Maestral® is a large-formatted terracotta cladding (up to 300 x 1520 mm and up to 410 x 1400 mm) with open horizontal joints.
It is available in ten colours and four finishes (smooth, sanded, ridged and grooved).
CSTB Technical Approval no. 2/10-1428.
H = Height, L = Length, (*for other lengths, please contact us); Th. = thickness ** for a 1 cm horizontal joint and for a 2 cm vertical joint *** with the addition of an extra upright (see Technical approval). > Ability to resist earthquakes: can be used in zones Ia, Ib and II for class A, B and C buildings and in zones Ia and Ib for class D buildings. > Resistance to frost: Maestral® products meet the NF EN ISO 539.2 frost resistance standard.
The cladding process is based on double-wall terracotta products, supported on a vertical metal or wood framework secured to the main structure with insulation installed behind the framework.
Each product is fixed using special stainless steel bracket clips, fitted with closed cell foam pads to increase the product’s grip. The supporting profiles include a protruding spine between the vertical joints, which has an aesthetic function and protects against exterior elements.
Miscellaneous accessories not supplied by TERREAL (in italics in the diagrams): thermal insulation, fixing brackets, metal and PVC profiles for fixing flashing and trims, screws, fixing anchors.
Maestral® installations must conform to the requirements of CSTB Technical Approval no. 2/10-1428.
Fitting onto a concrete or masonry structure, covered with a vertical framework, must comply with the rules given in CSTB specifications nos. 3316/3422/3585 (wooden framework) – or no. 3194/3586 (metal framework, with design restrictions).
This framework is made up of special aluminum profiles, fixed to standard brackets or directly to the wall, or to wooden battens, themselves fixed to brackets. Fitting to a metal framework is also possible.
In a thermal insulation situation, the brackets are laid out beforehand in a staggered pattern on either side of the profile or batten. Where fitted directly (with no insulation under the cladding), fixing is done by anchoring through the wings of special aluminum profiles.
The spacing of these fixings, not supplied by TERREAL, must be done as required following a technical survey, taking account of thermal and mechanical requirements (strength of the anchors, wind, and seismology).
Maestral® products are fitted from the bottom upwards; two standard clips are slid on first in the two top corners of the Maestral® product, before the bottom of the product is positioned on the previously positioned bottom clips. The product is then pushed back against the profile.
Before screwing the top clips to the profi le with two 5.5 mm diameter, selftapping stainless steel pan head screws, or a wood screw where fixing on to a wooden framework, the clips must be height adjusted to comply with the 21, 31 or 42 cm spacing and be spaced horizontally against the central core of the profile. Maestral® may easily be cut vertically at critical points (15 cm minimum) using a diamond-tipped saw, lubricated with water.
Diagram 1 : vertical cut, standard fit
Diagram 2 : horizontal cut, standard fit
Diagram 3: horizontal cut, direct fit
*theoretical dimensions at close tolerances for terracotta
Using a laser or spirit level, draw a horizontal reference starting line for fitting the profiles. The starting point is determined from the layout drawing.
Mark the spacing of the profile according to the required vertical joint. Adjust for plumb, using spacers if necessary to avoid distorting the support profile.
Positioning the starting clips is done from the bottom of the profile positioned on the horizontal reference (2 self-tapping screws per clip).
Place the left and right standard clips on the Maestral® and position the products on the lower clips.
Fix the clips to the core of the profile with self-tapping screws, using the spacing (210 mm, 310 mm or 420 mm).
Repeat the above operation up to the required height: position left and right standard clips on the Maestral®, put it in place on the lower clips and fix one clip and then the other.
Position the upper clips for the final piece of Maestral®. Move aside the next piece along, to fix the visible clip and then do likewise for the other upper clip.
Position the Maestral® with the vertical joint required.
The Maestral® fixing system makes it possible to fit the product vertically, where each product is supported on its side by a standard clip. The clips at the bottom are offset for a horizontal joint; the vertical joint, on the other hand, is reduced to 6 mm. This type of fitting makes it easy to clad curved surfaces.
A perforated metal rail is fixed to the support beforehand, to protect the insulation while maintaining ventilation via the air gap. This profile is optional when fitting direct (no insulation).
The first row of Maestral® must be supported at the bottom not by standard left and right clips but by bottom clips used on both the left and right hand sides. Bottom clips are fixed close to the bottom of the vertical profiles.
At the top, the Maestral® system must be protected by a water run-off arrangement, sealed to the support, covering the products and overhanging by at least 20 mm (ventilation holes to be sized according to the height of the cladding).
Fixing the top corners of the Maestral® components on the final row is done using top clips on the left and right hand sides that do not protrude beyond the final product, and screwed through the vertical joints.
The treatment of the joinery/Maestral® junctions with metal trims requires continuity of the insulation on the underside to prevent thermal bridges and it must follow the usual recommendations with regard to ventilation by means of an air gap.
Reveals are treated using the Maestral® edge profile (fitted directly to the reveal or to the cladding). Where cladding is used, supporting it requires the use of special brackets with a large overhang.
If the joinery is actually flush to the bare wall, its aesthetic connection to the Maestral® is simple. The drainage and air gap ventilation recommendations must be complied with.
The space taken up by the joinery’s peripheral sealing arrangements, particularly for the lintel, requires the provision of profiles with an overhang or special fixing brackets in the reveal.
External corners are achieved using the Maestral® corner, fitted in line with the Maestral® straight sections on the same profiles, using Maestral® corner clips.
Maestral® corners are fitted as work proceeds, attached at the bottom on two corner clips and then fixed by screwing in two corner clips at the top. The horizontal joint is usually 5 mm. Finishing external corners using metal profiles is also possible. Installing internal corners requires a simple connection between the profiles on the two adjacent grids.