Harmonia Builders
The frame under a fire-resistant deck matters as much as the surface. We standardize on non-combustible steel, aluminum or concrete substructure, all Class A, so the whole assembly resists fire. Wood is shown only as a benchmark.
| System / Brand | Material | Combustible | Fire rating | Est. installed $/sf, SF Bay** | Lifespan | Corrosion / coastal | Key notes | Add to calc |
|---|---|---|---|---|---|---|---|---|
| TimberTech Aluminum Framing | Aluminum | No | Non-comb, Class A | $35-50 | 40-50+ yr | Excellent, won't rust | Lightest; won't rust; dead-flat; pairs natively with TimberTech decking; best for coastal and under porcelain or aluminum; premium cost | Add → |
| Fortress Evolution | Galvanized steel | No | Non-comb, Class A | $25-35 | 25-50 yr | Good, galvanized + coated | Very strong, long spans, dead-level and straight; 25-yr warranty; WUI compliant | Add → |
| Custom concrete (slab / podium) | Poured concrete | No | Non-comb, Class A | $12-60+ | 50+ yr | Excellent, can crack | Ultimate non-combustible base. On-grade slab ~$12-18/sf (Bay Area); elevated structural slab ~$30-60+/sf (needs engineering). Ideal for patios, podium/roof decks and pedestal-set porcelain; heavy; slope for drainage | Add → |
| Pressure-treated wood | Softwood lumber | Yes (fuel) | Combustible | $10-16 | 10-40 yr | Poor, rots / warps | Cheapest upfront but combustible; benchmark only, Harmonia does not build wood frames; higher maintenance | Add → |
A steel or aluminum frame under porcelain or aluminum decking gives a deck that will not burn, top to bottom. Example planning range: steel frame (~$25-35/sf) + porcelain surface (~$40/sf decking-only) is roughly $65-75/sf installed in the SF Bay Area.
** Est. installed (SF Bay Area) = framing material + labor to build the substructure, per sq ft of deck. A planning range, not a quote. Add the decking-only number from the Decking Comparison for a full-deck total.
Steel and aluminum are inherently non-combustible (Class A); wood, even pressure-treated, is fuel. We do not reuse wood framing under a new surface; an existing steel, aluminum, or concrete structure can be, once condition, span and code are confirmed.
Draft for internal use and review. Framing costs vary widely with deck height, span, footings and site. Confirm current pricing, load tables and local code (and WUI listing) before publishing or quoting.