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Ventilated stone facades

The facade leaves as a finished panel, not a slab.

A ventilated stone facade is an engineered rainscreen, not a finish. We deliver the part that decides whether it lasts: the stone, qualified for the wall, machined to the anchor system, quality-controlled and crated per elevation. Bring your own metalwork and crew, or have us carry the whole wall. Either way, we take the stone and its fabrication off your risk list.

Send the elevations Name the anchor system

The principle

What a ventilated stone facade actually is.

An outer stone skin, a drained and ventilated air cavity, and a sub-structure that carries every panel independently of the wall. The joints are open. Rain is screened, not sealed out. This is a rainscreen, and it is why it outperforms adhered or wet-set stone.

Stone is a reservoir cladding: it absorbs rain and stores it, then the sun drives that moisture inward. A wet-set or adhered panel traps that water against the wall. A ventilated cavity does three jobs at once. It drains the water that gets past the open joint. It breaks capillary contact between stone and wall. And it ventilates, sweeping moisture away so the stone dries from behind.

The result is durability the sealed approach cannot reach. In cold, wet climates a ventilated air gap is what prevents freeze-thaw damage to the stone. Across the wall it moderates temperature and pressure. Every panel can be reached and replaced without disturbing the rest. The cavity is not a detail. It is the system.

STRUCTURAL WALL INSUL. SUB-FRAME PANEL AIRFLOW RAIN, SCREENED OPEN JOINT WEEP FLASHING VENTILATED CAVITY · 25 MM MIN VERTICAL SECTION · OPEN TOP + BOTTOM · NTS
Vertical section · cavity, sub-frame, open joint, flashing
  • DrainageWater is managed, not blocked.

    The open joint lets some rain in by design. The cavity drains it, flashing pushes it out, and the wall behind stays dry. A single line of sealant has a long record of failing.

  • ThermalThe wall breathes and dries.

    A ventilated gap (25 mm or more, open top and bottom) lets the stone dry from behind and moderates the inward vapor drive that destroys adhered stone over cooled interiors.

  • LongevityEach panel stands on its own.

    Panels hang from anchors, independent of the backup wall. They tolerate building movement, survive freeze-thaw, and any single panel can be replaced without touching its neighbours.

  • Material fitWe qualify the stone for this wall first.

    A soft, porous stone that looks right indoors can fail on an open-jointed wall in its first season outdoors. When a drawing names one, we say so and re-source a denser, low-absorption look-alike, use the finish as a color lever, and put a real sample in your hand before anything commits.

Two ways we deliver it

Solid panels, or stone honeycomb.

The cladding can be solid stone or a lightweight composite. Both are real natural stone on the face. They trade weight, format and cost against each other, and the right choice depends on the building, not on a preference.

RAIL SOLID PANEL 20–30 MM FACE UNTOUCHED KERF SEAT VERTICAL SECTION · NTS
A · Solid stone cladding

Full-thickness panels on mechanical anchors.

A solid stone panel, typically 20 to 30 mm thick, carried by kerf clips or undercut anchors that engage the edge or the back. No visible fixings on the face. It is the reference system for premium ventilated facades.

  • Kerf clips for edge engagement, undercut anchors for larger or heavier formats
  • The full depth of the stone reads in every reveal and return
  • Thickness sized to the wind load and the anchor, with material left around the kerf
  • Heavier, so panel size and substructure are sized accordingly
STONE FACE EPOXY ALU SKIN CORE BACK SKIN 8 MM TOTAL ≈ 20–28 MM · A FRACTION OF THE WEIGHT OF SOLID STONE EXPLODED BUILD-UP · NTS
Back of a stone honeycomb facade panel: aluminum honeycomb core visible at the edge, thin stone face and interlocking clip plate
Honeycomb panel · core and clip, real build-up
B · Stone honeycomb

A thin stone face on an aluminium core.

A natural-stone face of roughly 8 mm, epoxy-laminated to an aluminium honeycomb core. One slab yields multiple faces, the panel is a fraction of the weight, and large or curved formats become possible where solid stone would be too heavy.

  • A fraction of the weight, so larger panels and lighter substructure
  • Curved and oversized surfaces that solid stone cannot reach
  • More fabrication: two suppliers and a lamination step behind every panel
  • Engagement and edges detailed for a composite, not a solid section

The trade is simple. Solid stone gives you depth, mass and the longest track record. Honeycomb gives you a fraction of the weight, larger formats and reach, and on a high-wind wall its low mass is an asset. On a salt-blasted oceanfront we detail the aluminium core for chloride exposure or choose solid stone on stainless: high wind and salt are two different questions, and we answer both. We will tell you which one the building wants.

