The Complete Farmington Deck Permit and Building Guide

Building or rebuilding a deck in Farmington involves more than choosing boards and stairs. The project must fit the property, avoid easements, meet structural standards, and pass required inspections before the deck can be used. The deck permit requirements in Farmington, MN, also deserve early attention. 

Farmington’s 2024 deck handout says building permits are required for all decks. The city’s current online FAQ gives more specific permit triggers based on height, attachment, and use as a required exit. Because those two city resources are worded differently, homeowners should confirm the permit requirement with Farmington Building Inspections before ordering materials or removing an existing deck.

This guide explains the city’s published requirements and the planning decisions that can affect approval, construction, and final inspection.

When Does a Farmington Deck Require a Permit?

Farmington’s online building FAQ states that a permit is required when any of these conditions apply:

• The deck or platform is more than 30 inches above the adjacent grade.
• The deck or platform is attached to a structure supported by frost footings.
• The deck or platform serves the dwelling’s required exit door. (Farmington MN)

The city also requires permits for many deck repairs. Replacing required guards, decking, stair stringers, or stair treads requires approval, as does changing the deck’s original size or design. (Farmington MN) 

Do not assume a project is exempt because the framing will remain in place. A resurfacing job may still affect structural connections, guards, stairs, or code-required walking surfaces.

Apply Before Demolition or Construction Starts

Farmington currently directs residential and commercial applicants to submit building permit applications through its online BS&A permitting system. Deck and deck-resurfacing projects must include the city’s completed deck worksheet with the application. 

Starting first and applying later can create several problems. Parts of the deck may need to be removed so an inspector can view concealed footings, ledger connections, framing, or flashing. The city’s deck application also identifies a pre-inspection option for an unpermitted structure, with a listed fee.  

A permit can also become invalid when work does not begin within 180 days or when construction is suspended or abandoned for at least 180 days after it begins. 

What Must Be Submitted With the Permit Application?

Farmington requires enough information to determine where the deck will sit and how it will carry loads.

The city’s deck handout calls for a completed permit application, an accurate site survey, and scaled construction drawings. When the city does not have a survey available, the homeowner may need to provide a scaled property drawing showing the proposed deck.

The Site Plan

The site plan should show:

• The house
• Property boundaries
• Proposed deck location
• Deck dimensions
• Distance from lot lines
• Drainage and utility easements
• Other relevant structures

This drawing allows city staff to review setbacks, easement conflicts, and the amount of the property covered by structures.

The Deck Plan

The scaled plan view should identify:

• Existing house floor construction
• Deck length and width
• Ledger attachment method
• Footing type
• Post size and spacing
• Beam size
• Joist size and spacing
• Stair location
• Stringer size and spacing
• Decking material and dimensions

The Elevation Drawing

The elevation should show the deck from the side and include:

• Height above grade
• Footing design
• Post locations
• Guard height
• Guard material or product
• Stair position and dimensions

Incomplete plans may be returned. Farmington’s handout also states that changes made after plan approval can lead to an additional plan-review fee.

The plans do not need to look like architectural artwork. They do need to be scaled, readable, dimensioned, and consistent with the materials used during construction.

Farmington Deck Setback Requirements

Farmington’s deck handout states that decks in most residential areas must remain at least 6 feet from side and rear lot lines. However, the city tells applicants to check their individual survey or contact city staff because zoning conditions can vary.

A deck also cannot be placed within or across a drainage and utility easement. Total structural coverage on the property must remain within the percentage allowed by the applicable zoning district.

These rules make the site plan important. A deck may fit comfortably in the yard but still cross an easement or violate the setback when measured from the legal property line.

Fences, garden beds, mowing lines, and existing landscaping should not be treated as proof of the boundary. Use the property survey and visible survey markers where available.

Deck Footings Must Handle Minnesota Frost

Farmington requires frost footings for decks attached to structures that have frost footings. Conventional footings must extend at least 42 inches below grade, and the city specifies a minimum bottom diameter of 14 inches, although the actual footing size must be based on the load carried by each post.

The city assumes a soil-bearing value of 1,500 pounds per square foot when applying its footing table. Larger tributary loads require larger footings. A contractor should calculate how much deck area each post supports instead of using the same footing size throughout by habit.

Footings must be placed on dry, undisturbed soil. Posts must use approved pressure-preservative-treated lumber suitable for ground contact, and connectors must be compatible with treated wood.

Farmington may also accept alternative systems.

Pin Piers

Pin piers must be installed according to the manufacturer’s instructions. The caps must remain accessible during inspection so the pins can be measured, and the submitted plans must identify the pier type and size.

Helical Piers

Helical piers must be engineered and installed by licensed installers. Farmington requires preliminary design information during plan review and an installation report at final inspection showing the achieved torque and bearing capacity for each pier.

Ledger Attachment and Water Protection

The ledger is the board connecting an attached deck to the house. Failure at this connection can allow the deck to pull away from the structure.

Farmington requires the ledger to be attached using approved connections and fastener spacing based on the joist span and wall construction. The ledger must also be flashed to keep water from reaching the house band joist.

All penetrations through the home’s exterior finish must be flashed and sealed against water intrusion.

This detail matters in Farmington because rain, melting snow, and freeze-thaw cycles can expose a weak ledger area for years. Caulk alone should not replace properly layered flashing.

