How to create tops for bathrooms and kitchens with Casalgrande Padana porcelain stoneware slabs

Oct. 20, 2020

How to create tops for bathrooms and kitchens with Casalgrande Padana porcelain stoneware slabs

Casalgrande Padana porcelain stoneware slabs have always been synonymous with versatility, creativity and ease of installation. The elegance of the surfaces and the refinement of the material effects, combined with the unparalleled technical performance, provide a variety of solutions suitable for all purposes, even for the most demanding designers.

Formats and thicknesses

The most commonly used formats for creating porcelain stoneware tops for bathrooms and kitchens range from 75.5x151 cm to 88x176 cm, from 90x180 cm to 90x270 cm up to 118x236 cm, 118x258 cm, 118x278 and 160x230 cm, with thicknesses ranging from 12 to 10 mm, down to thin thicknesses of 6 and 6.5 mm. The thickness of the ceramic slab to be used in the top must be selected appropriately according to the geometry of the cut, the characteristics of the support where it will be installed and the use of the furniture in question. In addition, all these formats are supplied in a rectified version, except for the 160x320 cm format with a thickness of 12 mm, which is supplied in an unground version: normally, in fact, the first few centimeters of the edge are deliberately“contoured” to optimize the organization of the cut.

Designing the shape: recommendations and suggestions for use

In order to machine Casalgrande Padana ceramic slabs in the best possible way, there are a few tips to consider:

Minimum distance from the edges

Holes, openings and channel cuts must be made at an appropriate minimum distance from the edge (dmin), inside which the slab should not be machined. It is difficult to define a value for this minimum distance, since it depends on the stress levels and the overall amount of machined surface of the slab. As a guideline, a minimum distance from the edge of no less than 7 – 8 cm can be kept. If this distance cannot be maintained due to overly complex geometry, it is recommended to divide the geometry into square or rectangular submultiples.

Distanza minima dai bordi
Distanza minima dai bordi

Reinforcement with lath

If the items of furniture include large openings and the slab has to be extensively drilled and machined, the geometry and layout of the cut itself may require the application of a safety lath on the back of the slab. If not explicitly requested at the time of ordering, the lath can be applied to the back of the slab in the workshop using special machinery, using high quality epoxy resins and a glass fibre lath of an appropriate weight.

Rounding of corners

As a general rule, perfect 90° angles are not recommended with either waterjet cutting or disc cutting. The corners of internal rectangular shapes, commonly used for built-in steel fixtures (sinks, hobs, etc.) must necessarily be rounded. The rounding radius must never be less than the thickness of the slab. The same approach can also be used in the case of corners with different angles (obtuse or acute angles). Circular incision at the corners, in the case of burr cuts, must always be performed before any other linear disc cutting.

Joints between ceramic and other materials

Whenever the top ceramic top has to be combined with other surfaces (items of furniture, the walls of the room, metal elements, doors and windows, etc.) and subsequent elastic grouting is required, it is important that the space between these surfaces and the ceramic is appropriately defined, taking account of: the expansion coefficients of the elements involved (for porcelain stoneware, 6x10-6), any movement and/or deformation that the elements must withstand and the elasticity of the grouting.

Design layout for ceramic tops

When creating a top for a bathroom or a kitchen with Kontinua large format porcelain stoneware slabs, the type and shape of the furniture to be made, the aesthetic and chromatic effect of the slab to be used and the type of structure available must all be taken into account.

In any case, ceramic merely performs a cladding function and cannot be used for “structural” purposes. During the design stage, depending on the expected levels of use, it is advisable to anticipate and therefore reduce any critical issues arising from improper use of the ceramic top, including the following measures:

- geometry of the top: diagonal cuts to join different portions are generally not recommended. Instead, it is always preferable to make straight cuts, for preferably square and rectangular slab portions that do not have considerable imbalances in the reagent section. It is therefore preferable for particularly complex geometries to be broken down into rectangular submultiples to be joined during assembly.

Geometria del top
Geometria del top

- suspended parts: if the furnishings include portions that are not fully supported by the furniture support or “suspended” projections, an appropriately secured and supported slab with a thickness of 12 mm is recommended. The geometry, type, number and nature of the supports bearing the load of this slab must be defined during the design stage according to the maximum use expected during the life of the furniture.

Installation of sinks and metal fixtures

For the installation of sinks or other metal elements in a channel cut in the slab, the edges should be shaped according to the pre-established aesthetic result. The types of joining are as follows:

- upper top joining: this is the simplest and most immediate solution and does not require particular attention in creating the channel cut because the cutting is completely hidden. It is recommended not to “hang” the metal fixture on the worktop, but instead to fix it to supports underneath to offload the weight appropriately.

- lower top joining: this consists of hooking the fixture chemically and mechanically to the back of the slab. In this case, it is normally recommended not to hang the metal fixture on the worktop, but instead to fix it to supports underneath to offload the weight appropriately. In addition, it is strongly recommended to reinforce the back of the slab when lower-top finishes are required. It is also advisable to bevel both edges to avoid chipping when using the furniture.

