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Converted dwellings or rooming house
421 GRAND AVENUE
BROOKLYN · BIN 3056806
💬 Discuss this project
1872Year Built
4Stories
C5Building Class
R6BZoning
3,540 sfGross Floor Area
6Units
Rent Stabilized83 Open Violations 81 unresolved · 2 paperwork only ▸FDNY Report ↗
Converted dwellings or rooming house · 2,385 sf lot · 1.48 FAR built · Flood zone X
Locations of Work
ArchitectureStructuralFire Protection
Permit Issued — active, not yet Signed-off
Floor 4Under Construction19p · 2 filings · 20 docs
Floor 3Under Construction19p · 2 filings · 20 docs
Floor 2Under Construction19p · 2 filings · 20 docs
Floor 1Under Construction18p · 2 filings · 20 docs
CellarUnder Construction20p · 2 filings · 20 docs
BasementUnder Construction17p · 1 filing · 20 docs
Sub-BasementUnder Construction2p · 1 filing · 9 docs
▾Owner History (Filing Record)
Companies and organizations named on filings. Individual owners are not shown.
OwnerFilingsMost Recent
BILLY ENTERPRISES203/21/2026
SKYWORX CONTRACTING203/21/2026
▾Sales History (ACRIS)
DatePriceUnitSeller → Buyer$/sf
12/29/2025$3.2M—— → —$904/sf building
▾Design Consultants (Architect / Engineer of Record)
FirmFilingsMost Recent
YANG ENGINEERING LLC507/23/2026
JIAN ENGINEERING PLLC206/02/2026
▾Filing Representatives (Expediters)
RepresentativeFilingsMost Recent
SD DESIGN STUDIO403/21/2026
▾Contractors (License-Anchored)
FirmTradeRolesMost Recent
ACER CONSTRUCTION INCGeneral Contractor408/14/2026
WINWAY DEVELOPMENT LLCGeneral Contractor104/09/2026
▾Special Inspection Agencies
AgencyLicense #FilingsMost Recent
YANG ENGINEERING LLC8376507/22/2026
Building Lifecycle
All (126)Filed (7)Permit Issued (5)Violation (60)Inspection (9)Objection (33)Special Inspection (12)
08/13/2026
Permit issued — Structural
B01320919-S2-ST
08/10/2026
Permit issued — Foundation
B01320919-S3-FO
07/23/2026
Filed — Alteration CO
APPLICATION IS FILED FOR A CONVERSION FROM 17 FURNISHED ROOMS AND 4 KITCHENETTES TO 5 FAMILY. OBTAIN NEW CERTIFICATE OF OCCUPANCY.
B01320919-S5
07/22/2026
Filed — Alteration CO
APPLICATION IS FILED FOR A CONVERSION FROM 17 FURNISHED ROOMS AND 4 KITCHENETTES TO 5 FAMILY. OBTAIN NEW CERTIFICATE OF OCCUPANCY.
B01320919-S4
07/22/2026
Objection resolved — Addressed
07/22/2026
Objection resolved — Addressed
07/22/2026
Objection resolved — Addressed
07/22/2026
Objection resolved — Addressed
07/22/2026
Objection resolved — Addressed
07/22/2026
Objection resolved — Addressed
07/22/2026
Objection resolved — Addressed
07/22/2026
Special inspection requirement — Subsurface Investigations (Borings/Test Pits)
Rajasekhar Sakhamuri
07/22/2026
Special inspection requirement — Structural Wood Frame
Jian Yang
06/22/2026
Permit issued — Construction Fence
B01417913-I1-FN
06/22/2026
Objection raised — Structural
06/22/2026
Objection raised — Scope
06/19/2026
Filed — Alteration
SUBMIT TEMPORARY CONSTRUCTION FENCE WORK AT OPEN SPACE. NO CHANGE IN USE, EGRESS OR OCCUPANCY.
B01417913-I1
06/18/2026
Permit issued — General Construction
B01320919-I1-GC
06/17/2026
Objection raised — Cost
06/17/2026
Objection raised — Scope
06/15/2026
Objection raised — Admin
06/15/2026
Objection raised — Structural
06/15/2026
Objection raised — Other
06/02/2026
Filed — Alteration CO
APPLICATION IS FILED FOR A CONVERSION FROM 17 FURNISHED ROOMS AND 4 KITCHENETTES TO 5 FAMILY. OBTAIN NEW CERTIFICATE OF OCCUPANCY.
B01320919-S2
06/01/2026
Filed — Alteration CO
APPLICATION IS FILED FOR A CONVERSION FROM 17 FURNISHED ROOMS AND 4 KITCHENETTES TO 5 FAMILY. OBTAIN NEW CERTIFICATE OF OCCUPANCY.
