Add to or Alter My Home

Additions that increase the footprint of the structure require a full site plan, including impervious surface calculations. Additions or alterations within the existing footprint of the structure require a site plan only if the addition/alteration increases the number of bedrooms in the structure and is served by an onsite wastewater system (septic). Increase in the number of bedrooms for structures served by on-site wastewater systems (septic) requires review to increase or verify the size and the functionality of the existing system.

To permit an addition or alteration you will need to submit:

  1. An application using the Wake County Permit Portal.
  2. A site plan meeting all the specifications listed below in Site Plan Requirements. (If the footprint of the structure will increase or the number of bedrooms will increase and is served by an onsite wastewater system (septic).
  3. Building Plans meeting all the specifications listed below in Building Plan Requirements. 
  4. A certificate of workers' compensation insurance or a completed affidavit of workers compensation exemption form for contractors.
  5. A notarized affidavit owner contractor form for projects costing $40,000 or more and where an owner is listed as the general contractor.


If the property is served by an onsite wastewater system (septic), the location of the new accessory building must be checked to ensure that it does not impact and maintains the required setbacks from the current wastewater system, its repair area and any on-site wells.

Further information regarding requirements may be obtained from: 

Health & Human Services-Onsite Water Protection
 919-856-7434  or
Groundwater/Well 919-856-7400

Building and Site Plan Specifications

Site Plan Requirements

A preliminary site plan is required before permits are issued. A final (as-built) site plan may be required prior to the issuance of a Certificate of Occupancy. A good resource for a site plan is a survey issued for a recent mortgage or refinance closing. Watch this video for more information.

A site plan includes the entire lot, drawn to scale, with the following:

  • Lot lines with dimensions and road frontage shown.
  • All existing and proposed buildings and structures with overall dimensions and, for proposed buildings and structures, the distance measured from the nearest fixed reference points (such as property lines, lot corners, existing building/structures, etc.) that can be used to precisely locate the proposed building/structures should be clearly shown.
  • Existing and proposed driveways, parking spaces, patios, pool decking, and walkways with width and surface material identified.
  • Where known, existing or proposed well, septic tank and drain field location(s) or sewer and water easements and proposed connection location(s).
  • When utilizing a Professional Option Permit (EOP, AOWE, SL 2022-11/A2) for wastewater (septic) permitting, site plans submitted for building permits must demonstrate the location of all wastewater system components including tanks and treatment systems, distribution devices, supply lines, primary and repair drain lines, etc. The wastewater system information must be provided by the appropriate design professional to be included on the site plan submission.
  • All water features including ditches, easements, buffers and flood hazard areas (FEMA or flood-prone soils).
  • The location, type and relevant dimensions and capacities of storm water management structures, associated easements and other devices.
  • All existing and proposed impervious surfaces clearly itemized and listed in square feet and as a percentage of the net lot size. This can be shown on the site plan or an attached impervious calculation worksheet.
  • Parcel identification number (PIN), address of property, north arrow, scale of the site plan, bar scale, and date map prepared (and any revision dates). 
  • If parcel is less than 5 acres, scales of 1" = 20', 30', 40', 50', 60' or 100' are acceptable on paper no larger than 11" x 17".
  • For a parcel of 5 acres or more, scales of 1” = 100’, 200’, 300’, 400’ or 500’ are acceptable in addition to the scales listed above and may be on any size paper. If the paper is larger than 11” x 17”, or the scale is smaller than 1”=100’, an inset or separate sheet must also be provided showing the proposed construction at a scale of 1” = 20’, 30’, 40’, 50’, 60’ or 100’.
  • As-built surveys must be labeled as such, be completed by a Professional Land Surveyor and include all the above. The date the as-built is prepared must be on or after the initial building final.

**These are minimum requirements. Special circumstances or small lots may necessitate further requirements**

Building Requirements


  • Name of designer, engineer, or architect with address and phone number.
  • If plans are stamped by a N.C. Architect or Engineer, their seals are required to be signed and dated.
  • Indicate heated square footage, garage square footage, unheated square footage, deck/porch sq. ft.
  • Number of bedrooms on the plans are required to match permit application and septic system.
  • All options being used need to be clearly marked. Please eliminate or mark out options not being used.
  • Drawings to scale (minimum 1/8").
  • Minimum plan size: Minimum 11x17; small structures 8.5" x 11" if legible.
  • Energy code requirements. Insulation, floors, walls and ceilings.

Elevations/Floor Plans

  • Front, sides and rear elevations.
  • Building height, mean roof height and story height.
  • Roof pitches.
  • Glazing U-Factor.
  • Floor Plans.
  • Rooms labeled as to their intended use. Please do not use bonus, flex or office.
  • Mark all unheated / unfinished areas.
  • Room, hallway and stair dimensions.
  • Window and door sizes and locations.
  • Label and show all fireplaces, prefab or masonry.

Foundation/Floor Framing

  • Wall footing width and depth, reinforcement if required.
  • Foundation wall type, size and reinforcement if required.
  • Pier footing size width and depth, reinforcement if required.
  • Pier sizes and solid cap.
  • Slab footings and layouts for mono-slabs.
  • Slab thickness and details, reinforcement if required.
  • Anchor bolt details.
  • Crawl space ventilation calculations or closed crawl space marked on plans.
  • Crawl space access size.
  • Girder size, number of members, species, grade and spans.
  • Floor joist direction, size, on-center spacing, species, grade and spans.
  • If using I-Joist, plans or layout will need to list manufacturer, series, size and on-center spacing.
  • If using open web floor trusses, layout from manufacturer required.
  • Openings in floors, headers and trimmers marked.
  • Floor sheathing type and thickness.

Wall & General Framing

  • Wall stud size, on-center spacing, species and grade.
  • Wall header size, number of members, species, grade and spans.
  • Number of jack and king studs for each opening.
  • Beam type or species/grade, size, number of members and span.
  • Stud column size, number of members, species and grade for beams and point loads.
  • Wall sheathing type and thickness.
  • Wall bracing method used.
  • Portal / narrow wall bracing detail, if required.
  • Point loads marked with load path and blocking requirements.
  • If brick veneer used, list lintel requirements.

Roof Framing

  • Roof rafter plan or layout from manufacturer if using engineered roof trusses.
  • Roof rafter direction, size, on-center spacing, species, grade and spans.
  • Roof tie down method and continuous load path.
  • Collar ties and rafter ties size and spacing.
  • Ridge board, hip and valley sizes.
  • Ceiling joist direction, size, on-center spacing, species, grade and spans.
  • Openings in ceilings or roof, headers and trimmers marked.
  • Roof sheathing type and thickness.
  • Roof vent calculations or marked as unvented.
  • Attic access size and location.

Decks & Porches

  • Dimensions- outside dimensions, spans between supports posts and footings.
  • Footing sizes- width, depth and locations.
  • Posts sizes.
  • Girder sizes, number of members and spans between supports.
  • Floor joist direction, size, on-center spacing and spans.
  • Bracing details for free standing decks and decks attached to structures with a floor height 4’ or taller.
  • Deck to house band attachment details.
  • Header size, number of members and spans between posts.
  • Ceiling joist direction, size, on-center spacing and spans.
  • Roof rafter direction, size, on-center spacing and spans.
  • Ridge size.