Custom Decorative Plasters

Technical specification

P.O. Box 450163
Dubai, UAE
Tel : +971 50 281 48 44
Fond de Stuc

Fond de Stuc
Thin internal plasters with gypsum plaster and lime. Specifications n° EM10.0


1.1. Principle
Fond de Stuc is intended to realize a thin plaster 1/10 inch to 1/4 inch (2 to 6 mm) for the finish of the internal surfaces in wall or ceiling.
Fond de Stuc is a mixture of gypsum plaster and lime, with or without loads, (silica, limestone, silicates, etc.), possibly tinted in the mass.

1.2. Field of application
Fond de Stuc is intended for the finish of flat, homogeneous, stable and dry internal surfaces in wall or in ceiling.

1.3. Constitution du système
Fond de Stuc is a mixture of gypsum plaster and lime, with adjuvants, with or without aggregate loads, tinted in the mass or not.
It is always delivered ready for use: no addition (adjuvants, load, etc.) can be added on construction site except the compatible mineral pigments with the gypsum plaster and the lime within the limits of 5 % of the weight. A preliminary try is then essential.


2.1. Choice of the Fond de Stuc
A sampling will be realized to validate the composition, the texture, the finish and the colour.
This choice must be validated by the contracting authority or his representative.

2.2. Preliminary works

2.2.1 The initial state
The support has to be:
* Stable : Fond de Stuc constitutes on no account a reinforcement of the support. This one must thus be stable, in particular in term of dimension and curvature, by taking into account the pure weight of the Fond de Stuc including during the implementation when this one is still wet (specific weight: 2 kg / m²/mm in thickness). He does not either have to deform under the effect of the finish (smoothing and sanding for example). Of course, the support must not be cracked.
* Flat : the variations of thickness of the future stucco will have to be lower in the middle of the average thickness. The support must be purged of all its unhealthy or not united parts.
* Homogeneous: in term of absorption. Possibly, we use a thorough regulator or an impression to this end.
* Dry: he does not have to have effect of water, neither on the support, nor by the streaming, splashing or by condensation.
* Clean: in a general way, the support must be cleaned by any element not properly attached to it (for example scaled paint, spots, dust, fat body, liquid of form removal, traces of bistres, saltpeter (i.e. potassium nitrate) resurgence, etc..).

Furthermore, it is advisable to take particular precautions in the following cases:
* Supports packaging a hydraulic binder - cement, hydraulic lime, etc. - such as concrete, cement plaster or scratch coat, cement boards, prefabricated elements, concrete blocks: they must have undergone a wet cure of 30 days before being coated.
* Closed supports (plasterboard, wooden panels, concrete, paint, etc.): they must have received a primer.
* Coated supports (scratch coat, coated cements plaster, coated gypsum plaster, etc.): they have to present a sufficient roughness. Failing that, they must be printed.
* Joints: the functional joints of the support do not have to be covered. The support will be in accordance with its rules of application, in particular as regards the treatment of openings, the breaks between floors or maximum surfaces.

2.2.2 Preparation of the supports
We remind that Fond de Stuc is a purely ornamental plaster: he can play thus no role in the stability of the wall or the building, or in his joinery. This stability and this joinery must be insured before the implementation of the plaster. In particular, any fissuring connected to movements of the support, connected or not to works, predictable or not, is not covered by the warantee.

2.3 Thorough implementation of Fond de Stuc

2.3.1 Precautions
The rules of the art of implementation of a filler plaster owe necessarily respected.
The plaster must not be used in a temperature lower than 5 ° C, either right in the sun or in the rain, or by strong hot season, or on ice-cold support. The building has to be outside water.
The support will be verified; in particular in its conformity with the prescriptions of the chapter 2.1 in the case of a porous support moistened in refusal.

2.3.2 Mixing
The thorough implementation of Fond de Stuc can be done, either by hand, using a mixer or by spraying, with a suitable machine: the rate of mixing is then from 40 to 55 % around weight of the water with regard to the weight of the powder, following loads.
In every case, the rate of mixing has to allow obtaining a dough holding charge some 1 to 1 ½ inch (3 to 4 cm) thickness.
The water used will be clean and exempt from suspension materials.
No additive or addition, other than pigments adapted to the plaster and to the lime, will be added to the product or to the water of mixing.
In every case, the mixing will have to be perfectly homogeneous, without clods.
You should not retouch the coating when the hardening has begun.

2.3.3 Coating
The plaster is applied in only one sole homogeneous layer of the desired thickness. In no case should the thickness should be lower than 1/10 inch (2 mm), once the coating finished. The maximum average thickness will be ¼ inch(6 mm).
The maximal variation in the thickness of the coat will be lower than half of it's average thickness.
Fond de Stuc is floated with a strike, then even up with a smaller blade.

2.3.4 Finishing
After setting, we can finish the Fond de Stuc by:
* Cutting with a sharp berthelet
* Scratching with a nail float
* Brushing with a flexible brush
* Wash after setting (sponge float, brushes hard manual worker either on polish machine or jet with pressure adapted). If necessary, it will then be rinsed in a careful way with water slightly under pressure, so as to eliminate laitance.
* Cleaning with the wire brush. The hardness of the metal will be adapted at the stage of setting.
* Smoothing with or without the use of the sponge float.

Fresh coating must be protected from direct sun exposure. Moreover, it must remain wet at least a week. If necessary, it is appropriate of re-humidify the coating with clean water and a spray.
Conversely, it is advisable to prevent the coating from remaining wet for too long, whatever the cause is, so that carbonation may be accomplished.

When hardness permits, the coating can be re-cut, in particular for joint scoring.
Once perfectly dry, the coating can also be sanded or renovated, (including rubbed finishes such as sand-spraying) like a very tender stone.

Of course, the minimal thickness constraint of 1/10 inch (2 mm) has to be respected, included these works (in the case of dug joint left unfilled, the thickness is measured from the bottom of the joint; in the case of dug joint filled in white or tinted coating of Fond de Stuc, the thickness is measured from the surface of the coating).

2.4 Particular points of implementation

2.4.1 Protection against the water
In a general way, surfaces realized in Fond de Stuc must be protected against the water, in particular the capillary raises, the localized streaming and the splashing.
2.4.2 Junction with the ground
Fond de Stuc can be implemented up to the ground. It is however recommended to plan a skirting.
2.4.3 Junction with the other elements
We shall respect a hollow joint being enough for the circumference of the various elements adjoining the support (beams, built, centre) with possibly the use of a joint - silicone or besides - adapted.
2.4.4 Precautions in the course of construction site
All the necessary precautions will be taken to avoid the damages bound to the temporary conditions of construction site (we shall watch in this respect a good phasing of construction site), etc.

2.5 Subsequent treatments
Any later treatment - whether it is in covering or in contact - other than those purely physical (sanding, joint scoring, re-cut) on the background of finished Fond de Stuc owes compatible with the nature of the Fond de Stuc, consisted of plaster and lime.
The filler can be waxed and polished. The conditions and the limits of use are the ones restraints for fillers on base plaster by manual application (cf. documents corresponding to the used type of finish: Technical Standard NF standard DTU 59-1 ranking P 74-201).
Fond de Stuc is not intended to receive a ceramic cover.

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