The city also warns that a deck cannot be supported by existing building cantilevers unless documentation proves those cantilevers can carry the added load.

Posts, Beams, Joists, and Approved Hardware

Deck framing cannot be sized using appearance or guesswork. Post height, beam span, joist span, species, grade, spacing, and tributary load all affect the required member size.

Farmington’s published table permits a 4-by-4 post only within limited height conditions. A 6-by-6 post may extend higher, subject to the table and the approved deck design. Posts bearing on concrete footings must have manufactured connectors that provide lateral restraint.

Joists connecting to the side of a beam or ledger must be supported with approved joist hangers. All required hanger holes must be filled with approved fasteners. Farmington specifically prohibits roofing nails and screws in joist hangers and does not allow modified hangers or improvised angle brackets.

The permitted joist spacing also depends on the decking:

• Nominal 5/4-inch wood decking may generally span joists at 16 inches on center when installed perpendicular or 12 inches when installed diagonally.
• Two-inch decking may generally span 24 inches perpendicular or 16 inches diagonally.
• Composite decking must follow its tested product requirements.

When composite boards are proposed, Farmington requires a code-compliant research report or comparable testing document for plan review.

Guardrail Requirements

Decks at least 30 inches above grade require guards.

Farmington’s handout requires deck guards to be at least 36 inches high. Openings must prevent a 4-inch sphere from passing through, and the guard system must resist a 200-pound lateral force.

A decorative railing is not automatically a compliant guard. The posts, connections, infill, and complete tested system must meet the structural requirement.

This is particularly important when installing composite, aluminum, cable, or custom guard products. Product documents should be included when needed, and the system should be installed exactly as approved.

Farmington Deck Stair Requirements

Deck stairs receive close review because small errors can create major fall risks.

Farmington publishes the following requirements:

• Stairs must be at least 36 inches wide.
• Treads must be at least 10 inches deep.
• Risers may be between 4 inches and 7¾ inches high.
• Variation between the tallest and shortest riser cannot exceed ⅜ inch.
• Stair stringers at grade must rest on a solid pad.

A stairway with four or more risers and a deck height below 30 inches requires a handrail on at least one side. Stairs serving a deck more than 30 inches above grade require guards on both sides and at least one handrail.

Handrails must be installed between 34 and 38 inches above the tread nosings. They must remain continuous for the full flight and return or terminate safely at a newel post or approved terminal.

Landings are required at the top and bottom of the stairway. Each landing must be at least as wide as the stairs and extend at least 36 inches in the direction of travel. Exterior stairs also need lighting at the top landing or another approved lighting arrangement that illuminates the stair sections.

Required Deck Inspections in Farmington

Inspections protect work that will later become difficult or impossible to view.

Farmington identifies these principal deck inspections:

Footing Inspection

Conventional footings must be inspected and approved before concrete is placed. Helical and diamond pier systems may be reviewed at framing or final inspection according to the city’s handout.

Do not pour early because rain is expected or concrete has already been delivered. Covering the excavation before approval can require removal and reconstruction.

Framing Inspection

Farmington states that a framing inspection is required for decks less than 60 inches above grade. This allows the inspector to review connections that may become difficult to see once decking is installed.

Final Inspection

The final inspection must be approved before the deck is used. Stairs, guards, and handrails must be complete at that point.

The city currently directs applicants to schedule inspections through its online scheduling system and asks them to provide first and second preferred time windows. 

Common Reasons Deck Projects Face Delays

Most approval problems begin with missing information or work that does not match the approved plan.

Common issues include:

• An incomplete site plan
• Incorrect property-line assumptions
• A deck crossing an easement
• Undersized footings
• Footings poured before inspection
• Unapproved changes to deck size
• Missing composite product reports
• Incorrect ledger fasteners
• Missing ledger flashing
• Roofing nails used in joist hangers
• Improvised beam-to-post connections
• Weak guard-post attachment
• Uneven riser heights
• Missing stair landings
• Calling for final inspection before guards or handrails are complete

Changes are sometimes necessary after excavation begins. However, the contractor should discuss those changes with the city before changing the approved structural layout.

Should Homeowners Pull Their Own Permit?

A homeowner may apply for the permit, but that also places permit coordination and code compliance responsibility on the homeowner.

When a contractor is managing the complete deck project, the contractor should usually be clearly identified on the application. Farmington does not publish an approved-contractor list, but city staff may be able to confirm whether a company has completed similar work locally. The city also directs residents to Minnesota’s contractor-license lookup and enforcement records. 

Before hiring a deck contractor, ask:

1. Who will submit the permit?
2. Who will prepare the scaled plans?
3. Is the permit fee included?
4. Who schedules each inspection?
5. Who meets the inspector?
6. Who corrects failed inspection items?
7. Are footing and framing calculations included?
8. Will the contractor provide product reports for composite decking and railing?
9. Will the final payment depend on final approval?

The contract should answer these questions before demolition begins.

Plan the Permit Before Finalizing the Deck Design

The permit process should shape the design, not follow it.

Setbacks may limit the deck width. Easements may affect the location. Footing loads may change post spacing. Composite boards may require closer joists. Stairs may need more yard space than expected once correct riser heights and landings are included.

Crest Exteriors can help Farmington homeowners plan a deck around the property, the intended materials, and the city’s review process. A complete scope should account for plans, structural framing, flashing, stairs, guards, inspections, and the final approval required before regular use.

Frequently Asked Questions