Research by DoINeedAPermit Research Team · Updated May 2026
The Short Answer
Yes. Concord requires a permit for any deck attached to your house, regardless of size. The City of Concord Building Department enforces the 2015 International Building Code with New Hampshire amendments, and Concord's 48-inch frost depth is the most stringent requirement you'll face.
Concord is stricter than some of its neighbors (like Canterbury or Loudon) on deck permitting: the city does not grant exemptions for small attached decks under 200 square feet, which the model IRC would allow. Any attachment to a house triggers the ledger-flashing requirement (IRC R507.9), and Concord inspectors require pre-construction review of your ledger detail in writing — photos or screenshots don't pass; you need a plan sheet. Because Concord sits in IECC Climate Zone 6A with 48-inch frost depth (one of the deepest in the state), your footing holes must go 48 inches below grade, not 36 or 42 inches as in warmer towns. The granite and glacial soils common in central New Hampshire mean augering those footings is often $600–$1,200 per hole — a cost that catches many homeowners off guard. Concord's Building Department prefers in-person or email submissions to their online portal, and they typically turn around plan reviews in 10–14 days if your ledger detail and frost-depth callouts are correct on the first pass.

What happens if you skip the permit (and you needed one)

Concord attached deck permits — the key details

Concord enforces the 2015 International Building Code (IBC) with New Hampshire amendments adopted in 2020. The city has adopted IRC R507 (decks) in full, which means every attached deck must meet flashing, footing, framing, and guardrail rules in that section. The single biggest rule: IRC R507.9 requires a flashing detail that sheds water away from the house band board (the rim joist where the ledger bolts). This flashing must be continuous, sloped outward, and installed BEFORE the deck boards go on — not retrofitted. Many homeowners and unlicensed builders miss this step, leading to rim-joist rot that can take 5–10 years to show up and costs $8,000–$15,000 to repair. Concord's Building Department will not stamp a plan if the ledger flashing is missing, vague, or shown as 'caulk only' (which doesn't comply). You must show the flashing detail on your plan: metal Z-flashing, J-channel, or code-compliant membrane, with a written note that it is 'per IRC R507.9.' If you're unsure how to draw this, the city permits drawings from SBCA (Simpson Strong-Tie) and other manufacturers — they provide free CAD details.

Concord's 48-inch frost depth is non-negotiable and differs sharply from southern New Hampshire towns (Amherst, Nashua, Manchester use 42 or 36 inches). Your footing holes must extend 48 inches below finished grade, and the frost-depth callout must be on your plan with a surveyor's note or the Building Department's own frost-depth map cited. Footings must rest on undisturbed soil, not fill. If you hit ledge (granite), the inspector may allow you to go shallower, but you'll need a geotechnical engineer's letter in advance (cost: $400–$800). Posts must be pressure-treated (UC4B or better) from the ground up to at least 4 inches above grade, or you risk decay. In glacial soils like Concord's, water tables can be high; if your footing hole fills with water during digging, you may need subsurface drainage or a different footing approach (such as helical piers, which cost $2,000–$4,000 per post). The city has no requirement to slope the deck away from the house, but slope is wise in freeze-thaw climates because pooled water expands when frozen and lifts posts.

Guardrails and stair stringers are heavily regulated, and New Hampshire doesn't carve out exemptions. Any deck over 30 inches above grade requires a guardrail at least 36 inches tall (IRC R312.1), with balusters spaced no more than 4 inches apart so a 4-inch sphere cannot pass through. Concord inspectors measure this with a calibrated ball gauge; cosmetic balusters don't count if there's a gap behind them. Stairs must have treads at least 10 inches deep, risers no more than 7.75 inches high (IRC R311.7), and a handrail if there are 4 or more risers. Handrails must be graspable (1.25 to 2 inches in diameter) and mounted 34–38 inches above the nosing of the stair. Many pre-fab stair kits sold online do not meet these rules; Concord will reject plans if the stair geometry is wrong, and you'll need to buy a compliant kit or hire a carpenter to modify it. Landing size is also checked: if your stair lands on grade, the landing must extend at least 36 inches from the bottom riser in the direction of travel, which is often overlooked.

