Case Study Overview
How Rimkus Delivered Construction Administration for Perimeter Fencing, Retaining Wall Replacement, Walkway Rehabilitation, Staircase Reconstruction, Woodshed Installation, and Site Drainage Upgrades at an Occupied Residential Co-operative in Toronto, Ontario
Rimkus Building Sciences provided design, specifications, construction administration, and payment certification for a comprehensive site rehabilitation program at a residential housing co-operative in Toronto, Ontario, delivering 23 field reviews, 14 progress meetings, 6 construction change orders, and 4 payment certificates from mobilization through holdback release for a final contract value of $1,355,541.60 (excl. HST).
A Rimkus Building Sciences engagement delivered full construction administration for a comprehensive 2024 site upgrade program at a residential housing co-operative in Toronto, Ontario: new perimeter and partition fencing, Sienna Stone retaining wall replacement, concrete walkway demolition and reconstruction, cast-in-place staircase rehabilitation, backyard woodshed installation, and site drainage improvements across all four buildings. Rimkus conducted 23 field reviews and 14 progress meetings from June through December 2024, administered 6 construction change orders, issued 4 payment certificates including holdback release, and certified substantial performance under Section 32 of the Ontario Construction Act on April 16, 2025.
Who this is for: Residential housing co-operatives, condominium corporations, non-profit housing providers, and property managers planning comprehensive site rehabilitation programs on occupied residential properties requiring independent construction administration, change order management, payment certification, and substantial performance certification.
What We Did
- Provided construction administration for a comprehensive site upgrade program across four residential buildings: perimeter and partition fencing, Sienna Stone retaining walls, concrete walkway reconstruction, cast-in-place staircase rehabilitation, backyard woodshed installation, and drainage improvements.
- Conducted 23 field reviews from mobilization (June 10, 2024) through substantial completion (December 23, 2024) and facilitated 14 bi-weekly progress meetings from June through December 2024.
- Administered 6 construction change orders covering additional scope and credits, issued 4 payment certificates totaling $1,531,762.01 (incl. HST), and certified substantial performance on April 16, 2025 under Section 32 of the Ontario Construction Act.
How We Helped
- Provided independent oversight of fencing, retaining wall, walkway, and staircase construction across an occupied residential site, maintaining continuous resident access and coordinating tenant communication throughout the program.
- Identified and directed correction of construction deficiencies including fence post alignment, concrete slope corrections, and a disturbed light standard requiring reinstatement, and coordinated resolution of site drainage issues identified during construction.
- Administered $313,300 in additional scope across 4 additive change orders, expanding the program to include woodsheds, additional Sienna Stone stairs, new retaining walls, keyed gate locks, and safety bollards, while returning credits for unused allowances through Change Orders 5 and 6.
|
SERVICE LINES |
SECTOR |
LOCATION |
ENGAGEMENT LEAD |
|---|---|---|---|
|
Building Sciences |
Residential Co-operative / Non-Profit Housing |
Toronto, Ontario |
Marc Winters, P.Eng. — Rimkus BES, Canada |
|
23 |
14 |
6 |
4 |
|---|---|---|---|
|
FIELD REVIEWS |
PROGRESS MEETINGS |
CHANGE ORDERS |
PAYMENT CERTS |
What Was the Challenge? Multi-System Site Rehabilitation at an Occupied Co-operative
A residential housing co-operative in Toronto, Ontario undertook a comprehensive 2024 site upgrade program across four residential buildings. The scope addressed aging site infrastructure that had reached the end of its useful life: deteriorated wood fencing and partition fences between backyards, failing retaining walls, damaged concrete walkways, deteriorated staircases, inadequate backyard storage, and drainage issues including failed catch basins and improper surface slopes.
The program required coordinating multi-trade construction work across an occupied residential site with active tenants, maintaining pedestrian and resident access throughout, coordinating with the City of Toronto on site requirements, and managing a construction program that expanded significantly through six change orders as additional deficiencies and scope items were identified during construction.
Rimkus Building Sciences was engaged to provide construction administration, field reviews, progress meeting management, change order administration, and payment certification for the full program from mobilization through holdback release.
“Comprehensive site rehabilitation at an occupied residential co-operative requires construction administration that keeps residents safe and informed at every stage. On this project, 23 field reviews and 14 progress meetings over six months provided continuous oversight and documented every change, direction, and payment.” – Chander Thusu, B.Eng., BSS, Practice Leader, Building Sciences
How Rimkus Helped: Construction Administration Across a Multi-System Site Program
Rimkus provided the full scope of construction administration services from contractor mobilization through substantial performance certification and holdback release.
