Large-Format Porcelain Spec Sheet for Architects

If you are writing a CSI spec for Laminam, Neolith, or Dekton on a Miami residence, the standard 09 30 13 boilerplate will not protect the project. Gauged porcelain panels at 1620 × 3240 mm sit in a different tolerance class, and Miami’s substrates — post-tension condo slabs, salt air at the curtain wall, association rules on wet-area work — add clauses your specifier won’t find in a national master.

This is a working large-format porcelain spec sheet for architects: the section structure, the clauses that matter, and the Miami addenda we ask the spec writer to add on a Brickell, Coral Gables, or Key Biscayne project. Written from the install side. The point is to keep the slab on the wall, the joint at 1.5 mm, and the warranty intact. For the interior-design counterpart — the four design decisions that move the install timeline by a week or more — see our working with a tile installer: a designer’s guide.

What “large-format porcelain” means in a CSI spec

Large-format porcelain is a gauged porcelain tile panel — 1200 × 2400 mm or larger, 6, 12, or 20 mm thick — installed as walls, vanity surrounds, floors, and cladding. The largest residential sizes are 1620 × 3240 mm from Laminam and 1500 × 3200 mm from Neolith. Cosentino Dekton runs to 1440 × 3200 mm.

Under CSI MasterFormat, the panel sits in Section 09 30 13 — Ceramic Tiling, which was rewritten to absorb gauged porcelain panels (GPP) and gauged porcelain tile panels (GPTP). If your master is older than 2018, it still reads as a small-format ceramic spec. The clauses below are the ones the spec writer needs to add or rewrite.

What changes when the panel exceeds 5 ft

A 12 × 24 in tile and a 1620 × 3240 mm panel are both ceramic. The install standards diverge sharply once the long edge passes about 60 in.

Spec axis	Standard tile (≤ 24 in)	Large-format porcelain (≥ 60 in)
Reference standard	ANSI A108.5, A137.1	ANSI A108.19, A137.3
Substrate flatness	1/4 in over 10 ft	1/8 in over 10 ft (≈ 3 mm / 3 m)
Mortar coverage	80% dry / 95% wet	95% wet, full contact, voids ≤ 2 sq in
Trowel direction	Optional	Straight ridges, panel and substrate combed
Joint width	1/16 to 3/16 in	1.5 mm (≈ 1/16 in) dry-joint or per panel mfr
Movement joint spacing	TCNA EJ171 — every 20 to 25 ft	Every 20 ft + at every plane change
Mechanical attachment	Not required	Required when long edge > 5 ft on walls

The substrate flatness clause is the one most architects forget. A floor that meets the 1/4 in over 10 ft standard for 12 × 24 tile will telegraph through a 1620 mm panel within the first three rows. Call out the tighter tolerance and assign responsibility for measuring it. Our floor leveling field method for Miami condo slabs walks through how we map and correct it before the panel arrives.

Section 09 30 13 — clauses to write or rewrite

The clauses below are not a complete master. They are the ones we ask architects to add or sharpen on a Miami residential project.

Part 1 — General

• 1.02 References. Cite ANSI A108.5, A108.19 (gauged porcelain panel adhered installation), A137.3 (panel material standard), and the current TCNA Handbook including detail EJ171F.
• 1.04 Quality assurance. Installer holds a current Laminam, Neolith, or Dekton manufacturer training certificate for the specified panel. For wet areas, require a Schluter-Systems certified installer credential. NTCA Five-Star is a defensible alternate.
• 1.05 Submittals. (a) Panel certifications and shop drawings of every elevation with joint layout and cuts indicated; (b) one full-panel mock-up on the actual substrate; (c) pre-construction meeting with architect, GC, installer, and property manager when the project is in a building.
• 1.06 Delivery, storage, handling. A-frames or panel carts rated for slab weight. Verified delivery path including elevator interior dimensions and capacity. A 1620 × 3240 × 12 mm Laminam panel is roughly 178 lb. The lift plan is the contractor’s.
• 1.08 Project conditions. Concrete moisture below 75% RH per ASTM F2170. Surface temperature 50 to 95 °F at install. For condo retrofits, name building trade hours and elevator reservation per association rules.

Part 2 — Products

• 2.01 Manufacturers. Approved: Laminam, Neolith / TheSize, Cosentino Dekton. Equivalents subject to architect approval. Panel size, thickness, finish, and series by name in the schedule — not in the spec body, since finishes change.
• 2.02 Panel. Gauged porcelain tile panel per ANSI A137.3. Minimum thickness: 6 mm vertical adhered, 12 mm horizontal interior, 20 mm exterior pedestal. Slip resistance per ANSI A137.1: DCOF ≥ 0.42 wet on any walked-on surface.
• 2.03 Setting materials. Polymer-modified mortar per ANSI A118.4 or A118.15 — large-and-heavy-tile (LHT / non-sag) for vertical. Common Miami specs: LATICRETE 254 Platinum, MAPEI Ultraflex LFT, Custom MegaLite. Substitution off the panel manufacturer’s approved list voids the warranty.
• 2.04 Grout and joint. Urethane or epoxy grout to the panel manufacturer’s joint width. Default 1.5 mm dry-joint. ANSI A118.3 chemical-resistant epoxy for wet exterior.
• 2.05 Membranes. Bonded waterproofing per ANSI A118.10, manufacturer-tested with the setting mortar. Schluter Kerdi sheet is the system we install most often in condo wet areas — the assembly logic is in our read on Schluter Kerdi vs sheet membranes.
• 2.06 Movement joints. Pre-formed silicone or polyurethane per TCNA EJ171F, color-matched, sized to panel. Backer rod where joint depth exceeds 1/4 in.