Two ways to bring us a facade

Take the stone and our guidance, or hand us the whole wall.

The same stone expertise sits behind both. The only question is where you want the line. Bring your own metalwork and install crew and let us qualify and machine the stone, or have us carry the entire engineered system as a single source. Most projects start at the first and escalate to the second when they want one number for the wall.

Option A · Stone & system guidance

The qualified stone, machined to your system.

We qualify the stone for the wall, machine the panel to your anchor system, and tell you which system the building actually wants. You, or your facade contractor, bring the sub-structure, the anchors and the install.

  • Stone screened for the exposure against the ASTM methods
  • Panels machined to your kerf, undercut or dowel system
  • System guidance: the right anchor and metal for the wall
  • You own the metalwork and the install
How the supply line works
Option B · The whole wall, one source

Everything in A, plus the system itself.

When a project wants one partner from the bare structure to the last fixed panel, we carry the engineered stainless sub-structure, the as-built 3D scan, on-site technicians, and the testing and approval submissions the building department needs, coordinated with accredited laboratories and our engineering partners.

  • Engineered stainless sub-structure, supplied
  • As-built 3D building scan before a panel is cut
  • Technicians on site for the install
  • Testing and certification, coordinated for you
See the single-source scope

Option A · Where we fit

We deliver the finished panel. You own the wall.

We hand over a machined, inspected, crated panel, and the substructure, anchors and on-site install stay with your team. That is the panel-supply tier. When a client wants a single source for the entire wall, we carry the whole engineered system too: the full scope is further down.

ElementWhat it coversOwner
Stone selection Block chosen at the quarry, read for vein, tone and the flaws a photo hides. Alimonta
Panel fabrication Cut to size, faces and kerfs machined to your anchor system, finished to spec. Alimonta
QC & crating In-person quality control, then crates mapped and zone-tagged per elevation. Alimonta
Anchor system Kerf clips, undercut anchors and their engineering. In this tier we machine to it; supplied by us only on the single-source scope below. Your installer
Substructure Brackets, rails and the cavity build-up fixed back to the building. Your installer
On-site install Setting out, hanging the panels, sealants and final tolerances on site. Your installer

We machine the kerf and the panel profile to your anchor system, so we need to know that system before the stone is cut. Tell us the anchor and we build the panel to fit it.

The systems we build to

The four ways America hangs stone. We machine to every one.

Whether your installer brings the sub-structure or we supply the whole system, the kerf, the undercut bore and the edge tolerance are cut into our stone to a dimension the assembly leans on. So we speak the systems the U.S. market actually specifies today. Name yours, and the panel arrives ready for it. All of it in real natural stone, not stone-look porcelain.

Ventilated natural-stone facade under installation: stainless edge clips bolted to the backup wall, engaging the kerf on the top and bottom edge of each stone panel inside the open joint, with nothing fixed through the face
Edge clips engaging the panel kerf at each open joint · ventilated stone facade under installation
Stainless steel sub-structure brackets set out along the backup wall on site, forming the ventilated cavity before the stone panels are hung
Stainless sub-structure set out on the backup wall · the ventilated cavity, before the stone is hung
SHEATHING MINERAL WOOL 1 1/4 IN TOP ANCHOR ADJUSTABLE MULLION · 16 IN O.C. MAX T-ANCHOR · EACH PANEL HANGS ALONE 3/8 IN OPEN JOINT STARTER ANCHOR AIRFLOW THERMAL-BREAK BRACKETS 16 IN O.C. H · 24 IN V CAVITY + SUB-FRAME S1 · VERTICAL SECTION · NTS
S1 · Kerf rail on adjustable mullions

The American workhorse.

Continuous kerf extrusions ride on adjustable vertical mullions, hung from thermally broken brackets. Each panel is carried on its own kerf, top and bottom, so a single stone can be set, removed or replaced without touching its neighbours: the non-sequential install U.S. facade crews price for.

Backup
Steel stud + sheathing or concrete, with continuous insulation inside the code
Signature
Panel-by-panel replacement, thermally broken brackets, fast set-out
Our part
The kerf milled to the extrusion, edge tolerance the clip can trust
AGRAFFE + LEVELING SCREW HORIZONTAL RAIL UNDERCUT · LOAD IS MECHANICAL NOTHING THROUGH THE FACE 30 MM NOM. BLIND BORE BACKUP SUB-FRAME DETAIL · 3× S2 · SECTION DETAIL · MIN 4 ANCHORS PER PANEL · NTS
S2 · Undercut back-anchor on agraffe rail

The hidden fix for large formats.