Field Reviews and Site Oversight |
Progress Meeting Management |
|---|---|
|
Conducted 23 field reviews from June 10, 2024, through December 23, 2024, documenting construction progress, material installations, and deficiencies across all four buildings and all work areas. Field review reports were distributed to the co-operative and contractor following each visit. |
Facilitated 14 bi-weekly progress meetings from June 19, 2024, through December 16, 2024, coordinating construction sequencing, outstanding action items, resident communications, and contractor direction. Meetings were held on-site and virtually as required. |
Change Order Administration |
Payment Certification |
|
Prepared and administered 6 construction change orders covering unanticipated scope additions, including woodsheds, additional Sienna Stone stairs and retaining walls, cast-in-place staircases, gate locks, and bollards, as well as net-zero scope substitutions and final unused allowance credits. |
Reviewed contractor invoices and issued 4 payment certificates: PC1 (October 9, 2024), PC2 (December 11, 2024), PC3 (March 6, 2025), and PC4 (September 3, 2025). PC4 recommended release of the 10% holdback, subject to confirmation that the 60-day lien period had expired and no liens were registered against the property. |
Substantial Performance Certification |
Occupied-Site Coordination |
|
Certified substantial performance under Section 32 of the Ontario Construction Act on April 16, 2025. The certificate was signed on May 26, 2025, and identified Kabo Construction Inc. as contractor and Rimkus Consulting Group Canada Inc. as payment certifier. |
Field reviews documented contractor adherence to working hours, hoarding requirements, resident access provisions, and tree protection measures throughout the program. Regular progress meetings kept co-operative management informed of construction progress, deficiencies, and outstanding items at every stage. |
Notes on Methods and Limitations
Field reviews are discrete site observations and do not constitute continuous inspection. The contractor remains solely responsible for on-site health and safety, fire hazard management, and compliance with all applicable laws and regulations. Payment certificate amounts are based on work completed to date as observed and confirmed during site reviews; they are recommendations to the owner for payment approval.
Technical Scope: Site Systems Addressed
The 2024 site upgrade program addressed the following systems across all four residential buildings, with Rimkus providing construction administration oversight throughout:
- Perimeter and Partition Fencing: Removal of existing wood fencing and partition fences between backyards; supply and installation of new fencing, partition fences, and gate assemblies across buildings A, B, C, and D. Installation of keyed locks at gate locations with multiple keys per lock set (CO4 and CO5).
- Sienna Stone Retaining Walls: Removal of existing retaining walls and installation of new Sienna Stone concrete unit retaining walls at multiple locations across the property, including service stair retaining walls (CO3) and retaining walls along the fence with the adjacent municipal playground (CO3).
- Concrete Walkway Demolition and Reconstruction: Demolition and removal of damaged concrete walkways at multiple units along the north laneway and courtyard areas (CO2); reconstruction of new concrete walkways maintaining specified drainage slopes; installation of concrete pavers in backyard areas.
- Cast-in-Place Staircase Rehabilitation: Installation of new cast-in-place concrete staircases at backyard entrance units (CO3), new Sienna Stone service stairs between blocks (CO2 and CO3), and aluminum powder-coated railings and guardrails at stair locations (CO2, CO3, CO4). Caulking at stair-building interfaces (CO5).
- Backyard Woodsheds: Supply and installation of 27 new woodsheds with two gates, fenced enclosure, and roof at buildings B and C backyards as per updated project drawings (CO3).
- Drainage Improvements: Installation of new weeping tile connecting to an adjacent catch basin (CO1); new 12-inch by 12-inch PVC catch basins with galvanized grills at backyard locations (CO1); raising of two catch basins between buildings B and C (CO3); cleaning of two catch basins by vacuum truck (CO3); concrete slope corrections at identified pooling locations.
- Timber Curbs and Site Features: Installation of pressure treated 6-inch by 6-inch timber landscaping curbs and retaining walls at building A; concrete entrance improvements and concrete gutter installation (CO1); Bell communications handwell elevation adjustments (CO1).
- Safety Bollards: Supply and installation of 3-foot 6-inch bollards filled with concrete, site-welded for chain links, and painted yellow (CO4).