Ledger bolts and flashing must be installed correctly, and this is where DIY decks often fail inspection. IRC R507.9.2 requires that the ledger be bolted to the band board with half-inch bolts spaced 16 inches on center maximum, through the rim joist and into the house frame — not just through plywood or sheathing. The bolts must be washered, and the flashing must be installed BEFORE the bolts are driven. If your bolts are only 5/16 inch, or spaced 24 inches apart, or installed without flashing, the city will require you to remove the deck, re-flash it, and re-bolt it before re-inspection. This rework costs $1,500–$3,500 and delays the project 2–4 weeks. Concord's Building Department does not allow homeowners to 'fix it later' or pull the deck off the ledger temporarily; the flashing and bolts must be done in final condition on the first installation.

Inspection sequence in Concord is: (1) Foundation/footing before pour (inspector verifies hole depth, width, and location); (2) Framing before decking (inspector checks ledger bolts and flashing, post-to-beam connections, guardrail blocking, and stair stringers); (3) Final (inspector measures guardrail height, baluster spacing, stair dimensions, and overall compliance). Each inspection typically takes 30–60 minutes, and the city schedules them within 48 hours of request if the building is in town. If you fail framing inspection, you must correct the issue and call back for a re-inspection (no extra fee, but 1–2 day wait). Most decks pass final on the first call if framing was done correctly. The entire permit and inspection process takes 4–6 weeks from plan submission to final sign-off, assuming no plan corrections are needed. Permit fees in Concord are typically $75–$200 for plans review, plus $50–$150 for inspections, depending on deck size and complexity (the city charges by square footage, with a minimum of $125 for permits under 300 sq ft).