B01320919-S3
05/27/2026
Special inspection requirement — Final
Jian Yang
05/27/2026
Special inspection requirement — Structural Stability – Alterations of existing buildings
Jian Yang
05/27/2026
Special inspection requirement — Footing and Foundation
Jian Yang
05/27/2026
Special inspection requirement — Structural Stability – Alterations of existing buildings
Jian Yang
05/27/2026
Special inspection requirement — Subgrade Inspections
Jian Yang
05/27/2026
Special inspection requirement — Final
Jian Yang
05/27/2026
Special inspection requirement — Concrete - Cast-In-Place
Jian Yang
05/27/2026
Special inspection requirement — Excavations - Sheeting, Shoring, and Bracing
Jian Yang
05/04/2026
Violation issued (HPD, open)
A
03/27/2026
Permit issued — General Construction
B01338003-I1-GC
03/18/2026
Inspection — Pass-Final PL - Up to 3 Requested Floors
Pass
View inspection ↗
03/16/2026
Objection resolved — Addressed
02/12/2026
Objection resolved — Addressed
02/09/2026
Objection resolved — Addressed
02/06/2026
Objection raised — Cost
02/06/2026
Objection raised — Scope
01/29/2026
Objection resolved — Addressed
01/20/2026
Objection resolved — Addressed
01/07/2026
Objection raised — Fire_Protection
01/07/2026
Objection raised — Cost
01/07/2026
Objection raised — Scope
12/23/2025
Filed — Alteration
PROPOSE INTERIOR RENOVATION WORK AT CEL., BAS., 1ST THRU 4TH FLOOR AS PER PLANS. NO CHANGE IN USE, EGRESS OR OCCUPANCY.
B01338003-I1
12/23/2025
Objection resolved — Addressed
12/19/2025
Special inspection requirement — Fire-Resistance Rated Construction
Jian Yang
12/19/2025
Special inspection requirement — Fire-Resistant Penetrations and Joints
Jian Yang
12/11/2025
Objection resolved — Addressed
12/11/2025
Objection resolved — Addressed
12/11/2025
Objection resolved — Addressed
12/08/2025
Objection raised — Zoning
12/08/2025
Objection raised — Fire_Protection
12/08/2025
Objection raised — Fire_Protection
12/08/2025
Objection raised — Fire_Protection
12/08/2025
Objection raised — Fire_Protection
11/26/2025
Filed — Alteration CO
APPLICATION IS FILED FOR A CONVERSION FROM 17 FURNISHED ROOMS AND 4 KITCHENETTES TO 5 FAMILY. OBTAIN NEW CERTIFICATE OF OCCUPANCY.
B01320919-I1
11/20/2025
Violation issued (HPD, open)
I
Latest 60 of 126 events.
Permit / Filing Register
SourceWork TypeStatusApplicantIssued
DOB NOWStructuralPermit IssuedACER CONSTRUCTION INC08/13/2026
DOB NOWFoundationPermit IssuedACER CONSTRUCTION INC08/10/2026
DOB NOWConstruction FencePermit IssuedACER CONSTRUCTION INC06/22/2026
DOB NOWGeneral ConstructionPermit IssuedACER CONSTRUCTION INC06/18/2026
DOB NOWGeneral ConstructionPermit IssuedWINWAY DEVELOPMENT LLC03/27/2026
BISEQISSUEDSKYWORX CONTRACTING INC09/12/2014
1 job · most recent 07/23/2026
Sprinkler System
FiledStatusContractorScope
07/23/2026——Sprinkler System
1 job · most recent 07/23/2026
Gas Water/Sanitary
FiledStatusContractorScope
07/23/2026——Gas, Water/Sanitary
1 job · most recent 08/12/2026
General Wiring
FiledStatusContractorScope
08/12/2026Permit IssuedERIC & NG ELEC'L, INC.General Wiring
1 job · most recent 07/23/2026
Wood
FiledStatusContractorScope
07/23/2026Permit IssuedACER CONSTRUCTION INCWood
1 job · most recent 06/19/2026
Fence
FiledStatusContractorScope
06/19/2026Permit IssuedACER CONSTRUCTION INCFence
▾Field Inspections (DOB CAP) — 9
DateTypeResultReport
03/18/2026Pass-Final PL - Up to 3 Requested FloorsPassView ↗
11/07/2025Certified Water and Sanitary-WS-Sanitary Piping-RoughingCertifiedView ↗
10/17/2025Certified Gas-Gas-Piping-RoughingCertifiedView ↗
10/07/2025Certified Water and Sanitary-WS-Sanitary Piping-UndergroundCertifiedView ↗
09/26/2025Certified Storm Drainage-ST-Piping-RoughingCertifiedView ↗
09/26/2025Certified Water and Sanitary-WS-Sanitary Piping-RoughingCertifiedView ↗
