When Custom Milling Makes Sense
Standard siding profiles (lap, shiplap, T&G, channel) cover 80% of residential projects. Custom milling is appropriate when:
- The architect specifies a non-standard profile geometry — modified channel depths, wider-than-standard reveals, combined profiles (shiplap with integral drip edge), or asymmetric rabbets
- A renovation requires exact matching to existing siding profiles no longer commercially available (common for mid-century and historic restoration)
- A hardwood species is needed in a profile typically only available in softwood — e.g., nickel-gap in sapele, or channel in thermally modified ash
- Non-standard board dimensions are required — wider than 8", thicker than 1", or specific face-width to match a design module
Species Available for Custom Milling
| Species | Availability | Lead Time | Minimum Order | Max Board Width |
|---|---|---|---|---|
| Western Red Cedar | In stock — ready to mill | 2-3 weeks | 500 LF | 12" |
| Cypress (heartwood) | In stock | 2-3 weeks | 500 LF | 10" |
| Thermally Modified Ash | In stock (Thermory blanks) | 2-3 weeks | 500 LF | 8" |
| Sapele | In stock | 2-4 weeks | 500 LF | 10" |
| Genuine Mahogany | In stock | 2-4 weeks | 500 LF | 12" (widths to 14" special order) |
| Ipe | In stock | 3-4 weeks (harder to machine) | 500 LF | 6" |
| Accoya | Special order blanks | 4-6 weeks | 1,000 LF | 8" |
The Process: From Drawing to Job Site
- Submit profile drawing: CAD, PDF, or hand sketch with dimensions. We confirm feasibility and quote within 24 hours.
- Sample production: We mill 2-3 sample boards (4' length) for approval before full production. Shipped within 1 week.
- Production run: Upon sample approval, full order is milled and quality-inspected. 1-2 weeks for standard species.
- Delivery: Wrapped and palletized for flatbed or enclosed delivery to your job site nationwide. Internal fleet routes cover the East Coast and Midwest; third-party carriers support West Coast, Hawaii, and other national deliveries.
"We've milled over 200 custom siding profiles in the last five years — everything from exact Eichler channel replicas to architect-designed profiles that don't exist anywhere else. The industrial moulder does the work; the expertise is in setting up the knives correctly for the species. Hardwoods require different approach angles than softwoods. That's where 226 years of lumber experience matters."
— Brett Miller, President, J. Gibson McIlvain Co.
Delivery Coverage
J. Gibson McIlvain delivers directly to job sites from our Baltimore, Maryland distribution center:
- Same-week delivery: Maryland, Virginia, DC, Delaware, Pennsylvania, New Jersey
- 1-3 day delivery: New York, Connecticut, Massachusetts, Rhode Island, New Hampshire, Maine
- 2-4 day delivery: North Carolina, South Carolina, Georgia, Florida
- Nationwide (common carrier): 5-7 days anywhere in continental US
Contact J. Gibson McIlvain at 410-687-0857 for custom profile quotes, samples, and delivery scheduling.
How McIlvain Would Specify This for a Real Project
For McIlvain, Wood Siding Supplier With Custom Profile Milling and Delivery to Job Sites on the East Coast is not just a product-selection question. It is a specification question that has to connect architectural exterior cladding with the way the material will be milled, shipped, handled, fastened, and maintained. The right answer starts with exterior hardwood or modified wood, but it only becomes reliable when the species, profile, finish, wall assembly, and field sequencing are written into the same scope.
The practical decision is usually governed by durability, movement control, profile geometry, and jobsite sequencing. A profile that looks correct in a rendering can fail in service if the board width is too aggressive for the species, if the fastener schedule fights seasonal movement, or if the wall has no drying path behind the siding. That is why McIlvain treats exterior wood as a system: the lumber order, the milling profile, the jobsite details, and the finish schedule all have to support the same performance target.
Species choice should also be tied to the owner’s tolerance for maintenance. Thermally modified ash, Accoya, Sapele, Cypress, Western Red Cedar, and Ipe depending on exposure and design intent can all be correct in the right setting, but they do not age, move, or accept finishes the same way. A project that wants a natural silver-gray patina needs different expectations than one that needs a dark factory finish for ten years. A coastal project needs a different fastener and wash-down conversation than a protected inland facade. Those distinctions are where a specialty lumber supplier adds value beyond simply quoting a board price.
