability still depends on the treatment, substrate, application quality, pressure used during future cleaning, and environmental exposure.
Yes. The surface should be clean, dry, and free of dirt, residue, existing films, or incompatible treatments. Complete a test area and follow the selected treatment’s preparation and curing requirements.
Shield Payload is not positioned as a precision painting solution. Its current purpose is controlled application of validated water-based repellents and compatible protective treatments.
The strongest publicly documented combination is PROSOCO Siloxane WB Concentrate. Other water-based silane or siloxane treatments may be compatible after review, but every material must be evaluated against its TDS, SDS, viscosity, substrate requirements, and cleanup instructions.
Shield Payload is intended primarily for qualified porous concrete and masonry. Final compatibility comes from the selected treatment, not the payload alone, so every substrate should be reviewed and tested before full application. Check product data sheet for substrate compatibility before applying.
Commercial Sherpa drone operators in the United States need an FAA Part 107 Remote Pilot Certificate. Previous drone experience is not required, but operators must complete the appropriate certification before performing commercial work.
There is no universal production rate. Building design, surface condition, chemistry, water supply, weather, and job setup all affect speed. The biggest advantage is often significantly reducing the time required to set up and reposition lifts, scaffolding, or rope-access systems.
The Sherpa drone can legally fly up to 180 feet in supported configurations. Actual working height depends on the payload, hose, liquid weight, wind, site conditions, and applicable flight restrictions.
It can, when the right cleaning method, chemistry, pressure, and water quality are used. The Sherpa drone changes how the cleaning solution reaches the surface, not the science behind the cleaning.
The Sherpa drone's default configuration is optimized for exterior soft washing. The Window Payload adds commercial window cleaning, while the Shield Payload supports water repellents and coating applications. Job fit depends on the surface, buildup, and desired result.
The Sherpa drone carries the spray system while water and cleaning solution travel through a lightweight hose from a ground rig. The pilot controls the drone from the ground and applies the same water, chemistry, and cleaning methods used in professional exterior cleaning.
The published starting point is 1 part Lucid Clear+ to 50 parts water. Actual metering depends on the pump, injector, metering component, hose length, and nozzle. Do not use Lucid Clear+ at a stronger concentration than its current instructions allow.
Lucid Clear+ is the primary publicly documented solution for Window Payload. Any alternative chemistry should be reviewed for glass compatibility, dilution, handling, rinsing, and equipment compatibility before use.
Existing mineral deposits often require specialized chemistry, agitation, or restoration. Window Payload should not be positioned as a universal hard-water-stain removal system.
Window Payload is intended primarily for routine exterior commercial windows and glazed facades. Coated glass, films, damaged seals, specialty glazing, and adjacent materials should be reviewed before cleaning. Complete a test area when compatibility is uncertain.
No cleaning method should make that guarantee without qualifying the glass, water, chemistry, weather, and process. Properly purified water, correct dilution, appropriate dwell time, and thorough rinsing support a cleaner finish with minimal spotting.
No. Window Payload is a touchless spray system and does not include a brush or squeegee. Some heavily soiled or mineral-stained glass may still require contact cleaning or restoration.
No. The current manual prohibits operation in rain, snow, or fog. Keep the generator and ground unit dry and away from spray-back and runoff. Suspend operations when lightning is present or approaching.
Use a generator capable of at least 10,000 running watts with a 240V, 50A-capable connection. Lucid Bots validated the system using a Predator 13,000-watt Tri-Fuel generator.
The supplied power tether is 200 feet long. The entire cable must be fully unspooled during every operation, even when the Sherpa drone is working at a lower height.
Lucid Bots has demonstrated a stable maximum of approximately 140 feet AGL with spray active, wind below 10 mph, and a lightweight 1/4-inch hose. Actual working height may be substantially lower in heavier hose or filled Window Payload configurations.
It removes the normal battery-cycle limit, but it does not remove every operating limit. Flight duration still depends on generator fuel, crew endurance, weather, equipment condition, inspections, site schedules, water or treatment supply, and regulatory requirements.
Both sections are part of the National Defense Authorization Act (NDAA), but they cover different areas. Section 848 focuses on unmanned aircraft systems (UAS) and the sourcing of critical drone components. Section 889 focuses on telecommunications and surveillance equipment, restricting the use of certain covered manufacturers.