An expansion sleeve spreads into a flared, blind bore on the back of the panel: the hold is mechanical, the face is untouched. Panels hang on agraffe plates with leveling screws over horizontal rails. It is what U.S. architects specify when the format grows and the joints have to stay empty.

Backup
Any: the rails float on adjustable brackets, stud to concrete
Signature
Blind fix, minimum four anchors per panel, pull-out proven per ASTM C1354
Our part
CNC undercut bores to the anchor maker's drawing, panel by panel
STONE FACE EPOXY ALU SKIN CORE BACK SKIN 8 MM INTERLOCKING CLIPS · SHOP-BONDED HAT CHANNEL ON THE BACKUP PANEL ≈ 1/3 THE WEIGHT OF SOLID ≈ 25 MM HANG DETAIL S3 · BUILD-UP + HANG · NTS
S3 · Stone honeycomb panels

Real stone at about a third of the weight.

A natural-stone face around 8 mm thick, epoxy-laminated to an aluminium honeycomb core, built through the Verona specialist shops that also make lightweight fireproof panels for aviation and marine work. The panel weighs a fraction of solid stone, so formats grow, the sub-structure lightens, and the route into hurricane-zone walls opens: it is the lightweight skin U.S. high-wind projects reach for.

Backup
Stick-built or unitized, including high-velocity wind zones
Signature
Large formats, low mass, one slab yielding multiple faces
Our part
Stone faces sawn and calibrated, the lamination run through one chain
CMU BACKUP FLOOR SLAB SPLIT-TAIL ANCHOR · KERF SET FULL-THICKNESS STONE BEARING ON THE RELIEVING ANGLE SOFT JOINT · ROD + SEALANT S4 · SECTION AT THE FLOOR LINE · NTS
S4 · Handset on relieving angles

The classic American wall. Still everywhere.

Full-thickness stone bearing on relieving angles at every floor line, tied back with stainless split-tail anchors set in kerfs, four per panel at the quarter points, a soft joint under each angle to let the building move. The oldest curtain in the U.S. market, and still what much of its masonry-backed mid-rise is built on.

Backup
CMU or concrete, an angle at each floor line
Signature
Mass, depth in every reveal, a century of track record
Our part
Kerfs, anchor slots and beds cut to the anchor schedule

Three metals, chosen by the building, not by habit.

The sub-frame and the fixings come in three metallurgies. Which one belongs on the wall is decided by the load and the exposure, never by what is cheapest in the yard.

  • AluminiumThe default rainscreen sub-frame.

    Extruded rails and brackets, light and corrosion-stable, the workhorse of the ventilated cavity. The substructure most facades hang the panels from.

  • Stainless 304When the load or the span climbs.

    Brackets and anchors step up to austenitic stainless for higher pull-out and a service life that coated carbon steel cannot match. Bare carbon steel never carries a facade unprotected; where a galvanized relieving angle is used it is isolated from the stainless and the stone.

  • Marine 316LWhen the exposure demands it.

    For the most aggressive salt exposure, brackets, anchors and fixings step up to 316L for resistance to chloride pitting. The grade follows the engineer's calculation and the wall, not a blanket rule.

Corrosion, not the stone, is the first failure mode on a facade. So the metal follows the exposure, and on the coast dissimilar metals are isolated to stop galvanic corrosion at the source.

The standards the wall is designed and proven against.

Every acronym below is a test or a design method a U.S. engineer will recognize. We design to them from the first cut sheet, and on the single-source scope the testing is coordinated with accredited laboratories.

ASTM C1242The design guide for exterior stone anchoring: selection, sizing and installation of every anchor on the wall.
ASTM C1354The anchor pulled to failure in the project's real stone. The number that sizes how many anchors each panel needs.
ASTM E330 / E331The assembled wall under wind pressure, then under driven water. Deflection and leakage, measured, not assumed.
NFPA 285Fire propagation of the whole wall assembly. Why the cavity insulation is mineral wool, not foam.
Miami-Dade NOAThe hurricane-zone acceptance path: impact and pressure cycling. Coordinated with accredited labs where the project requires it.

Option B · Single source, on request

Or we deliver the whole wall, not just the stone.

When a project wants one partner from the bare structure to the last fixed panel, we carry the entire ventilated system as a single source. We survey the building, engineer the structure to the wind load and the seismic code at a safety factor of 5, supply the stainless metalwork, machine the stone, test the assembly with accredited partners, coordinate the certification your authority requires, and put technicians on site for the install. One source, one responsibility, one number.