- Hot Water Tank Exhaust Vents: Installation of new 636 flue exhaust vent systems to facilitate installation of woodshed roofs at two locations (CO4).
- Storm Door Replacement: Supply and installation of new storm door at one unit (CO2).
- Asphalt Patching: New asphalt installation at identified locations including unit frontage areas.
Construction Change Orders
Six construction change orders were administered over the course of the project, expanding the original scope to address additional deficiencies and resident needs identified during construction.
|
Change Order |
Date Issued |
Amount (excl. HST) |
Scope |
|---|---|---|---|
|
CO1 |
July 29, 2024 |
+$27,250 |
Bell handwell elevation correction; new weeping tile and PVC catch basins; timber curbs and retaining wall at Building A; concrete entrance and gutter at guardrail location |
|
CO2 |
September 6, 2024 |
+$84,745 |
North Lane backyard stair railing at Building D; concrete walkway demolition and reconstruction at multiple units; new Sienna Stone staircase at units 44 and 46; storm door replacement at one unit |
|
CO3 |
November 13, 2024 |
+$186,085 |
27 new woodsheds with gates and roofs at Buildings B and C; new Sienna Stone service stair between blocks A and D; new Sienna Stone retaining wall at Building C; two catch basin raises; catch basin cleaning; parging at stair openings; cast-in-place staircases at 7 units; aluminum railings at 2 stair locations |
|
CO4 |
February 18, 2025 |
+$15,320 |
Aluminum railings and guardrails at service stair and 2 backyard stair locations; hot water tank exhaust vents at 2 locations; keyed locks at 2 gate locations with 30 keys; 5 concrete-filled safety bollards painted yellow |
|
CO5 |
May 26, 2025 |
$0.00 (net zero) |
Net-zero change order: credit for one aluminum railing unit (-$1,200.00); additional keyed lock at gate ($400.00); 20 additional keys ($200.00); caulking at 3 stair-building interfaces ($600.00) |
|
CO6 |
September 3, 2025 |
-$100 |
Credit for unused testing and permits allowance from original bid form |
The final contract subtotal was $1,355,541.60 (excl. HST), representing a net addition of $315,291.60, approximately 30% above the original contract amount of $1,040,250.00 (excl. HST). The expansion was driven primarily by Change Order 3, which added the woodshed program, additional staircases, and new retaining walls identified as required after mobilization. All additions were formally documented with itemized scopes and owner-approved pricing before work proceeded.
Payment Certificates
Six construction change orders were administered over the course of the project, expanding the original scope to address additional deficiencies and resident needs identified during construction.
|
Certificate |
Date Issued |
Amount (excl. HST) |
Notes |
|---|---|---|---|
|
PC1 |
October 9, 2024 |
$471,801 |
Recommended payment to Kabo Construction Inc. based on work completed to date; CO1 and CO2 included in contract statement |
|
PC2 |
December 11, 2024 |
$444,286 |
Recommended payment to Kabo Construction Inc.; CO1, CO2, and CO3 included in contract statement |
|
PC3 |
March 6, 2025 |
$462,497 |
Recommended payment to Kabo Construction Inc.; CO1 through CO4 included in contract statement |
|
PC4 |
September 3, 2025 |
$153,176 |
10% holdback release; recommended payment subject to confirmation that 60-day lien period had expired and no liens registered against the property; all 6 COs included |
Key Observations and Corrective Directions
|
Observation |
Direction and Outcome |
|---|---|
|
Fence posts not plumb during installation at units 46 and 48 (FR12) |
Contractor advised to check posts were plumb and centered during installation; Sakrete Rapid Post mix being poured at time of observation; posts confirmed installed correctly |
|
Light standard disturbed by construction activities at Building C backyard (FR23) |
Contractor directed to repair and reinstate light post to original condition; temporary notice posted on light standard; pylons recommended as interim safety measure |
|
Concrete sidewalk pooling at one unit along the north laneway (December 2024 meeting) |
Co-operative and contractor directed to remediate pooling section; full replacement of affected sidewalk section discussed and planned |
|
Existing railing not yet removed at service stair landings (FR23) |
Contractor directed to complete railing removal as part of outstanding items before substantial performance |
|
City of Toronto by-law inquiry regarding concrete pavers at rear unit backyards |
Rimkus followed up with City of Toronto by-law officer; no further direction provided by the City; installation confirmed to proceed as designed |
|
Contractor working hours and resident access |
Regular working hours confirmed as 8am to 6pm Monday to Friday; Saturday work required 48-hour prior notice; hoarding and access routes maintained throughout construction |
Construction Administration Note: Deficiencies on this project were corrected through the documented field review and progress meeting process. Identified issues including fence post alignment, drainage slope corrections, and site safety concerns were formally directed for correction and tracked through the bi-weekly progress meeting record. All issues were resolved before substantial performance was certified.