In simple terms: Section 848 applies to the drone itself, while Section 889 applies to the communications and surveillance technology used within the system.
The operator retains full manual control of the Sherpa Drone at all times. If GPS is lost, the drone maintains position using its failsafe systems. If radio contact is lost, the drone will hover for 60 seconds then initiate a controlled vertical descent straight down from its current position.
The Sherpa Drone applies standard commercial soft-wash chemistry, sodium hypochlorite and surfactant, used by commercial cleaning contractors across the industry.
Yes, with appropriate approvals in place. Drone operations on military installations require coordination with the installation's airspace authority. The Sherpa 1.5 NDAA UAS meets NDAA Section 889 compliance requirements.
The Sherpa Drone's onboard camera is used for operator situational awareness and flight control only. The drone does not store footage on external servers, transmit imagery to third parties, or perform mapping, reconnaissance, or area scanning.
No. The Sherpa NDAA UAS is a distinct configuration with a fully audited Bill of Materials verified to contain zero components from NDAA-prohibited manufacturers. If you are working at a government or military facility, confirm your operator owns the Sherpa NDAA UAS drone specifically, not the standard Sherpa drone.
The Sherpa drone does not replace soft washing or pressure washing as cleaning methods. It changes how water, pressure and chemistry reach the surface. On suitable high-access jobs, crews can reduce their reliance on lifts, scaffolding and rope access while using familiar cleaning processes.
Traditional methods may still be better for flatwork, detailed restoration, tight spaces or surfaces that require brushing, scraping or agitation.
No prior drone experience is required. Lucid Bots provides Sherpa Academy, an online training course, which can be completed at your own pace. We also offer a three day in-person training course for an additional fee. You will need an FAA Part 107 certification for commercial use.
The Sherpa drone works with many commercial soft-wash and high-pressure pumps. Compatibility depends on the payload, pressure, flow, hose and nozzle.
The Lucid Bots team can review your current system or recommend a compatible setup for the work you want to perform.
Battery-powered flight time is up to 19 minutes per cycle. Actual flight time depends on the payload, hose, wind, battery condition and operating environment.
For longer jobs, the optional Power Tether draws electricity from a compatible ground generator to support continuous operation without routine battery swaps. Lucid Bots has tested more than 8 hours of continuous tethered flight, with an onboard backup battery providing power for a safe landing if ground power is interrupted.
No. The Sherpa drone is operated by a trained pilot and does not currently support autonomous flight outside of its failsafe functions. Assisted hover, collision sensing and automated landing features help the pilot, but the pilot must maintain control and visual line of sight.
A working setup may include a pump, hoses, a water tank or site connection, chemicals, filtration or water purification, supporting plumbing and a generator when using the Power Tether.
Existing cleaning companies may be able to use some of the infrastructure they already own. Open trailer, enclosed trailer, van and truck-bed systems are also available through a Lucid Bots partner.
For soft washing, the Sherpa drone supports flow rates up to 12 GPM at 300 PSI. High-pressure configurations support pressure up to 4,500 PSI and flow up to 10 GPM.
The right combination of pressure, flow, chemistry and nozzle depends on the surface and cleaning method.
No. The Sherpa drone is strongest on repeatable maintenance work where water, chemistry and controlled spray can do most of the cleaning. Heavy restoration, etched glass, efflorescence, graffiti and work requiring physical agitation may require another method.
A test panel can help determine the right chemistry, process and equipment before the full job is quoted.
Equipped with the Window Payload, the Sherpa drone carries cleaning solution in an onboard tank and receives water from the ground. The operator can apply solution, rinse with deionized water, and repeat as needed while piloting from the ground.
The Sherpa drone does not replace soft washing or pressure washing as cleaning methods. It changes how water, pressure and chemistry reach the surface. On suitable high-access jobs, crews can reduce their reliance on lifts, scaffolding and rope access while using familiar cleaning processes.
Traditional methods may still be better for flatwork, detailed restoration, tight spaces or surfaces that require brushing, scraping or agitation.
