# Charleston Requires Four Copies of Your Site Plan at Engineer's Scale — Plus a Grand Tree Survey for Any Tree 24 Inches or Larger Near Your Project
Charleston's age and coastal position put its permit requirements in a different category from most nearby cities. The building and planning infrastructure is layered — four copies, engineer's scale, tree protection, coastal setbacks, stormwater applications, multiple affidavits — and understanding what each requirement means prevents the back-and-forth that can stall projects for months in this market.
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Engineer's Scale vs. Architectural Scale
Charleston's site plan must be drawn to engineer's scale. These differ from the architectural scales most design templates default to:
| Scale Type | Common Values | Used For |
|---|---|---|
| Engineer's scale | 1:10, 1:20, 1:30, 1:50, 1:100 | Site plans, civil drawings |
| Architectural scale | 1/4″=1′, 1/8″=1′, 3/16″=1′ | Floor plans, elevations |
A site plan submitted at 1/4″=1′ architectural scale will be returned for redrafting. State the engineer's scale clearly in the title block.
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The Grand Tree Survey Requirement
A Grand tree is any tree with a trunk diameter of 24 inches or greater measured at breast height (approximately 4.5 feet above ground). If any Grand tree exists within 40 feet of your project area, it must be:
- Located on the site plan — drawn as a point or circle showing canopy spread
- Labeled with the DBH measurement — e.g., "Oak, 26″ DBH"
- Documented in the Tree Affidavit — signed by the applicant or property owner
The 40-foot radius is measured from the outer edge of your proposed construction, not from your property line. A Grand tree in a neighbor's yard that falls within 40 feet of your proposed deck still needs to appear on your plan.
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Full Submission Package
Charleston site plan submittals are not just the drawing. The complete package:
| Document | Requirement |
|---|---|
| Site plan | 4 copies — engineer's scale, all required elements |
| Current approved and recorded plat | 4 copies |
| Letter of Intent | Signed by applicant or property owner |
| Restrictive Covenants Affidavit | Signed by applicant or property owner |
| Tree Affidavit | Signed by applicant or property owner |
| Water/wastewater availability letter | Current letter from utility provider |
| Stormwater Application | Required for all projects |
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What the Site Plan Must Show
| Element | Requirement |
|---|---|
| Property lines | All lot boundaries with accurate dimensions |
| Setbacks | Front/street side 25 ft, interior side 15 ft, rear 25 ft, accessory 5 ft |
| Existing structures | All existing buildings — location and footprint |
| Proposed project | Location, dimensions, use |
| Grand tree survey | All trees 24″ DBH or larger within 40 ft — located and labeled |
| Parking areas | Dimensioned, with paving material noted |
| DHEC-OCRM Critical Line | Coastal/tidal properties — with required signature |
| Wetlands | Saltwater wetlands delineated where applicable |
| Driveway width | Minimum 20 ft where driveway exists or is proposed |
| Building height | Measured from curb line to highest point of finished roof |
| North arrow | Required |
| Scale | Engineer's scale — stated on drawing |
| Title block | Address, owner, date |
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Charleston Setbacks
| Yard | Minimum |
|---|---|
| Front / Street side | 25 ft |
| Interior side | 15 ft |
| Rear | 25 ft |
| Accessory structures | 5 ft |
Setback reductions up to 15 ft may be approved by the Zoning and Planning Director when compatible with existing development patterns. Contact the Building Department to confirm your specific zoning district before drawing.
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When Site Plan Review Is Required
Standard residential permits go through normal building review. Site Plan Review (an additional, more involved approval process) is triggered when a project:
- Increases building footprint by more than 25%
- Involves earth disturbance of 5,000 sq ft or more
- Changes the property to a more intensive land use
- Involves re-occupying a building vacant for more than one year
If your project triggers Site Plan Review, expect a separate review step with additional processing time before the building permit can be issued.
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Coastal Properties: DHEC-OCRM
For properties near tidal waters, wetlands, or the coastal zone, the DHEC-OCRM Critical Line must be shown on the site plan with a required agency signature. Nothing may be constructed seaward of the Critical Line without OCRM approval. If your property is anywhere near tidal areas, contact DHEC-OCRM before finalizing your design.
