Scenario / Conversion
Single-to-double garage door conversion cost in 2026
Converting two single garage doors (typically 9x7 singles separated by a load-bearing post) into one double (typically 16x7 or 18x7) is structural work, not a door swap. Total project cost in May 2026 runs $2,800 to $6,500, broken into engineering ($300 to $700), permit ($150 to $400), framing labour ($1,200 to $2,800), and door install ($1,150 to $2,600). The work takes 2 to 3 days and requires permit approval before demolition begins.
Cost breakdown by project component
| Project component | Cost low | Cost high | Notes |
|---|---|---|---|
| Structural engineer header design | $300 | $700 | Required for openings above 12 feet |
| Municipal building permit | $150 | $400 | Varies by jurisdiction |
| Demolition of two existing doors and center post | $300 | $700 | Temporary support during work |
| Engineered header beam installation | $700 | $1,800 | Glulam, LVL, or steel beam plus framing labour |
| Sheathing and trim repair | $200 | $500 | Exterior cosmetic restoration |
| New 16x7 door install (door plus labour) | $1,100 | $1,800 | Standard insulated steel install |
| Utility re-routing (if needed) | $500 | $2,000 | Electrical, HVAC, plumbing in center post |
2026 US national averages. Total project: $2,800 to $6,500 typical, $7,000+ if utility re-routing or 18-foot upsize. As of May 2026.
Section 02 / The structural decision
Why the center post matters and what an engineered header does
In a two-single configuration, the center post between the openings carries part of the roof load directly to the foundation. The two single-door headers above each opening are short-span (each spans roughly 9 feet) and can be standard doubled 2x10 or 2x12 lumber without engineering. The center post takes the rest of the load.
To create a single 16-foot opening, you remove the center post entirely. The new header must span 16 feet and carry the full roof load to the wall framing on either side of the opening. A 16-foot residential header is past the span limit for conventional framing lumber. The standard solution is a glulam (glued-laminated timber) beam, a series of LVL (laminated veneer lumber) plies, or a steel beam. Any of these requires engineering to size correctly for the specific load.
The engineering process: the structural engineer reviews the roof framing layout above the opening, calculates the load that the header must carry, and specifies a beam size and material that meets the load requirement with appropriate safety margin under the IRC or local building code. The engineered drawing is then submitted to the municipal building department as part of the permit application. The department's plan reviewer verifies the engineering and issues the permit if everything is in order.
This is not work that can be done without engineering. Trying to cut corners by using over-sized conventional lumber instead of an engineered beam can result in a permit denial, a failed inspection, or worse, an under-built header that fails years later under heavy snow load or seismic event. Use a structural engineer; the $300 to $700 fee is a small share of the total project cost.
Section 03 / Permit and inspection workflow
What the building department needs from you
The municipal building department typically requires three documents for the permit application: the engineer-stamped header specification, a site plan or floor plan showing the existing two-door configuration and the proposed single-door configuration, and a contractor identification (license number, insurance certificate). The permit fee ranges $150 to $400 depending on jurisdiction.
Once the permit is issued, the work proceeds in a specific sequence. The contractor begins by setting temporary structural support (typically a horizontal lumber ledger plus vertical posts) to carry the roof load while the existing header and center post are removed. The demolition exposes the existing framing. The new header is installed against the temporary support, then the temporary support is removed, transferring the load to the new header.
A framing inspection by the building department occurs after the header is installed but before the new sheathing goes up. The inspector verifies the header matches the engineered specification, the bearing connections are made correctly to the wall framing, and the fastener schedule is followed. Most inspections pass on the first visit if the work was done correctly. Failed inspections require re-work and a re-inspection visit.
The new door install happens after the framing passes inspection and the sheathing and exterior trim are complete. Standard residential garage door install workflow applies; the previous structural work does not affect the install workflow itself. Final inspection (combining framing, exterior, and door install) closes out the permit.
Section 04 / Is it worth it
Resale value, lifestyle benefit, and the alternative
The lifestyle benefit of single-to-double conversion is real for households that need to park two vehicles in the garage simultaneously and find the two-single configuration awkward (because the center post forces tight parking and complicates loading and unloading). The conversion gives you clear unobstructed parking for two vehicles with normal interior door access, which most modern households expect by default.
The resale value benefit varies by market. In suburban markets where the modern default is a double garage and the older two-single configuration feels dated, the conversion recovers 60 to 90 percent of the project cost in resale value. In markets where two singles is still common in the housing stock (older urban neighborhoods, older suburban tracts), the recovery may be lower.
The alternative to conversion is to keep the two-single configuration and replace each door individually. Two 9x7 single installs in the same visit run $700 to $1,200 total, much less than the $2,800 to $6,500 conversion. For households that do not specifically need the wider opening, two-single replacement is the much cheaper path.
For households that already park two cars in a two-single garage and find it works fine, do not undertake conversion just for resale optics. The capital cost is hard to recover unless the local market specifically prizes double-bay configuration.
For households considering the conversion seriously, get at least two contractor bids on the full project (engineering plus framing plus door install) before committing. Bid variance on structural work can be substantial because the framing labour is the largest single cost component and contractor pricing on framing labour varies more than door install pricing.