No prior drone experience is required. Lucid Bots provides Sherpa Academy, an online training course, which can be completed at your own pace. We also offer a three day in-person training course for an additional fee. You will need an FAA Part 107 certification for commercial use.
The Sherpa drone works with many commercial soft-wash and high-pressure pumps. Compatibility depends on the payload, pressure, flow, hose and nozzle.
The Lucid Bots team can review your current system or recommend a compatible setup for the work you want to perform.
Battery-powered flight time is up to 19 minutes per cycle. Actual flight time depends on the payload, hose, wind, battery condition and operating environment.
For longer jobs, the optional Power Tether draws electricity from a compatible ground generator to support continuous operation without routine battery swaps. Lucid Bots has tested more than 8 hours of continuous tethered flight, with an onboard backup battery providing power for a safe landing if ground power is interrupted.
Commercial Sherpa drone operators in the United States need an FAA Part 107 Remote Pilot Certificate. Previous drone experience is not required, but operators must complete the appropriate certification before performing commercial work.
There is no universal production rate. Building design, surface condition, chemistry, water supply, weather, and job setup all affect speed. The biggest advantage is often significantly reducing the time required to set up and reposition lifts, scaffolding, or rope-access systems.
The Sherpa drone can legally fly up to 180 feet in supported configurations. Actual working height depends on the payload, hose, liquid weight, wind, site conditions, and applicable flight restrictions.
It can, when the right cleaning method, chemistry, pressure, and water quality are used. The Sherpa drone changes how the cleaning solution reaches the surface, not the science behind the cleaning.
The Sherpa drone's default configuration is optimized for exterior soft washing. The Window Payload adds commercial window cleaning, while the Shield Payload supports water repellents and coating applications. Job fit depends on the surface, buildup, and desired result.
The Sherpa drone carries the spray system while water and cleaning solution travel through a lightweight hose from a ground rig. The pilot controls the drone from the ground and applies the same water, chemistry, and cleaning methods used in professional exterior cleaning.
Both sections are part of the National Defense Authorization Act (NDAA), but they cover different areas. Section 848 focuses on unmanned aircraft systems (UAS) and the sourcing of critical drone components. Section 889 focuses on telecommunications and surveillance equipment, restricting the use of certain covered manufacturers.
In simple terms: Section 848 applies to the drone itself, while Section 889 applies to the communications and surveillance technology used within the system.
The operator retains full manual control of the Sherpa Drone at all times. If GPS is lost, the drone maintains position using its failsafe systems. If radio contact is lost, the drone will hover for 60 seconds then initiate a controlled vertical descent straight down from its current position.
The Sherpa Drone applies standard commercial soft-wash chemistry, sodium hypochlorite and surfactant, used by commercial cleaning contractors across the industry.
Yes, with appropriate approvals in place. Drone operations on military installations require coordination with the installation's airspace authority. The Sherpa 1.5 NDAA UAS meets NDAA Section 889 compliance requirements.
The Sherpa Drone's onboard camera is used for operator situational awareness and flight control only. The drone does not store footage on external servers, transmit imagery to third parties, or perform mapping, reconnaissance, or area scanning.
No. The Sherpa NDAA UAS is a distinct configuration with a fully audited Bill of Materials verified to contain zero components from NDAA-prohibited manufacturers. If you are working at a government or military facility, confirm your operator owns the Sherpa NDAA UAS drone specifically, not the standard Sherpa drone.
The published configuration calls for approximately 130 to 160 PSI at 1.8 GPM and a 1/4-inch connection. The ground rig listed with the payload includes a 25-gallon tank, pump, reel, and hose.
Yes, by closing the pores, dirt and contaminants sit on top of the concrete instead of penetrating it, making future cleaning faster, easier, and less frequent.
Surface must be dry prior to application. Excessive moisture inhibits penetration and reduces the service life and performance of the treatment. The current documented workflow recommends waiting at least 24 hours after cleaning, with additional drying time for porous surfaces or unfavorable conditions.
No. A penetrating water repellent enters below the surface of the substrate rather than forming a film on the surface, so it behaves differently from paint or a film-forming coating. Durability still depends on the treatment, substrate, application quality, pressure used during future cleaning, and environmental exposure.