09/26/2025Certified Water and Sanitary-WS-Sanitary Piping-UndergroundCertifiedView ↗
08/14/2025Certified Storm Drainage-ST-Piping-RoughingCertifiedView ↗
08/14/2025Certified Storm Drainage-ST-Piping-UndergroundCertifiedView ↗
▾Special Inspection Requirements (DOB NOW) — 12
DateRequirementInspectorRole
07/22/2026Subsurface Investigations (Borings/Test Pits)Rajasekhar Sakhamurispecial
07/22/2026Structural Wood FrameJian Yangprogress
05/27/2026FinalJian Yangprogress
05/27/2026Structural Stability – Alterations of existing buildingsJian Yangspecial
05/27/2026Footing and FoundationJian Yangprogress
05/27/2026Structural Stability – Alterations of existing buildingsJian Yangspecial
05/27/2026Subgrade InspectionsJian Yangspecial
05/27/2026FinalJian Yangprogress
05/27/2026Concrete - Cast-In-PlaceJian Yangspecial
05/27/2026Excavations - Sheeting, Shoring, and BracingJian Yangspecial
12/19/2025Fire-Resistance Rated ConstructionJian Yangprogress
12/19/2025Fire-Resistant Penetrations and JointsJian Yangspecial
▾Documents — 71 on file (BIS + DOB NOW)
▸Plans & Drawings9
▸DOB NOWPlans/Sketch9
08/19/2026B01320919-P1Request digital key ↗
08/19/2026B01320919-S6Request digital key ↗
08/19/2026B01320919-S5Request digital key ↗
Showing 3 of 9 on file for this type
▸Applications & Permits9
▸DOB NOWLPC Approval/Permit7
08/19/2026B01320919-P1Open ↗
08/19/2026B01320919-S6Open ↗
08/19/2026B01320919-S5Open ↗
Showing 3 of 7 on file for this type
▸BISPLAN / WORK APPROVAL APPLICATION1
09/10/2014340184357Open ↗
▸BISWORK PERMIT APPLICATION1
09/10/2014340184357Open ↗
▸Zoning, Tax Lot & Property Records2
▸DOB NOWHouse Number Verification: TOPO Stamp2
08/19/2026B01320919-I1Open ↗
08/13/2026B01320919-I1Open ↗
▸Seals & Professional Certifications20
▸DOB NOWDPL-1: Design Professional Seal & Signature8
08/19/2026B01320919-P1Open ↗
08/19/2026B01320919-S5Open ↗
08/19/2026B01320919-S4Open ↗
Showing 3 of 8 on file for this type
▸DOB NOWSpecial Inspector Seal & Signature5
08/26/2026B01320919-S2Open ↗
08/23/2026B01320919-S3Open ↗
08/23/2026B01320919-S3Open ↗
Showing 3 of 5 on file for this type
▸DOB NOWProgress Inspector Seal & Signature4
08/26/2026B01320919-S2Open ↗
08/23/2026B01320919-S3Open ↗
08/22/2026B01320919-P1Open ↗
Showing 3 of 4 on file for this type
▸BISREQUIRED ITEMS CHECKLIST FOR PROFESSIONAL CERTIFICATION1
09/10/2014340184357Open ↗
▸BISPROFESSIONAL CERTIFICATION STATEMENT1
09/10/2014340184357Open ↗
▸BISTECHNICAL REPORT STATEMENT OF RESPONSIBILITY1
09/10/2014340184357Open ↗
▸Safety & Tenant Protection12
▸DOB NOWHPD-3: Single Room Occupancy Multiple Dwelling (SRO MD) Anti-Harassment Checklist9
08/19/2026B01320919-S6Open ↗
08/19/2026B01320919-P1Open ↗
08/19/2026B01320919-S5Open ↗
Showing 3 of 9 on file for this type
▸DOB NOWStreet Tree Checklist2
08/19/2026B01320919-P1Open ↗
08/13/2026B01320919-I1Open ↗
▸BISSRO MD ANTI-HARASSMENT CHECKLIST1
09/10/2014340184357Open ↗
▸Environmental & Asbestos9
▸DOB NOWDEP ACP-5: Asbestos Assessment Report8
08/19/2026B01320919-P1Open ↗
08/19/2026B01320919-S5Open ↗
08/19/2026B01320919-S4Open ↗
Showing 3 of 8 on file for this type
▸BISASBESTOS: CERTIFICATION (DEP ACP5)1
09/10/2014340184357Open ↗
▸Inspections & Test Reports3
▸BISTECHNICAL REPORT: RESPONSIBILITY1
09/10/2014340184357Open ↗
▸DOB NOWTR4 Test Report and Plot Diagram1
08/14/2026B01320919-S3Open ↗
▸DOB NOWSOIL REPORT1
08/14/2026B01320919-S3Open ↗
▸Approvals, Objections & Sign-offs1
▸BISLANDMARKS APPROVAL1
09/10/2014340184357Open ↗
▸Filing & Intake Forms1
▸BISEFILING JOB APPLICATION COVER SHEET1
09/10/2014340184357Open ↗
▸Other Documents5
▸DOB NOWProof of Historic Building3
08/19/2026B01320919-P1Open ↗
08/13/2026B01338003-I1Open ↗
08/13/2026B01320919-I1Open ↗
▸DOB NOWProperty Ownership Certification2
08/19/2026B01320919-P1Open ↗
08/19/2026B01320919-I1Open ↗