Metal structure, supplied

Not just matched to your anchor: supplied. We supply and ship the stainless sub-structure itself, AISI 304 or 316L marine grade. Mullions, rails, edge-retention clips and the M8 anchors, sized by the engineering to the wind and the wall.

Building survey & scan

We scan the structure as-built, on site, before a panel is cut. The survey becomes the panel grid: every reveal, opening and tolerance reconciled to the building that exists, not the one on the drawing.

Technicians on site

Our technicians travel to supervise setting-out and installation. The partner team that machined the panels stands behind the crew that hangs them, so a detail decided in Verona is read the same way on the wall.

Laboratory testing & certification

On the full single-source scope we coordinate the testing and the approval submission to the standard your jurisdiction enforces: ASTM E330 wind load, E331 and E283 water and air, AAMA 501.1 dynamic water, and in Florida's HVHZ the Miami-Dade NOA and TAS impact path. We run it with accredited laboratories and our engineering partners, so the wall is tested and submitted, not just claimed.

Survey to install, one chain.

Survey & scan Engineering & calc Shop drawings & cut tickets Metal + stone fabrication Test & certify Ship & install supervision
BACKUP WALL VENTILATED CAVITY M8 ANCHOR AISI 304 / 316L MULLION + RAILS EDGE-RETENTION CLIP STONE PANEL · 30 MM EVERY PANEL HELD AT THE JOINT, NOTHING THROUGH THE FACE STATIC CALC · SAFETY FACTOR 5 WIND + SEISMIC, BY THE ENGINEER WALL SECTION · SUPPLIED STAINLESS SYSTEM · NTS
Wall section · supplied stainless mullion, rail and edge-retention clip · engineered at safety factor 5

We present this as one capability and one point of contact. You brief us once; the survey, the metal, the stone, the tests and the crew are ours to coordinate, not yours.

Selecting the stone

A facade stone is qualified, not just chosen.

On a facade the stone is held at points and flexes between anchors under wind. The risk is not aesthetic, it is structural. We screen a material against the way it actually fails outdoors: bowing, freeze-thaw, low flexural strength, water absorption. We speak to the method and the tests, never to invented numbers.

C880Flexural strength, real thicknessHow the panel flexes between anchors under wind, tested at the thickness that ships. The number the engineer sizes the anchor against, and the one we want after environmental cycling, not just when new.
C99Modulus of ruptureThe class-acceptance flexural value used to screen a material before it earns a facade. Read alongside C880, never instead of it.
C97Absorption and densityThe first number we read. Low absorption means most outdoor risks, freeze-thaw and salt among them, quietly fall away. High absorption means durability has to be proven, not assumed.
C1528Exterior dimension-stone useThe guide for selecting stone for exterior application: matching the material and finish to the exposure, the climate and the way the panel will be supported.
BowingThermal hysteresis (marble)Calcitic marble can warp permanently and lose much of its flexural strength under repeated heat-and-water cycles. For an exposed marble facade this is the gate that is never skipped. No pass, no facade.
C1354Anchor pull-out in the stoneHow much load a single clip or anchor holds in the kerf or hole before the stone gives. It sizes how many anchors a panel needs, and the safety factor that protects the wall.

Coastal detailing is a different conversation.

On the ocean, salt drives the spec. Exposed brackets, anchors and fixings are specified in stainless to the engineer's calculation, 304 or 316L by the exposure, and dissimilar metals are isolated to kill galvanic corrosion at the source. We read the test report against the real block and the real finish, because the stone that ships has to be the stone that was tested, not the type in general.

LOAD, TO FAILURE LOAD CELL RESTRAINT ANCHOR IN THE KERF THE NUMBER THAT SIZES THE ANCHOR COUNT ASTM C1354 · ANCHORAGE IN THE STONE · NTS
ASTM C1354 · anchor pull-out in the stone

Why we are different

We close the panel chain. Most stop at the slab.

A facade panel runs through two suppliers: the quarry that yields the slab and the workshop that machines or laminates it. Most brokers hand you the slab and leave the rest to you. We hand you one finished panel.

Quarry front with sawn stone benches, two workers reading the face before block selection
Quarry face · reading the block before it is cut
01

We pick the block at the quarry.

We get on a plane, read the quarry face, and choose the block in the light it was cut in. On honeycomb one block yields many faces; on solid stone we cut panels from block slices, so a facade of hundreds of panels reads consistent and costs less than large-slab pricing. We carry the yield risk so you do not.

