Copper Flashing Detail on a Kenilworth Colonial Revival
Copper is the standard flashing material on Kenilworth's Tudor and Colonial Revival estates — but the difference between good copper work and contractor shortcuts is in the specific detail execution, not the material spec itself.
Why this matters specifically in Kenilworth
Kenilworth's housing stock is one of the most architecturally consistent in Illinois — Tudor Revivals, Colonial Revivals, Craftsman estates, and Prairie-style homes built between roughly 1900 and 1940 with original specifications that almost universally called for copper flashing rather than aluminum or galvanized steel. When those original 80-to-100-year-old copper details reach end-of-life and need restoration or replacement, the work has to be done with the same level of detail the original installation received. Replacing soldered copper with mechanically-fastened aluminum on a Kenilworth Tudor is wrong specification work; the long-term consequences are immediate aesthetic mismatch, premature failure, and incompatibility with the cedar shake or slate roof above.
Chimney crickets — the detail that separates quality from shortcuts
A chimney cricket (also called a saddle) is the small triangular roof structure built behind any chimney wider than 30 inches measured perpendicular to the slope. Its job is to divert water around the chimney rather than letting water dam up against the back face. On Kenilworth Colonial Revivals with substantial brick chimneys, the cricket is one of the most visible copper details and one of the most failure-prone if executed badly. Quality cricket execution: the cricket is framed first as a structural element, then a copper cap is fabricated and soldered (not mechanically fastened) to the surrounding step and counter flashing, with a continuous solder line at every overlap. Shortcut execution: the cricket is sheet metal mechanically fastened with butyl tape sealant, no soldering, with the upper edge counter-flashed only with caulk against the chimney face. Quality crickets last 80+ years; shortcut crickets fail in 5-15 years and are responsible for a significant share of the leaks we encounter on aging Kenilworth properties.
Open-valley copper vs closed-valley
Two valley designs are common on Kenilworth estate homes. Open-valley designs expose the copper as a visible water channel running down the valley line — the copper is the visible roofing material in the valley itself, with the cedar shake or slate field stopping a few inches short on either side. Closed-valley designs hide the copper beneath interlaced shake or slate courses; the field material covers the copper, and only a sliver of copper edge is visible. Tudor Revivals and English country architecture often specify open-valley because the visible copper is part of the architectural design; Colonial Revivals more often use closed-valley for the cleaner profile. Either is correct; both should use 16-ounce copper minimum, hand-soldered overlap joints, and proper underlayment beneath. We've encountered open valleys on Kenilworth homes where the original 1920s copper is still serviceable today; the 'replacement' work some contractors propose is unnecessary.
Step flashing — the most common copper detail and the most often shortcut
Step flashing is the interlocking copper detail at any roof-wall intersection — between roof course and wall, with each piece bent to fit the specific roof pitch and lapped with the course above. On Kenilworth homes, step flashing is the detail where contractor shortcuts show up most often. Quality step flashing: each piece is hand-bent to the project's specific pitch, fabricated from 16-ounce copper, fastened to the deck (not the wall) so the wall masonry can move independently, and overlapped 4 inches minimum with the next course up. Counter flashing covers the top edge where copper meets masonry, with copper counter flashing inserted into a reglet cut into the brick or stone. Shortcut step flashing: pre-formed aluminum, mechanically fastened to both deck and wall (which fails when wall and roof move differently), with caulk-only counter flashing instead of inset counter flashing. The difference is invisible from the ground but determines whether the flashing lasts 5 years or 80.
Standing-seam copper accents on bay windows and dormers
Many Kenilworth Colonial Revivals have standing-seam copper accent roofs — small section roofs above bay windows, dormers, oriel projections, porches, and entry features. These aren't structural copper flashing; they're the primary roofing material for the architectural feature. Standing-seam construction has the panels running vertically up the slope with seams locked together at hand-soldered joints. We use 20-ounce copper (heavier than the 16-ounce flashing standard) because the visible standing-seam roof has higher visual stakes and longer expected exposure. The seam profile on Kenilworth restoration work should match the original — 1.5-inch standing seams on Colonial Revivals, sometimes 2-inch on larger Tudor projections. Custom fabrication is required for matching historic profiles; off-the-shelf standing-seam panels are rarely the right specification for restoration.