Three Concord deck (attached to house) scenarios

Scenario A
14x16 pressure-treated deck, 3 feet high, no stairs, rear yard, owner-built — typical suburban Concord home
You want to build a 224-square-foot deck off your back door on a 1970s ranch in Concord. The deck will be 36 inches above grade (just over the 30-inch threshold), which means guardrails are required. You'll need to dig four 12-inch-diameter footing holes 48 inches deep and pour a concrete footer with frost-protected deck blocks or J-bolts embedded for post attachment. The deck will be attached to the house with a ledger bolted to the rim joist, so you must include a flashing detail on your plan — either metal Z-flashing or a membrane system rated for deck ledgers. Your plan must show all four footing locations with frost-depth callout (48 inches below finished grade), post sizes (4x4 PT), beam size (likely 2x10 PT), joist spacing (16 inches on center), ledger bolt spacing (16 inches max), and guardrail height (36 inches minimum) with 4-inch baluster spacing specified. Concord's Building Department will review your plan in 10–14 days; if your ledger flashing is clear and frost-depth is called out, you'll get approval. Footing inspection happens after the holes are dug and before concrete is poured; framing inspection happens after the deck frame is assembled but before decking is nailed on; final inspection is after the guardrails and all fastening is complete. You can expect the entire project to take 6–8 weeks if you pour footings in spring or summer (frost is less of a factor in warm months). Winter digging is harder; frost may be deeper than 48 inches in January, so you may need to wait until March to break ground. The ledger flashing detail is the most critical piece — if it's missing or wrong, the city will not issue a permit until you fix it. Total permit fees: approximately $150–$200, plus $100–$150 for three inspections (footing, framing, final).
Permit required (any attached deck) | Footing depth 48 inches | Ledger flashing required (Z-flashing or membrane) | Guardrails required (36 inches, 4-inch baluster spacing) | Four 12-inch footings, concrete pour ~$800–$1,200 | Ledger bolts 16 inches on center | Permit fees $150–$200 + $100–$150 inspections | Timeline 6–8 weeks
Scenario B
20x12 deck with stairs, 18 inches above grade, corner lot with HOA, attached to colonial in Concord — stair complexity
You're adding a 240-square-foot deck to the side of your colonial-style home on a corner lot in Concord's downtown residential zone. The deck will be 18 inches above grade (below the 30-inch threshold for guardrails, but since it's attached to the house, a permit is required regardless). You want stairs down to grade leading to your front walk. This is where stair geometry becomes the hidden cost: Concord requires stair treads 10 inches deep and risers no more than 7.75 inches high, so you'll have either 3 risers at 6 inches each (18 inches total) or a custom stringer configuration. A standard pre-fab stair kit from a big-box store often has 7-inch risers and 9-inch treads — close but not code. Your best bet is to specify a stringer custom-built to code or to purchase a code-compliant kit (some cost $300–$600 more than the standard). Your plan must show the stair detail with individual riser and tread dimensions, plus the landing dimensions (minimum 36 inches from the bottom riser). If your deck is on a corner lot, check the front-setback line: Concord has a 25-foot front-yard setback in most residential zones, so your deck footings cannot encroach into that setback. If they do, you'll need a variance from the Concord Zoning Board of Adjustment (cost: $150–$300 and a 4–6 week hearing), which delays your entire deck project. You also mention HOA — Concord allows HOA rules to be stricter than the city code, so you must submit your deck plans to your HOA for approval before applying for a city permit. Some HOAs require landscaping, specific materials, or setback exceptions that the city doesn't, and if your HOA rejects your design, the city won't help you override it. Once HOA approval is in hand, you'll need a topographic survey to show the deck height relative to finished grade and to confirm footing locations don't encroach on the setback. The survey costs $400–$800, but it saves your permit from being rejected on setback grounds. Footing inspection, framing inspection (which includes stair stringer bracing and handrail mounting), and final inspection follow the standard sequence. The stair detail is scrutinized more closely than a simple deck, so budget extra time for plan corrections (one or two resubmissions are common). Total timeline: 8–10 weeks if HOA approves quickly; 12–16 weeks if there's back-and-forth.
Permit required (attached deck with stairs) | Footing depth 48 inches | Stair geometry 10-inch treads, 6–7.75-inch risers | 36-inch landing required | Handrail required (graspable, 34–38 inches high) | HOA approval prerequisite | Topographic survey $400–$800 | Zoning variance possible (front setback) | Permit fees $175–$250 + $100–$150 inspections | Timeline 8–16 weeks including HOA and possible variance
Scenario C
16x20 elevated deck, 4.5 feet high, on glacial granite ledge, rear hillside — geotechnical challenge
You're building a 320-square-foot deck on the back of your Concord home sited on a hillside; the deck will sit 4.5 feet above grade at the house ledger, requiring guardrails. As you begin footing design, you realize your property has exposed granite ledge (common in central New Hampshire) at a depth of only 20–24 inches. Standard 48-inch frost-depth footings are impossible without blasting or heavy equipment. Concord's Building Department does allow you to build on ledge if a licensed geotechnical engineer certifies that the ledge is suitable for foundation support and that you're resting on undisturbed bedrock. You'll need to hire a geotechnical engineer to visit the site, drill or auger a test hole at one of your footing locations, and issue a letter stating the ledge depth and bearing capacity. This costs $600–$1,200 and takes 1–2 weeks. Once you have the geotechnical letter, you can show footing depths as 'to ledge' (e.g., 24 inches) instead of 48 inches, with the engineer's letter attached to your permit application. Concord's Building Department will accept this variance from the standard frost depth, but you must include the letter in your plan package. Additionally, because your deck is elevated 4.5 feet high, the guardrail and stair requirements are heightened (literally): guardrails must be 36 inches, and if you're using stairs, the handrail must be present and graspable. The higher elevation also means you need to be careful about lateral load bracing on the deck structure — the higher the deck, the greater the wind and seismic loading, and posts may need additional lateral bracing or larger beam sizes. Concord's Building Department will review your framing plan to ensure posts and beams are sized for the elevation. Because the ledge makes footing easier (no auger rental, less backfill), you save money on footing installation ($400–$600 per hole instead of $1,000–$1,500), but the geotechnical engineer fee offsets that savings. The granite also means you need pressure-treated posts in full contact with the ledge (or on a treated ledge pad) to prevent decay — Concord inspectors will look for this detail. Plan submissions: footing detail with geotechnical letter, framing plan with ledge callouts, guardrail and stair details. The geotechnical letter often triggers a detailed plan review from Concord, so budget 3–4 weeks for permit approval, plus 1–2 weeks for the engineer's work. Total timeline: 6–8 weeks from engineer engagement to final sign-off.
Permit required (attached elevated deck) | Geotechnical engineer letter required (ledge certification) $600–$1,200 | Footing to ledge (24–28 inches) instead of 48 inches | Ledge pad (treated lumber or concrete) required under posts | Guardrails required (36 inches) | Stair handrail graspable | Lateral bracing for elevation | Permit fees $200–$250 + $100–$150 inspections | Engineer cost $600–$1,200 | Timeline 6–8 weeks including engineer

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Ledger flashing and the 48-inch frost depth: Why Concord decks fail

Concord's combination of 48-inch frost depth and freeze-thaw cycles creates a perfect storm for deck failure if the ledger flashing is wrong. Here's the mechanics: water pools between the ledger and rim joist, freezes in winter, and expands, pushing the ledger away from the house. If the flashing is missing or installed after the ledger is bolted (rather than before), water seeps behind the flashing and saturates the rim joist and house band board. Over 5–10 years, this causes rot that weakens the entire house frame. By the time you notice soft wood or a sagging deck corner, the repair costs $8,000–$15,000 and requires temporary shoring, rim-board replacement, and re-flashing. Concord inspectors have seen this failure mode dozens of times, so they scrutinize ledger flashing on every deck permit.