Part 3 — Execution

• 3.01 Examination. Installer measures substrate flatness and reports deviations greater than 1/8 in over 10 ft to the architect before mobilizing. Panel installation does not start over an out-of-tolerance substrate.
• 3.02 Preparation. SLU per manufacturer where flatness is out. Patch, feather, prime. For condo slabs, the F2170 / F1869 moisture sequence is in our moisture testing note for Miami condo slabs.
• 3.03 Installation, walls. Notched trowel per panel manufacturer (typically 1/2 × 1/2 in U-notch in straight ridges). Back-butter every panel. Beat-in with mallet and suction frame. Lift one in ten panels at the start of each elevation to verify 95% contact. Lippage control with Raimondi RLS or MLT clips. Mechanically attach any wall panel with a long edge greater than 5 ft using clips or a stainless kerf-and-clip system per panel manufacturer detail.
• 3.04 Installation, floors. Same trowel and back-butter logic. Movement joints every 20 ft maximum and at every plane change per EJ171F. Honor every slab control joint through the panel field.
• 3.05 Installation, exterior. Drainage slope minimum 2%. Pedestal-mounted 20 mm panels for rooftop decks. Adhered exterior only with manufacturer-tested exterior mortar.
• 3.06 Cleaning and protection. Cardboard and plywood through trade lockup. Final clean per panel manufacturer.

Miami addenda — the clauses we ask the spec writer to add

These do not appear in a national master because they are local. They belong as Section 09 30 13.13 — Miami Project Conditions or as a project-specific addendum.

• Substrate flatness — measured before mobilization. Architect or owner’s rep witnesses a laser-straightedge or rod-and-read survey on the as-found slab. Any deviation greater than 1/8 in over 10 ft is corrected to 1/16 in before panel delivery. Correction is in base scope, not a change order.
• Movement joint at every plane change. EJ171F sets a 20-to-25 ft minimum. In Miami residential, add a sealant joint at every inside corner and at every plane change (slab-to-pony-wall transitions in a Brickell condo bath), regardless of dimension.
• Mechanical attachment for any panel longer than 5 ft on walls. Wet-mortar-only is not acceptable for a 1620 mm panel on a vertical surface in this climate. Specify either a kerf-and-clip stainless system or an approved Laminam / Neolith mechanical hanger detail. This is the clause that protects the architect when the panel debonds at year three.
• Insurance and COI. Installer carries general liability with the building as additional insured. Brickell and Key Biscayne towers require a certificate with specific endorsement language before any slab enters the building.
• Elevator reservation and panel path. A 1620 × 3240 mm panel does not fit a standard residential elevator on its long axis. Confirm freight elevator interior height, pad clearance, and corridor turn radius for the panel on an A-frame. We have walked away from a Coral Gables retrofit where this was missed.
• Hours of work. Most Miami residential associations restrict trade hours to 8a–5p Monday–Friday with no Saturday work. Put it in 1.08 so the schedule is real.
• Salt-air exterior exposure. For oceanfront cladding (Key Biscayne, Sunny Isles, the Beach), specify stainless anchors and clips, marine-grade sealant, and a setting material with documented salt-spray performance. Carbon-steel substructure is not acceptable. The Laminam architectural specifications and Cosentino Dekton specifications publish exterior assemblies you can reference by name.

A spec-writer’s pre-flight before the bid set goes out

Before the section closes, walk this list. It catches the issues we see on bid drawings every month.

1. Panel size, thickness, and a currently-produced finish are specified.
2. Substrate flatness clause is at 1/8 in over 10 ft, with measurement responsibility named.
3. Mortar is specified to ANSI A118.4 or A118.15 by performance; trade names live in the installer’s submittal.
4. Movement joints are called out per EJ171F with sealant type and color logic.
5. Mechanical attachment is specified for any wall panel with a long edge greater than 5 ft.
6. Waterproofing scope is unambiguously in 09 30 13 or in 07 14 13.
7. Condo conditions — COI, elevator, trade hours, association coordination — are in 1.08.
8. A manufacturer-trained installer is required and the certificate is a submittal.

If any answer is no, the bid comes back with an exclusion that costs the owner later.

How this section ties into the rest of the project specs

A porcelain slab spec rarely lives alone. On a Miami residence, it touches 07 13 26 Self-Adhering Sheet Waterproofing for roof-deck assemblies that the porcelain finishes, 04 43 13 Stone Masonry Veneer when the project mixes natural stone with porcelain, and 22 41 00 Residential Plumbing Fixtures — rough-ins must coordinate with panel layout. A drain two inches off the centerline of a 1620 mm floor panel is a layout failure that costs a slab. When all four sections are written by the same hand, the install runs cleanly. The mixed-material logic for stone-and-porcelain vanity walls is in Calacatta vs Nero Marquina.

When The Miami Floors is the right install partner

We work with architects and interior designers across Miami-Dade and Broward — Brickell, Coral Gables, Key Biscayne, Miami Beach, Pinecrest — on residential porcelain slab, stone, and bath scopes. Ivan Herrera personally walks every project before sign-off. The firm is Schluter certified, Schluter-Systems certified, and an authorized installer for Laminam, Neolith, and Dekton porcelain slab work.

Submit the project package — drawings, spec section, panel schedule, site photos — and we will return a marked spec with the installer-side clauses that need to land before bid. The large-format porcelain installation pillar for Miami is the canonical reference, and the field comparison of Laminam vs Neolith vs Dekton covers cuttability and weight-per-crew details a spec sheet does not.

Reviewed by Ivan Herrera, Founder, Schluter Certified Installer, April 2026.