Yes. The surface should be clean, dry, and free of dirt, residue, existing films, or incompatible treatments. Complete a test area and follow the selected treatment’s preparation and curing requirements.
Shield Payload is not positioned as a precision painting solution. Its current purpose is controlled application of validated water-based repellents and compatible protective treatments.
The strongest publicly documented combination is PROSOCO Siloxane WB Concentrate. Other water-based silane or siloxane treatments may be compatible after review, but every material must be evaluated against its TDS, SDS, viscosity, substrate requirements, and cleanup instructions.
Shield Payload is intended primarily for qualified porous concrete and masonry. Final compatibility comes from the selected treatment, not the payload alone, so every substrate should be reviewed and tested before full application. Check product data sheet for substrate compatibility before applying.
The published starting point is 1 part Lucid Clear+ to 50 parts water. Actual metering depends on the pump, injector, metering component, hose length, and nozzle. Do not use Lucid Clear+ at a stronger concentration than its current instructions allow.
Lucid Clear+ is the primary publicly documented solution for Window Payload. Any alternative chemistry should be reviewed for glass compatibility, dilution, handling, rinsing, and equipment compatibility before use.
Existing mineral deposits often require specialized chemistry, agitation, or restoration. Window Payload should not be positioned as a universal hard-water-stain removal system.
Window Payload is intended primarily for routine exterior commercial windows and glazed facades. Coated glass, films, damaged seals, specialty glazing, and adjacent materials should be reviewed before cleaning. Complete a test area when compatibility is uncertain.
No cleaning method should make that guarantee without qualifying the glass, water, chemistry, weather, and process. Properly purified water, correct dilution, appropriate dwell time, and thorough rinsing support a cleaner finish with minimal spotting.
No. Window Payload is a touchless spray system and does not include a brush or squeegee. Some heavily soiled or mineral-stained glass may still require contact cleaning or restoration.
No. The current manual prohibits operation in rain, snow, or fog. Keep the generator and ground unit dry and away from spray-back and runoff. Suspend operations when lightning is present or approaching.
Use a generator capable of at least 10,000 running watts with a 240V, 50A-capable connection. Lucid Bots validated the system using a Predator 13,000-watt Tri-Fuel generator.
The supplied power tether is 200 feet long. The entire cable must be fully unspooled during every operation, even when the Sherpa drone is working at a lower height.
Lucid Bots has demonstrated a stable maximum of approximately 140 feet AGL with spray active, wind below 10 mph, and a lightweight 1/4-inch hose. Actual working height may be substantially lower in heavier hose or filled Window Payload configurations.
It removes the normal battery-cycle limit, but it does not remove every operating limit. Flight duration still depends on generator fuel, crew endurance, weather, equipment condition, inspections, site schedules, water or treatment supply, and regulatory requirements.
Every project requires a cleaning crew, hoses, equipment, and a controlled work area. However, drone cleaning can reduce the need for lifts, scaffolding, and rope-access crews. The provider will coordinate the work around the building and its occupants.
Submit the building anyway. Many providers travel for qualified projects, and the nearest operator may serve a larger region than the map shows.
Drone cleaning may be suitable for offices, hotels, multifamily properties, hospitals, warehouses, campuses, and other commercial buildings. The surrounding flight area, building geometry, surface condition, and requested service must still be evaluated.
Drone cleaning is often less expensive than traditional high-access methods because crews can complete the work faster and avoid the cost, setup, and rental of lifts, scaffolding, or rope-access systems.
No. Submitting the form starts a review with our Sales Engineering team. We will recommend the most appropriate available option based on your application, location, project, timing, and stage of evaluation.
Potentially. On-site demonstrations are reserved for qualified opportunities and suitable sites.
Before recommending an on-site demonstration, we may ask about the property, building height, surface, water access, operating environment, project value, timing, and other logistical considerations.
Costs vary by format. Regional events and the Charlotte experiences are offered without a demonstration fee, while private on-site demonstrations may involve a fee, travel expenses, or other requirements. Any cost will be explained before you commit to a demonstration.
Yes. Tell us candidly where you are in the process and what you need to understand. Depending on your readiness and location, we may recommend a regional event or Charlotte experience before considering a private on-site demonstration.
