Case study
Promenade Towers Riser Rehabilitation
From a sanitary riser evaluation survey to 70 lined riser stacks in a 1,008-unit cooperative, without a full re-pipe.
Outcomes
70vertical riser stacks lined
- 2pilot stacks, one per tower
- 0full re-pipe needed
- Client
- Promenade Towers cooperative
- Location
- Bethesda, MD
- Scope
- Two 18-story towers, 1,008 units, 70 riser stacks lined
- Duration
- 2021 to 2025
01/ 03
Client Context
- 18
- stories, two towers
- 1,008
- residential units
- 1971
- built
Promenade Towers is a high-rise cooperative of two chevron-shaped towers, built in 1971 as a luxury rental complex with its own market, restaurants, health club and shopping arcade, and converted to a cooperative in 1984.
By 2020 its 50-year-old sanitary drain risers were clogged, corroded and brittle, failing so often that maintenance requests came in daily. The board, general manager and facilities manager went looking for an alternative to an invasive and costly re-pipe.
02/ 03
Strategic Approach
- 01
Riser evaluation survey
In 2021 building management commissioned a Sanitary Riser Evaluation Survey (SRES) to establish the condition of the risers.
- 02
CIPP pilot
The survey led to a CIPP lining pilot on two kitchen riser stacks, one in each tower, completed in the fall of 2021.
- 03
Full rehabilitation
The pilot’s success led to a contract to line the remaining 70 vertical riser stacks in both towers, starting in May 2022.
- 04
Turnkey scope
Kitchen and laundry laterals were re-piped on each floor and every pipe access hole repaired, in a phased, minimally invasive program.
03/ 03
The Poster
The project poster summarises the work: 50-plus-year-old riser infrastructure restored without a full re-pipe, a successful pilot in both towers, and 70 vertical riser stacks lined.
What happens next
Start your project
Tell us more about your infrastructure challenges.
- 01Evaluation studyThe system is mapped, inspected by camera, and every section is condition-graded.
- 02Prioritized findingsGrades are weighted by system risk and turned into a plan, most critical sections first.
- 03RehabilitationTrenchless CIPP lining of the sections that matter most, without full pipe replacement. Access requirements are confirmed during the evaluation.