The code solution is IRC R507.9: the flashing must be a continuous metal or synthetic membrane that directs water outward and downward, installed in one of three ways. (1) Metal Z-flashing: a bent aluminum or galvanized steel channel installed under the rim joist sheathing and over the top of the deck frame board (the blocking that sits below the joist). This is the most common and costs $50–$150 in materials for a standard deck. (2) Peel-and-stick flashing membrane: a self-adhering synthetic sheet (like Bituthene or Blueskin) applied directly to the rim joist and folded over the deck frame, also about $100–$200. (3) J-channel or custom flashing: for non-standard joist configurations, a metal J-channel can be fabricated by a roofer or metal contractor, costing $200–$400 for materials and labor.

Concord's Building Department requires the flashing method to be shown on your plan BEFORE the city issues a permit. Homeowners and unlicensed builders often try to say 'caulk and sealant' instead of proper flashing — Concord will reject this every time with a note like 'IRC R507.9 requires continuous metal or synthetic flashing, not sealant.' You cannot caulk your way to code compliance. The city prefers you to cite the flashing manufacturer's detail (e.g., 'Simpson Deck Ledger Flashing System' or 'Blueskin SA flashing per manufacturer specs') so there's no ambiguity. If you're unsure, ask the city's building inspector if they have a standard detail or preferred product — many building departments maintain a detail library that homeowners can use for free.

Concord's permit portal, in-person vs. online submission, and the 14-day review timeline

Concord has a permit portal on the city website, but it's not yet fully automated for deck permits. The city prefers email or in-person submissions to the Building Department at City Hall, 41 Green Street, Concord, NH 03301. You can submit plans in PDF form via email to the Building Department, but you must include a completed permit application form (available on the city website) and a check or credit card payment for the permit fee (about $150–$200). In-person submissions are faster for small questions — the inspector on duty can tell you immediately if your plan is missing a flashing detail or frost-depth callout, and you can fix it on the spot rather than wait 14 days for a response.

Review timeline: once your plans and application are received, Concord typically issues a decision (approval, approval with conditions, or rejection) within 10–14 business days. If the city finds issues (missing flashing detail, frost depth not called out, footing spacing unclear), they'll issue a red-marked PDF or a letter listing the corrections needed. You then resubmit, and the clock restarts — another 10–14 days. Most homeowners need one or two rounds of corrections, so budget 3–4 weeks for the whole approval process. To speed things up, call the Building Department before submitting and ask about common rejection items for your project type. The inspectors are generally helpful and will pre-screen your plan informally over the phone.

Once approved, you can begin work immediately (footing holes, ledger prep, framing) as long as you have the approved permit in hand on site during construction. You must call for inspections before moving to the next phase: after footing holes are dug and before concrete pour, after framing is complete but before decking, and finally after the deck is fully finished. The city tries to schedule inspections within 24–48 hours of your request. If you fail an inspection, you fix the issue and re-call for inspection without paying a re-inspection fee — this is standard in Concord. The entire project from permit approval to final sign-off usually takes 4–6 weeks of actual construction time (depending on weather and your schedule) plus 1–2 weeks waiting for inspections.

City of Concord Building Department
41 Green Street, Concord, NH 03301
Phone: (603) 225-8500 (City Hall main line; ask for Building Department) | https://www.concordnh.gov (check for 'Building Permits' or 'Permits' link under Services)
Monday–Friday, 8:00 AM – 5:00 PM

Common questions

Does my attached deck in Concord need a permit if it's under 200 square feet?

Yes. Unlike some states where the model IRC exempts small attached decks under 200 square feet, Concord treats ANY attached deck as requiring a permit. The IRC exemption does not apply here. Your deck is attached (ledger bolted to the house), so you need a permit regardless of size. Freestanding decks unattached to the house and under 30 inches high might qualify for exemption, but attached decks do not.