- level top joining: this finish, which is particularly appreciated from an aesthetic point of view, entails removing a portion of the surface of the slab since the metal fixture and the top surface of the slab are at the same level. This removal must never exceed 20% of the total thickness of the slab (excluding any reinforcement behind it). As in the previous case, it is recommended not to hang the metal fixture on the worktop, but instead to fix it to supports underneath to offload the weight appropriately. The space between the slab and the metal fixture, as well as the elastic filling material, must be properly defined during the design stage according to the reciprocal thermal expansion of the materials involved (for porcelain stoneware, 6x10-6).

Finishing the edge

The elegance of Casalgrande Padana porcelain stoneware slabs, used as cladding for furniture, is further enhanced if the contours are machined properly. The choice of edge is purely aesthetic, but it is necessary to have suitable machinery and cutters.

The chromatic effects of the surface of the slab are not as evident on the inside and therefore the type of edge finish should be chosen according to this aesthetic feature. In any case, depending on which type is chosen, it is possible to roughen, satinize or sand the edge. Suitable automatic machines exist for this purpose with diamond grinding wheels or abrasive pads to be mounted on backing pads for angle grinders or screwdrivers, with the abrasive grain differentiated according to the degree of finish required. In both cases, always refer to the supplier's instructions to identify the optimal operating parameters (number of revolutions, abrasive grain types, optimal sequence of grain types). For furnishings with a high risk of chipping during their useful life, finishes with rounded edges are preferable.

BEVELLED STRAIGHT EDGE
DOUBLE-BEVELLED STRAIGHT EDGE
FULL BULLNOSE
HALF BULLNOSE
MITRE CUT
ROUNDED QUARTER
ROUNDED STRAIGHT EDGE
DOUBLE ROUNDED STRAIGHT EDGE
¼ STRAIGHT EDGE
WATERFALL EDGE
BEVELLED BULLNOSE

Checking the installation support

The supporting furniture where the slab is going to be installed must have all the necessary characteristics to meet the requirements deriving from its intended use and must be chosen specifically depending on: the geometry of the furniture, the expected levels of use of the furniture, requirements of durability in relation to the environment where the furniture will be located, and the aesthetic characteristics of the environment, if there are visible or semi-hidden elements.

Precisely because of the variability of the type and nature of the substrate, a minimum recommended thickness of the substrate cannot be known in advance. This value must normally be recommended by the supplier of the substrate. In any case, since the finishing ceramic plays an exclusively aesthetic role, it does not have any structural value: the distribution of loads deriving from its use and the support for its own weights deriving from the assembly of the furniture must be performed by real structural elements.

Contouring

If the geometry of the furnishing to be created requires it, first of all contour-cut the slab according to the desired measurements. The contouring can be performed with any cutting and processing equipment available (waterjet, bridge cutters, etc.). In general, contouring of the slab is always recommended, also for geometric optimization of the cuts to be performed.

Handling the machined slab

Handling represents one of the most critical and “stressful” phases for the processed slab. It should be borne in mind that, in relation to the size of the area removed during machining, handling can cause high levels of loading/stress on the item, which could break and make the work carried out pointless.

Therefore, the following precautions should be taken:

- eliminate any unnecessary movement, both from the work station to the storage area and from there to the installation site;

- store the machined slabs on a stable support that is capable of absorbing any type of vibration present in a normal workshop and which does not cause excessive flexural or torsional stress;

- if the portion of slab to be removed/machined is considerable and the handling involves several steps, it is advisable to plan and provide a reinforcement lath to be applied on the back of the slab;

- all handling operations of the cut slab must be carried out cautiously, slowly and in such a way as to avoid sudden swinging or vibration of the slab;

- during transport from one location to another, the machined slab must be kept adequately rigid to avoid flexural and torsional stresses. This can be done by providing temporary wooden frames or trays with a rigid and resistant platform for flat transport. If transported vertically, position the part of the slab with the various portions cut out at the top;

- protect the edges of the slab with edge-protection profiles made from rubber or other soft material.

Movimentazione della lastra lavorata
Movimentazione della lastra lavorata
Movimentazione della lastra lavorata

Installation

The machined ceramic slab can be glued to the substrate as long as it meets the fundamental requirements of robustness and flatness and is able to withstand the expected loads for which it was designed. Installation on non-planar, non-resistant substrates or which are not designed for the end use may result in breakage and damage to the machined slab. The choice of adhesive to bond the slab to the supporting surface depends on the nature of the support itself and must guarantee compactness of the adhesive layer to withstand the designed loads. This layer must also have a certain degree of elasticity to allow the physiological differential movements between the ceramic and the support that also occur during use. If the slab is installed on supports made up of several parts (for example, kitchen or bathroom wall units), perfect flatness of the supporting surface must be guaranteed, especially around the perforated/machined parts of the slab. In the case of kitchen or washbasin tops made with several machined slabs that have to be positioned at the same level, it is advisable to provide a sufficiently elastic seal (e.g. silicone) to allow for any differential movements.

Installazione
Installazione

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