02

We close the two-supplier chain.

Quarry slab on one side, panel fabrication on the other. We run both and hand over a single finished panel, not a commodity slab and a problem.

03

Machining and QC, in person.

Faces, kerfs and profiles cut to your anchor system, then checked by hand before anything leaves: thickness, finish, vein continuity and lot consistency, documented.

04

Crated as a kit, per elevation.

Panels arrive zone-mapped to the elevation grid, so the crew opens a crate and finds the run it needs. Install order, not transport order.

ZONE A1 ZONE A2 ZONE B1 R.O. ELEVATION NORTH CRATE 07 RUN A2-R2 THE CREW OPENS A CRATE AND FINDS THE RUN IT NEEDS ELEVATION · ZONE-MAPPED CRATES · NTS
Elevation grid · zone-mapped, kit-per-elevation crating

Pricing & take-off

From net facade area to raw slab, then to a panel price.

A facade is priced as a lump sum per finished panel, with freight separated, never as a flat rate that hides the fabrication. The take-off works backward from the wall to the stone that has to be quarried, on real sourcing rather than theoretical rates.

01 · Net areaNet facade area

The visible wall area to be clad, taken off the drawings and confirmed before anything is quoted.

02 · To raw stoneYield to raw slab

Net area converted back to slab to order, accounting for the yield of the chosen panel build-up and how the stone is worked.

03 · Loss factorsWaste and block quality

Fabrication waste plus the loss factor for that material and block, so the order covers what the workshop will actually consume.

04 · Lump sumPrice per panel, freight apart

Built up as a lump sum per finished panel. Ocean and inland freight stay separate line items, sized to real weight and format.

Honeycomb is light, so the constraint is usually crate volume and panel format, not weight or the container limit. Solid stone is the opposite. Either way the freight is sized to the real load, and the panel price stands on a sourcing route we can stand behind, not a rate sheet.

How the take-off works

Real material

Documented from quarry to crate.

No finished-project photos. The work belongs to the contractor we built it for. What we show is material and process: the block, the face, the fabrication, the anchored facade.

Grey stone quarry, block extraction
Quarry · block extraction
Stone block rigged with steel cables for handling in the yard before sawing
Block rigged for the saw
Vein-cut travertine slab hanging from an overhead clamp lifter in the workshop
Overhead lifter · workshop
Operator checking the height of a stone panel with a tape measure before release
QC · height check before release
Open export crate with cut-to-size stone packed on edge and separated by foam
Crated on edge · foam separated
20 ft container loaded front to back with crated stone
20 ft, loaded front to back
Case study Ultra-white exterior, validated before a block was cut Read the case

Facade questions

Asked before every facade. Answered here.

What is a ventilated stone facade?

An engineered rainscreen: an outer stone skin, a drained and ventilated air cavity, and a sub-structure that carries every panel independently of the backup wall. Open joints screen rain rather than seal it out; the cavity drains, breaks capillary contact and dries the stone from behind. In freeze-thaw climates it outperforms adhered or wet-set stone.

Solid stone or honeycomb: which one?

Solid stone gives depth, mass and the longest track record. Honeycomb gives a fraction of the weight, larger formats, and the lightweight route hurricane-zone walls take. The building decides, and we tell you which one it wants.

What anchor systems do you machine to?

The four the U.S. market specifies today: kerf-rail on adjustable mullions, undercut back-anchors on agraffe rails, stone honeycomb on interlocking clips, and handset walls on relieving angles with split-tail anchors. Name the system and the panel arrives ready for it.

What ASTM tests qualify a facade stone?

C880 flexural at real thickness, C99 modulus of rupture, C97 absorption and density, C1528 exterior selection, C1354 anchor pull-out in the stone, and for calcitic marble a bowing test for thermal hysteresis. No pass, no facade.

How much does a ventilated stone facade cost?

It is priced as a lump sum per finished panel with freight as separate lines, never a flat rate. Stone, panel build-up, anchor machining and format drive the number. European sourcing has a real floor: when a commodity target cannot be met, we say where our range starts. The take-off that fixes the quantity comes back in 24 to 48 hours.

What do you supply, and what stays with the installer?

Baseline: we supply the finished panel, selected, machined, QC'd and crated; the anchor engineering, substructure and install stay with your team. On the single-source scope we carry the whole engineered wall: survey and scan, stainless metalwork, testing coordinated with accredited laboratories, and technicians on site.

The next step

Send the elevations and the anchor system. We will build the panel.

Send the elevations
michele@alimonta.com +1 (917) 983-6312 WhatsApp Verona, Italy