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
Three Podium Apartment Buildings Where 2 Unit Types Missed the Slab Openings
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.
See multifamily drawing review, Oregon plan review requirements, mid-rise wood frame coordination, how multifamily drawing sets get reviewed, stacking analysis, and the Seattle apartment review.
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.
A stack that misses a podium opening is a plumbing and structural conflict. Across 1,000+ drawing packages Helonic has reviewed, about 8 in 10 had at least one coordination conflict between disciplines. See what Helonic found across 1,000+ drawing reviews.
Oregon Specialty Codes and the Podium Slab Under 96 Stack Misses
Oregon uses statewide specialty codes. Buildings are permitted under the Oregon Structural Specialty Code, based on the International Building Code, and plumbing under the Oregon Plumbing Specialty Code, based on the Uniform Plumbing Code. Portland enforces both.
Wood over a concrete podium relies on an IBC provision that treats the podium and the floors above as separate buildings for construction type. The podium slab is a rated horizontal separation, so every stack through it needs a planned opening and a tested firestop system.
That makes a missed opening expensive. Coring a podium slab after the pour means scanning for reinforcing, an engineer's sign-off, and new firestopping at each hole. The contractor put that at $260,000.
Oregon also enforces its own energy code, the Oregon Energy Efficiency Specialty Code, which is where the energy notes on this set came from. Those notes were on the list. They were not the coring.
“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.”
Portland Apartment Drawing Review: Questions and Answers
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.
What building code applies in Portland, Oregon?
The Oregon Structural Specialty Code, based on the International Building Code, with plumbing under the Oregon Plumbing Specialty Code. Oregon adopts these statewide and Portland enforces them.
Why is a podium slab hard to fix after the pour?
It is a rated separation between the concrete podium and the wood floors above. A stack that misses its opening has to be cored, scanned, approved by the engineer, and firestopped.
What else was on the 780-issue list?
Wall tags, energy notes, and other code notes. The contractor priced the 96 stack misses because those were the coring. The rest were drawing corrections.
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.
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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