BANARTA
For a stud wall, choose board thickness from the permitted stud spacing; for a solid wall, choose it from the approved bonding method and the finished wall level. A thin board backed by a continuous wall and a board spanning an open frame do different jobs. Increasing thickness does not correct loose framing or an unstable substrate.
What do 12.5 mm and 19 mm actually mean?
A published example makes the relationship clear. Schluter specifies KERDI-BOARD at a minimum 12.5 mm for studs at 406 mm centres, and 19 mm for studs at 610 mm centres. The wider unsupported span needs a thicker board in that system.
| Support example | Published KERDI-BOARD minimum | Meaning for purchasing |
|---|---|---|
| Studs at 406 mm centres | 12.5 mm | Order a board qualified for that spacing, with its fixing details. |
| Studs at 610 mm centres | 19 mm | Do not carry the thinner-board choice across to a wider span. |
| Continuous solid backing | Determined by the selected bonding method | Start with substrate condition and final wall level rather than copying a stud-wall thickness. |
These are Schluter system examples, not Banarta installation ratings. For Banarta supply, send the actual stud spacing or solid-wall detail with the required sheet size. This gives the supplier a concrete configuration to review rather than an unspecified request for “bathroom board”. Compare materials first in our XPS backer board vs cement board guide.
Separate the wall conditions
| Wall condition | Information needed before selecting a board |
|---|---|
| Solid mineral wall | Surface condition, flatness and the specified bonding method |
| Timber or metal studs | Stud spacing, board orientation, edge support and fixing schedule |
| Uneven existing wall | Survey and approved correction method before board installation |
| Fixtures or accessories | Backing or anchors that transfer loads to suitable support |
Do not use a board as an assumed remedy for an unstable wall. Identify movement, damaged substrate or inadequate support before ordering. A thicker panel may still be unsuitable when the assembly is outside the manufacturer's documented use.
Ask for the thickness-to-support relationship
For a framed wall, ask the supplier to identify the permitted thickness and support spacing together. Include the position of joints and how cut edges will be supported. Record fastener and washer requirements from the selected system; generic fastener dimensions should not be copied from a competing brand.
For a solid wall, confirm whether the intended method requires full bedding or another specifically approved arrangement. The mortar or adhesive must be suitable for both the wall and the board surface. A product called “tile adhesive” does not automatically establish compatibility with every backing or substrate.
Coordinate the finished wall plane
A useful drawing shows substrate, board, bonding layer and finish. As a hypothetical coordination example, a 12 mm board, a 4 mm finished bonding layer and a 9 mm tile add 25 mm in front of the reference plane. Actual layer depths and permissible board thickness must come from the chosen system, not this example.
Check that the resulting plane meets door linings, shower fittings, adjoining finishes and recessed components. If the board thickness changes, update these junctions as well as the quantity schedule. Do not treat a nominal trowel notch as the final adhesive layer thickness.
Keep fixture loads out of a vague board claim
Handrails, folding seats, basins and other fixtures need their own support detail. Mark them on the wall drawing before the board conceals the framing. The foam board's compression result alone is not a fixing capacity or permission to mount a loaded fixture into it.
Approve a wall schedule
- Room and wall reference, wet or dry exposure.
- Substrate type and support spacing where relevant.
- Board product, thickness, orientation and sheet size.
- Tile type, dimensions, weight and fixing materials for system review.
- Openings, cut edges, fixture backing and adjoining finish levels.
- Document revision and who approves unresolved details.
Use Banarta's tile backer board range to begin the enquiry. Read the wet-area detail checklist for joints and penetrations, then send the wall schedule for configuration and document confirmation.
Reference and limits
Schluter's KERDI-BOARD documentation illustrates that support arrangement and application determine system requirements. Its thicknesses, fixings and approvals apply to that system and cannot be transferred to Banarta boards.
