Technical specification

1.1. Principle

Mortars intended for masonry of stones or blocks, made of a coarse exterior-quality gypsum plaster, with or without sand. This system is suitable for GCC area.

1.2 Field of application

Vieujot Heritage Mortars are intended for the traditional masonry of natural stones or blocks. In particular, they cannot be employed in any non-traditional systems.

1.3 Constitution of the system

Vieujot Heritage Mortars are mixes of "coarse" exterior-quality gypsum plasters, with adjuvants, with or without lime, with or without aggregate loads. They are generally counter-typed on existing old mortars.

2.1. Selection of the Vieujot Heritage Mortar to be used

The first choice relates to the proportion of plaster, lime and aggregates. According to analyses made in our facility, and to countertype an already existing coating, it is possible to vary the proportion of lime, provided that the latter remains ranging between 0 % and 40 %, in weight. In addition, one will choose the pigment and the loads necessary to obtain the color and the desired grain. This choice must be validated by the building owner or his representative.

2.2.2 Preliminary works

2.2.1 The zero state

One calls “ Zero state” the state of the support obtained after the following works:

The support must be purged of all its unhealthy or “loose” parts. In general, it must also be cleaned of any possible layer (for example paint, stains, finishing mortar, organic parts, ivy, etc ... ), by scraping or scouring. Moreover, it is advisable to observe particular precautions in the following cases:

Old coatings: purge all the surface of the current coatings and the totality of non-adherent parts in order to leave a coat thickness of at least 25 mm. Usually in fact, one pickaxes on the totality of the coat thickness until the support is reached. The remaining parts must be healthy, adherent and dust-free.

Stone and bricks of insufficient quality (crumbling, powdering, …) must be removed.

The support must take action of capillarity and raining water action

Prefabricated elements made out of hydraulic materials (stringcourses, cornices, supports, blocks, beams, …) : they must have undergone for 30 days a wet cure before being brought to be in relation to the Vieujot Heritage Mortar and that being by contact, streaming or capillarity. Once this preparation carried out, an attentive examination of the support makes it possible to check that there is not any suspect traces without explanation: traces of bistres, saltpeter (potassium nitrate) resurgence, transversal cracks, tarring, etc…

2.2.2 Preparation of the supports

Gas concrete: abundantly wet the support.

Irons / metals: proceed with a scouring and passivate. Stuffing with plaster lime. Setting out of galvanized wire-lath.

Wood: carry out an inspection and a purge: any beam presenting a deterioration will have to be uncovered on all the affected zone at least 20 cm on both sides; in the case of discovery of a cubic or fibrous rot, warn the project architect / foreman, in writing, of the possibility of a later recontamination by the mérule mushroom (serpula lacrymans; schum); removal and possible replacement; at least, brushing and fungicidal treatment. For this treatment, it is then necessary to let solvents evaporate at least for a week (more in winter) before covering it.

2.2.3 Masonry material

Stones : use clean, of enough compressive strenght stones.
Hydraulic binders based blocks (gas concrete, cement blocks, etc ...) : they must have undergone for 30 days a wet cure before being used.
2.3 Implementation of the Vieujot Heritage Mortar

2.3.1 Precautions

The code of practice for the application of a gypsum plaster masonry must imperatively be respected. The juss should not be used at a temperature lower than 5° C, neither in full sun exposure or under the rain, nor on frozen support.
The stones or blocks, whose conformity with the regulation of chapter 2.1 will have to be checked, will be humidified to saturation , without surface shine.

2.3.2 Mixing

The Vieujot Heritage Mortar implementation can be done, either: by hand, using a mixer: the mixing rate is then 50 to approximately 65% in water weight compared to the weight of the powder.
Water used will be clean and free from matter suspension. No additive or addition will be added to the product or mixing water.
In all the cases, the mix will have to be perfectly homogeneous, without clouds.
Mix should not be re tempered.

2.3.3 Masonry

The Vieujot Heritage Mortar is applied in large coat of mortar on a side of the element, then pressed in place. After setting the extra mortar is removed.

2.3.3 Drying

By taking account of local conditions (temperature, wind, air humidity, etc …) or by test application, make sure the mortar stay wet during at least 12 hours after mixing (i.e. no color changing). Water spraying and/or tarping can help.

2.4 Coating and subsequent treatments

Once finished the masonry will be plastered with Vieujot Heritage Juss or Vieujot Enduit de Montmorency

No painting, or waterproofing treatments, etc… , for lack of a specific study and of an explicit guarantee on behalf of the manufacturer and applicator, are formally prohibited.