The Value Delivered
23 field reviews and 14 progress meetings produced a comprehensive construction record. Every phase of the site upgrade program (fencing, retaining walls, walkways, staircases, woodsheds, and drainage) was documented through regular field reviews and bi-weekly progress meetings. The co-operative received an independent account of construction progress, deficiencies, and corrective actions at every stage, separate from the contractor’s own records.
Six change orders transparently administered all scope additions. Additional scope worth $315,291.60 (excl. HST) above the original contract was identified and administered through 6 formal change orders with itemized scope descriptions and approved pricing. Two of those change orders (CO5 and CO6) returned unused credits back to the co-operative, demonstrating transparent administration rather than absorption of unused allowances.
Independent payment certification protected the co-operative’s interests. Four payment certificates were issued over the construction program, each based on independent review of contractor invoices against work verified as complete during field reviews. The holdback release certificate (PC4) included formal conditions protecting the co-operative under the applicable lien holdback requirements.
Substantial performance certified under the Ontario Construction Act. Substantial performance was certified on April 16, 2025 under Section 32 of the Ontario Construction Act, providing the co-operative with the formal documentation required to commence the lien clock for holdback release and completing the construction administration record.
Why Rimkus Built Environment Solutions
Comprehensive site rehabilitation at an occupied residential co-operative requires a construction administrator who understands both the technical requirements of multi-trade civil and site work and the operational constraints of a residential community. Rimkus Building Sciences provides independent field review, change order administration, payment certification, and substantial performance certification that gives co-operatives, non-profit housing providers, and property managers the documented evidence they need: that the work was done to specification, that payments are supported by verified completion, and that scope changes are administered transparently.
We serve residential housing co-operatives, non-profit housing providers, condominium corporations, property managers, and institutional asset managers requiring technical consulting for site rehabilitation, civil upgrades, building envelope assessment, reserve fund studies, and construction administration across residential properties throughout Canada.
Key Takeaways for Residential Co-operatives and Housing Providers
What Every Residential Co-operative and Housing Provider Should Know About Site Rehabilitation Program
- Comprehensive site rehabilitation programs regularly expand in scope once construction begins and existing conditions are exposed. On this project, six change orders added $315,291.60 in scope above the original contract. Independent change order administration means every addition is documented, priced, and owner-approved before work proceeds.
- Independent payment certification protects the co-operative: payments are recommended only when work has been verified as representative of the amount claimed, and holdback release is conditional on confirmed lien period expiry.
- Bi-weekly progress meetings on an occupied residential site are not a formality: they are the mechanism for tracking outstanding items, coordinating tenant communications, directing contractor actions, and maintaining a documented record of every decision made during construction.
- Substantial performance certification under the Ontario Construction Act provides the co-operative with the formal documentation required to start the holdback release clock and close out the construction administration record. • On occupied residential sites, maintaining resident access and clear communication throughout construction is as important as construction quality. Field reviews documenting hoarding, working hours, and access provisions protect residents and give the co-operative a record of contractor compliance.
Related Services
- Building Sciences Consulting
- Site Rehabilitation and Civil Upgrades
- Construction Administration
- Reserve Fund Studies and Condition Assessments
- Specification Writing and Tender Management
Frequently Asked Questions
Connect with Our Expert
Chander Thusu, B.Eng., BSS
Practice Leader, Building Sciences
+1 416 970 3107
[email protected]
View Chander’s Expert Profile
Chander has 32 years of experience in building sciences, structural rehabilitation of parking and balcony structures, and forensic investigation of high-humid buildings such as swimming pools and steam rooms. He holds a Building Science Specialist (BSS) designation from the Ontario Building Envelope Council and a Building Science Certificate from the University of Toronto.
This case study is intended to provide general information and insights into prevailing industry practices. It is not intended to constitute, and should not be relied upon as, legal, technical, or professional advice. The content does not replace consultation with a qualified expert or professional regarding the specific facts and circumstances of any particular matter.