Soldering versus mechanical fastening — the line that determines quality
Quality copper roofing work uses soldered joints at every overlap, every seam, and every transition. Sweat-soldered joints with full-flow tin-lead or lead-free solder bond the copper into a continuous waterproof surface that lasts the full life of the copper itself. Mechanical fastening (sheet-metal screws, butyl tape, caulk) is used only where soldering is genuinely impractical, and even then sparingly. Many contractors who claim to do copper work actually do mechanical-fastened sheet copper — visually similar at installation but fundamentally different over a 50-year service life. We solder all primary copper joints in Kenilworth restoration work; if a contractor's proposal doesn't specify soldering as the bonding method, that proposal is for sheet-metal-fastened copper, not soldered copper, and the difference is significant.
Restoration of original 1920s and 1930s copper
Many Kenilworth homes have original copper that's now 80-100+ years old. Some of it is still serviceable. Some has reached end-of-life — typically failing at solder joints from extreme thermal cycling rather than at the copper sheet itself. Restoration involves selectively replacing failed sections (resoldering joints, replacing pieces that have suffered mechanical damage from tree fall or roof maintenance) while preserving the original copper inventory wherever possible. Pre-aged copper (with a forced patina that approximates 50-100 years of natural aging) is available for matching adjacent original copper. We've worked on Kenilworth homes where the original 1925 copper is still the primary flashing material today, with selective restoration extending its life another 50+ years. Replacement of intact original copper is rarely the right call.
What a quality copper proposal includes
A legitimate copper flashing proposal for a Kenilworth restoration spells out: copper weight specification (16-ounce field, 20-ounce visible standing-seam where applicable), bonding method (soldered with explicit solder type), specific scope by detail (every chimney with cricket, every valley, every wall transition itemized), source of copper (mill specification if requested), pre-aged matching for restoration zones if appropriate, soldering scope (continuous-flow joints at overlaps), counter-flashing reglet specifications for masonry transitions, and warranty terms on the workmanship. A one-page proposal that says 'copper flashing throughout' is a contractor who hasn't priced the actual scope. Copper at this level is detail-intensive and the proposal should reflect that.
The cost differential vs aluminum on Kenilworth restoration
On a typical Kenilworth Colonial Revival or Tudor restoration project, the copper flashing scope adds $15,000 to $40,000 to the project versus aluminum flashing at the same coverage. On a project total of $100,000 to $250,000+ for the cedar shake or slate roof above, this is a meaningful but not project-defining differential — and it's the right call on architecture where copper is the original specification. Substituting aluminum for copper on a Kenilworth restoration is wrong architecturally, fails at half the life of the surrounding cedar or slate roof, and creates a galvanic corrosion problem when copper components elsewhere on the roof come in contact with the aluminum. We default to copper recommendations on every Kenilworth project; we'll be transparent about the cost differential but won't recommend aluminum as a substitute.
Get a copper flashing assessment for your Kenilworth home
If your Kenilworth Colonial Revival, Tudor, Craftsman, or Prairie home has aging copper details — visible patina cracks, lifted sections, or any sign of water intrusion at flashing junctions — call us before assuming you need full replacement. We assess the existing copper inventory honestly, identify what's still serviceable versus what needs restoration, and write a proposal that preserves original architectural character wherever the underlying material allows. See our dedicated copper roofing and flashing service page for full system specifications. Leaders Roofing Corp, founded 1996 by Jan Koszyk, IL Roofing Unlimited License #104.010248. Call (847) 312-2727 or use the contact form.