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Project-by-Project Requirements
| Project | Key Charleston Consideration | Guide |
|---|---|---|
| Deck | Grand tree survey if 24″ DBH tree within 40 ft; 4 copies at engineer's scale | Permit required |
| Pool | Grand tree survey; DHEC-OCRM if coastal; stormwater application | Permit required |
| Shed (120 sq ft) | 4-copy site plan; Grand tree survey; 5 ft setback | Permit required |
| Fence | Verify permit requirement with Building Department | Verify |
| Garage | 4-copy plan; Grand tree survey; parking noted | Permit required |
| Addition | Triggers Site Plan Review if footprint increases >25% | Permit required |
| ADU | Full site plan; Grand tree survey; stormwater application | Permit required |
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Using the Site Plan Creator for a Charleston Permit
- Enter your address and select your parcel. Charleston County parcel data loads lot boundaries. See how to enter your address and select a parcel for parcel selection help.
- Generate setbacks. Add setback layers at 25 ft front, 15 ft interior side, 25 ft rear, 5 ft accessory. See generate setbacks.
- Place your project. Use add structure for additions and garages; specific project tools for decks, sheds, and pools.
- Mark Grand trees. Use place tree to locate any Grand trees (24″+ DBH) within 40 ft of the project. Label DBH on the plan.
- Build the title sheet. Use generate title sheet to add address, owner, and engineer's scale notation.
- Export four copies. Use export PDF and print four identical sets for submission.
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What This Doesn't Replace
The site plan creator generates preliminary, conceptual drawings. It does not produce a licensed land survey, a DHEC-OCRM coastal delineation, or a certified stormwater plan. For new single-family home construction, Charleston requires the site plan to be prepared, signed, and sealed by a South Carolina licensed land surveyor or design professional. The Tree Affidavit, Restrictive Covenants Affidavit, and Stormwater Application are separate documents requiring signatures and, in some cases, professional input. Final permit approval is at the sole discretion of the City of Charleston Building Department.
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Local Resources
- City of Charleston Building Inspection Services
- Charleston County GIS / Parcel Viewer
- DHEC-OCRM Coastal Permits
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Nearby South Carolina Cities
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Frequently Asked Questions
1. What is engineer's scale and why does Charleston require it?
Engineer's scale uses decimal divisions — 1:20, 1:50, 1:100 — standard for site and civil drawings. Architectural scale uses fractional inch-to-foot ratios (1/4″=1′, 1/8″=1′). Charleston specifies engineer's scale for site plans. Submitting at architectural scale results in a return for re-drafting.
2. What is DBH and how do I measure it for the Grand tree survey?
DBH is Diameter at Breast Height — the trunk diameter measured at 4.5 feet above ground. To measure: wrap a flexible tape around the trunk at that height to get circumference, then divide by π (3.14) to get diameter. 24 inches or more = Grand tree.
3. My neighbor has a large oak — does it appear on my plan?
Yes, if it's within 40 feet of your project area. The 40-foot zone extends from the outer edge of your proposed construction, not from your property line. Trees on adjacent properties within that radius must be located and labeled.
4. What is the DHEC-OCRM Critical Line?
A coastal boundary established by SC DHEC's Office of Ocean and Coastal Resource Management marking the limit of regulated coastal zone. No construction seaward of this line without OCRM approval. For properties near tidal waters, the line must appear on the site plan with an OCRM signature.
5. What triggers Site Plan Review?
Footprint increase more than 25%, earth disturbance of 5,000+ sq ft, change to more intensive use, or re-occupying a building vacant more than one year.
6. Do I need a stormwater application for a residential permit in Charleston?
Yes — it's a listed required document in the submission package. Contact the Building Department to confirm the level of detail required for your specific project scope.
7. What is the Tree Affidavit?
A signed statement from the applicant or property owner attesting to the accuracy of the Grand tree survey information on the site plan. It is part of the four-document affidavit package submitted with every permit application.
8. Can I pull my own permit in Charleston as a homeowner?
Homeowners can pull permits for their own property. For new single-family home construction specifically, the site plan must be signed and sealed by a licensed SC surveyor or design professional. For smaller residential improvements (decks, sheds, pools), verify the sealed plan requirement with the Building Department for your project type.
9. What is the minimum driveway width?
20 feet minimum — show this on the site plan where a driveway exists or is proposed.
10. How is building height measured in Charleston?
From the curb line to the highest point of the finished roof. Show this measurement on the plan or in the title block notes.
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Start Your Charleston Site Plan
Four copies. Engineer's scale. Grand trees labeled. Setbacks at 25/15/25/5 ft. Enter your Charleston address, pull county parcel data, place your project, locate Grand trees within 40 ft, generate the title sheet, and export four copies. First plan is free.
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