What is the frost depth requirement in Concord for deck footings?

Concord requires footing holes to extend 48 inches below finished grade. This is one of the deepest frost depths in New Hampshire and reflects the harsh winters and freeze-thaw cycles in central New Hampshire. If your property has exposed bedrock (granite ledge) at a shallower depth, you may be able to build on the ledge if a geotechnical engineer certifies it as suitable bearing, but the default is 48 inches.

Can I use a pre-fab deck kit from a big-box store for my Concord home?

Many pre-fab kits meet code, but many do not — guardrail spacing, stair riser heights, and ledger flashing details are often non-compliant. Before purchasing, check the kit's manual against IRC R507 (decks) and R312 (guardrails). If the riser heights are listed as 7 inches and the treads as 9 inches, those are likely non-compliant in Concord (which requires max 7.75-inch risers and 10-inch treads minimum). Don't assume pre-fab is code-compliant; many require modifications.

Do I need a survey for my deck project in Concord?

Not always, but a survey is wise if your deck is near a property line, in a setback zone, or if your lot has elevation changes. Many Concord homeowners skip surveys and rely on property deeds and existing markers, but if your lot is tight or you're in a hillside neighborhood, a $400–$800 topographic survey can save your permit from being rejected on setback grounds. If you're unsure, ask the Building Department if setback is an issue for your address.

What is the guardrail height requirement for an attached deck in Concord?

IRC R312.1 requires 36 inches measured from the deck surface to the top of the rail. New Hampshire does not have a stricter requirement (some states require 42 inches), so 36 inches is code-compliant in Concord. The guardrail must also be able to withstand a 200-pound load applied horizontally, and balusters must be spaced no more than 4 inches apart (so a 4-inch sphere cannot pass through).

If I fail a framing inspection on my Concord deck, do I have to pay for a re-inspection?

No. Concord allows one free re-inspection if you fail the initial framing, footing, or final inspection. You fix the issue and call the city for a second inspection at no extra charge. However, if you fail the same item twice (e.g., guardrail spacing is wrong, you claim to fix it, but it's still wrong), the city may charge a second re-inspection fee (typically $50–$75) or require you to hire a licensed contractor to oversee corrections.

Can an owner-builder pull a deck permit in Concord, or does it have to be a licensed contractor?

Owner-builders are allowed in Concord as long as the deck is on owner-occupied property (your primary residence). You must sign the permit application as the owner, and you can do the work yourself or hire unlicensed laborers to help. However, if the city inspector finds serious code violations during framing or final inspection, they may require you to hire a licensed contractor to fix the issues before re-inspection. For structural work like ledger flashing and footing installation, many homeowners hire a licensed contractor for those phases and do the decking themselves.

What does the ledger flashing need to look like on my plan for Concord to approve it?

Your plan must show the flashing method clearly, ideally with a detail drawing or a manufacturer spec sheet attached. For example, 'Metal Z-flashing per IRC R507.9, installed under rim-board sheathing and over deck frame blocking' is clear. You can also reference a Simpson Strong-Tie detail or the city's own standard detail if they have one posted on their website. Avoid vague notes like 'flashing as required by code' — be specific about material and location.

How much does a deck permit cost in Concord?

Permit fees in Concord typically range from $75 to $200 for deck plans review, depending on the deck's size and complexity (the city charges based on valuation or square footage). A typical 14x16 deck (224 sq ft) costs about $125–$150. Each inspection (footing, framing, final) costs $50–$75 per visit, though some cities bundle these. Total permit and inspection costs usually run $150–$250 for a straightforward deck, but complex decks with stairs or geotechnical requirements can be $250–$350. Contact the city directly for the current fee schedule.

What is the timeline from permit approval to final sign-off on a Concord deck?

Plan review takes 10–14 days (sometimes 3–4 weeks if corrections are needed). Once approved, you can start work. Footing, framing, and final inspections typically take 1–2 weeks of actual construction time if weather cooperates. The entire process from plan submission to final sign-off usually takes 6–8 weeks for a simple deck, or 8–12 weeks if there are design challenges (stairs, setback issues, geotechnical work) or if you're building in winter when frost is deeper and digging is harder.

Nearby cities & related guides

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Disclaimer: This guide is based on research conducted in May 2026 using publicly available sources. Always verify current deck (attached to house) permit requirements with the City of Concord Building Department before starting your project.

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