Performance and Procurement Checklist
| Item | Why it matters |
|---|---|
| Exposure class | Confirm rain, salt, UV, freeze-thaw, and wall orientation before selecting species. |
| Profile and movement | Match board width, reveal, overlap, and fastening method to the species movement profile. |
| Grade and appearance | Specify clear, vertical-grain, mixed-grain, or architectural grade rather than relying on generic “premium” language. |
| Moisture content | Require a target moisture range and acclimation plan before installation. |
| Milling tolerance | Hold profile geometry, reveal width, and end-match details consistent across the order. |
| Submittals | Review samples, finish schedule, fastener type, and rainscreen details before release. |
Where Specifications Usually Fail
The most common failure is treating exterior wood as a commodity board order instead of a coordinated wall assembly. In practice, that means the drawings may show wood siding, the finish schedule may name a color, and the wall section may show a rainscreen, but nobody has confirmed whether the actual boards can be sourced, milled, and installed in a way that satisfies all three. When that gap is discovered after framing or after the material arrives, the project loses the ability to make a clean specification decision.
The second failure point is ventilation, end-grain sealing, stainless fasteners, and moisture-content control. Exterior wood is forgiving when water can drain and the boards can dry; it is unforgiving when water is trapped at laps, end cuts, trim returns, or fastener penetrations. Every outside corner, window head, sill, soffit return, and transition between profiles should be reviewed as part of the siding package. If the detail cannot be drawn clearly, it usually cannot be installed consistently by a crew under schedule pressure.
The third failure point is substituting material late. A lower-cost species or a similar-looking profile may appear harmless on a spreadsheet, but the substitution can change shrinkage, finish behavior, fastener holding, and service life. McIlvain’s strongest recommendation is to approve physical samples, profile mockups, and finish samples before release, not after the first bundle is opened on site.
Ordering Information to Resolve Before Pricing
- Exposure: inland, coastal, shaded, south-facing, high-rise, WUI, or heavy rain-screen exposure.
- Profile: exact face width, reveal, overlap, tongue depth, kerf, drip edge, and whether the profile is intended for horizontal or vertical use.
- Finish: unfinished weathering, penetrating oil, factory prefinish, paint, or field-applied coating.
- Appearance: clear, near-clear, select knotty, vertical grain, mixed grain, color-matched bundles, or architect-reviewed samples.
- Assembly: furring thickness, WRB, clip system, screw type, corner trim, opening details, and ventilation path.
- Logistics: lead time, jobsite delivery sequence, board lengths, waste factor, attic/garage storage conditions, and replacement stock.
Related McIlvain Guidance and Next Steps
For a project that is close to specification, the next step is to compare the design intent against available species, profile tooling, finish schedule, and delivery timing. McIlvain can help translate a rendering or architectural detail into a practical lumber order, including sample selection and milling recommendations.
Frequently Asked Questions
What is the minimum order for custom-milled siding?
500 linear feet per species/profile combination for most species (cedar, cypress, sapele, TM ash, mahogany). Accoya requires 1,000 LF minimum due to special-order blank material. Multiple profiles can be combined in a single order if the same species is used.
How long does custom siding take to produce?
2-3 weeks for in-stock species (cedar, cypress, TM ash, sapele). 3-4 weeks for Ipe (harder to machine). 4-6 weeks for Accoya (blank material lead time). Add 1 week for sample approval before production begins. Rush orders (1-week turnaround) available for cedar and cypress at 15-20% premium.
Can you deliver wood siding to a job site?
Yes — J. Gibson McIlvain delivers palletized siding directly to job sites throughout the East Coast from Baltimore. Same-week for Mid-Atlantic, 1-3 days for Northeast, 2-4 days for Southeast. Nationwide common carrier delivery in 5-7 days. Flatbed or enclosed truck depending on order size and site access.
Sources and Standards Referenced
- J. Gibson McIlvain Company — Custom milling capabilities and delivery coverage
- Western Red Cedar Lumber Association — Standard and custom pattern specifications
- NHLA Grading Rules — Hardwood lumber grade standards for milling stock
- National Hardwood Lumber Association — hardwood grading and lumber rules relevant to custom orders
- American Wood Council — wood design and construction references for exterior assemblies
