How Drawing Review Caught Stack Errors on Portland Apartments
- Three Portland apartment buildings shared unit types whose waste stacks missed the structural openings above the podium.
- Helonic checked the repeating stacks on the PDF sets and counted every floor that copied the miss.
- The contractor confirmed 780 issues and priced $260,000 in stack coring before permit.
Portland, OR. 780 issues on 3 buildings.
Issues Detected
780 on 3 buildings
Stack Misses
96 waste and vent
Estimated Savings
$260K before permit
96 Stack Misses on Three Portland Apartment Sets
A general contractor was pricing three apartment buildings in Portland. The units were wood over a concrete podium. A stack that misses the opening has to be cored.
Waste and vent stacks on the plumbing sheets missed the slab openings on the podium for two unit types. The miss repeated on every floor above. Wall tags and energy notes were in the set. They were not the $260,000.
The miss repeated every floor above the podium, so the count was the unit type times the stories.
Helonic Counted 96 Stack Misses Above the Podium
They uploaded the three PDF sets. Helonic lined the plumbing stacks up with the structural openings.
The list was 780 issues. The ones that cost money were 96 stack misses. Code notes were the rest of the list.
Each stack miss named the unit type and the floors that copied it.
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780 Issues, $260,000 Kept Off the Permit Set
The design team moved the two stacks and picked one assembly number for the corridor before the permit sets went out.
They estimated $260,000 to core the podium after the slab was poured.
Permit comments asked for a site-access dimension. The stacks were already corrected.
“Above a podium, a stack either hits the opening or it doesn't. Helonic found 96 misses across three Portland buildings before we bought the set.”
Frequently asked questions
What cost money on these apartments?
96 waste and vent stacks that missed the podium openings. Code notes were on the list. Coring the slab was the change order.
How is this different from the mixed-use contractor story?
That page is one Bay Area tower. This one is three Portland apartment buildings checked before permit.
Where did the 96 stack misses come from?
A completed Helonic review of three Portland apartment sets.
Did one fix cover every floor?
Yes for the two unit types. After the typical stack moved, the copied floors used the same opening.
Milind Sagaram
Co-founder & CEO, HelonicMilind is the co-founder and CEO of Helonic, where he leads product and go-to-market for AI-powered construction drawing analysis. He works closely with general contractors, project managers, estimators, and owners to understand how drawing quality drives project outcomes - and where AI can reduce RFIs, change orders, and rework. Milind has interviewed hundreds of construction professionals across project delivery roles, from preconstruction estimators at ENR top-400 contractors to facilities directors at institutional owners, and uses those conversations to shape both product direction and the way Helonic talks about the work.
- Construction project delivery and preconstruction
- RFI and change order economics
- Owner and GC workflows for drawing QA/QC
- Estimating risk and bid-stage scope assessment
How this page was researched: Reviewed against Helonic's 2026 drawing-analysis categories, RFI workflow, and product capabilities.
Last reviewed by Milind Sagaram · September 21, 2026