No. A demo helps you evaluate the technology and operating fit. A quote is the better path when you are ready to discuss the Sherpa configuration, pricing, financing, and purchase process.
Not for Exterior Cleaning 101 or In-Person Sherpa Training at Lucid Bots headquarters. Training aircraft and related equipment are provided for the hands-on facility program. First Job Consultation requires the customer's own Sherpa drone and compatible job-ready equipment.
In-Person Sherpa Training is dedicated hands-on aircraft instruction at Lucid Bots headquarters. Exterior Cleaning 101 includes Sherpa drone instruction and flight training within a broader three-day exterior-cleaning program. First Job Consultation adds coaching during an approved live commercial deployment.
No. FAA Part 107 Exam Prep helps a learner study aviation rules and knowledge areas for the FAA test. Sherpa Academy teaches the setup, operation, care, and jobsite use of the Sherpa drone. Many new operators need both, but they solve different training needs.
In the United States, each operation conducted under Part 107 must have a remote pilot in command who holds an FAA Remote Pilot Certificate and meets the FAA's aeronautical-knowledge recency requirements. A person without a certificate may manipulate the controls only under the direct supervision of a certificated remote pilot in command who can immediately take control. The aircraft must also be properly registered and operated in compliance with applicable Remote ID, airspace, operating, and waiver requirements. Sherpa Academy is a Lucid Bots training and warranty requirement; it does not replace FAA certification.
No. You can begin FAA Part 107 Exam Prep, Sherpa Academy, or Exterior Cleaning 101 without prior flight experience. New pilots should expect to build competence in stages through study, supervised practice, and appropriately scoped work.
No. The Sherpa drone is operated by a trained pilot and does not currently support autonomous flight outside of its failsafe functions. Assisted hover, collision sensing and automated landing features help the pilot, but the pilot must maintain control and visual line of sight.
A working setup may include a pump, hoses, a water tank or site connection, chemicals, filtration or water purification, supporting plumbing and a generator when using the Power Tether.
Existing cleaning companies may be able to use some of the infrastructure they already own. Open trailer, enclosed trailer, van and truck-bed systems are also available through a Lucid Bots partner.
For soft washing, the Sherpa drone supports flow rates up to 12 GPM at 300 PSI. High-pressure configurations support pressure up to 4,500 PSI and flow up to 10 GPM.
The right combination of pressure, flow, chemistry and nozzle depends on the surface and cleaning method.
No. The Sherpa drone is strongest on repeatable maintenance work where water, chemistry and controlled spray can do most of the cleaning. Heavy restoration, etched glass, efflorescence, graffiti and work requiring physical agitation may require another method.
A test panel can help determine the right chemistry, process and equipment before the full job is quoted.
Equipped with the Window Payload, the Sherpa drone carries cleaning solution in an onboard tank and receives water from the ground. The operator can apply solution, rinse with deionized water, and repeat as needed while piloting from the ground.
The Sherpa drone does not replace soft washing or pressure washing as cleaning methods. It changes how water, pressure and chemistry reach the surface. On suitable high-access jobs, crews can reduce their reliance on lifts, scaffolding and rope access while using familiar cleaning processes.
Traditional methods may still be better for flatwork, detailed restoration, tight spaces or surfaces that require brushing, scraping or agitation.
No prior drone experience is required. Lucid Bots provides Sherpa Academy, an online training course, which can be completed at your own pace. We also offer a three day in-person training course for an additional fee. You will need an FAA Part 107 certification for commercial use.
The Sherpa drone works with many commercial soft-wash and high-pressure pumps. Compatibility depends on the payload, pressure, flow, hose and nozzle.
The Lucid Bots team can review your current system or recommend a compatible setup for the work you want to perform.
Battery-powered flight time is up to 19 minutes per cycle. Actual flight time depends on the payload, hose, wind, battery condition and operating environment.
For longer jobs, the optional Power Tether draws electricity from a compatible ground generator to support continuous operation without routine battery swaps. Lucid Bots has tested more than 8 hours of continuous tethered flight, with an onboard backup battery providing power for a safe landing if ground power is interrupted.
Lucid Bots is a Charlotte, North Carolina-based robotics company that builds commercial cleaning drones to take on dull, dirty, and dangerous exterior maintenance work.