# Architectural-shingle overlay option — September 16, 2026

Alternative to the preserved insulated steel roof option. Six cabins; latest geometry and Forest & Oxblood default finishes retained. New architectural shingles over retained asphalt shingles. No new insulation, purlins, structural purlin anchors, steel panels or metal ridge cap. Edge flashing remains metal. This option adds no meaningful insulation benefit.

## Quantities and complete working estimate

Net roof 5,760 SF / 57.6 squares. Purchase approximately 6,400 SF / 64 squares / 192 bundles (32 bundles per cabin), about 11.1% waste. Stated bundle coverage of 33.33 SF gives 6,399.36 SF, rounded to 6,400.

| Item | Six-cabin quantity / basis | Cost |
|---|---|---:|
| GAF Timberline HDZ field shingles | 192 bundles; $7,500–$8,000 budget, midpoint used | $7,750.00 |
| Pro-Start starter | 768 net LF eaves/rakes; 8 × 120 LF bundles at $54.97 | $439.76 |
| Seal-A-Ridge caps | 144 net LF; 7 × 25 LF bundles at $62.97 | $440.79 |
| Drip/rake edge flashing | 768 net LF; 86 × 10 LF pieces at $20 allowance | $1,720.00 |
| Galvanized roofing nails | provisional 30,000 total including field and accessories | $600.00 |
| Compatible roof cement / hand sealing | $75/cabin provisional | $450.00 |
| Edge backing / minor repair wood | $320/cabin retained allowance | $1,920.00 |
| **Materials** | | **$13,320.55** |
| Paid helper | 40 days × 8 hours × $25; retained planning allowance | $8,000.00 |
| Equipment / access | steep roof access, shared | $1,800.00 |
| Delivery / handling | separate unquoted allowance | $1,200.00 |
| **Direct subtotal** | | **$24,320.55** |
| Contingency | 15% of direct subtotal | $3,648.08 |
| **Six-cabin total** | | **$27,968.63** |
| **Per cabin** | | **$4,661.44** |

Field-price-only budget sensitivity: $27,681.13–$28,256.13 for the program. Steel comparison at $4/LF remains $46,253.28; shingle option is $18,284.64 lower using unrounded totals. No assumed labor saving: the helper allowance is provisional, not a shingle production schedule. Owner labor is unpaid and excluded. No tax or permit/review allowance. Full repainting, door/light replacement, deck improvements and major structural/deck repairs are not priced.

## Pricing evidence

[Home Depot field-shingle listing](https://www.homedepot.com/b/Building-Materials-Roofing-Roof-Shingles/FITMENT/Pick-Up-Today/N-5yc1vZc5rbZ1z175a5Z1z18gk5): Timberline HDZ published $38.67 per bundle at 39+ bundles, verified September 16, 2026. 192 × $38.67 = $7,424.64. Budget deliberately uses $7,750. Published benchmark is not a confirmed local delivered quote.

[Home Depot GAF accessory listings](https://www.homedepot.com/b/Building-Materials-Roofing-Roof-Shingles/GAF/N-5yc1vZc5rbZll?emt=plp_pecb_2503): Pro-Start 120 LF $54.97; Seal-A-Ridge 25 LF $62.97 (displayed color Hickory). Verify selected color, local price and availability. Remaining accessory rates are explicit allowances, not researched quotes. Delivery is separate; no supplier has been contacted.

## Assembly and installation assumptions

[GAF HDZ installation instructions](https://www.gaf.com/en-us/document-library/documents/productdocuments/residentialroofingdocuments/shinglesdocuments/timberlineroofingshinglesdocuments/architecturalshinglesdocuments/timberlinehdzdocuments/Installation_Instructions__Timberline_HDZ_High_Definition_Lifetime_Shingles_.pdf) include reroofing over prepared existing asphalt. Repair loose/curled/lifted areas, clean the surface, and confirm sound deck and suitability for added weight. Fasteners must penetrate wood decking at least ¾ inch (or through thinner plywood); choose length from actual retained/new roof thickness and exposed ceiling clearance. No universal nail length is specified here.

The model illustrates six nails per field unit in a covered nailing zone, with illustrative accessory nails; verify the selected product pattern. Nominal 60° is about 20.8:12, close to GAF’s 21:12 mansard threshold: confirm actual pitch and hand-sealing/nail-zone requirements. Roofing cement allowance is retained for steep/cold-weather sealing. No new full underlayment layer is included in this requested overlay; final edge/weather detailing may change accessory scope.

## Model

Both viewers share corrected cabin geometry, recessed openings, 50-inch rear window bank, 148-inch centered deck and footing span, floor edges and end-frame finish. Shingle mode removes the new foam/purlins/steel, displays staggered nominal 39⅜-inch shingle units in 5⅝-inch courses, starter, edge flashing and individual cap sections. Fasteners follow material placement and fade from highlighted to metal finish. Quantities in the estimate govern purchasing; animation subdivisions and cut pieces are illustrative. Roof colors approximate the selected palette, not confirmed GAF color matches. Existing concept render images still show steel.