Sumda chörten is located midway from Tsarang and Lomönthang and it dates back to the 15th century. Its name, according to the local community, means "three ways" and it marks the border and the crossroad to reach three nearby villages: Lomönthang, Tsarang and Dee. The project started with the architectural repair carried out by John Sanday Associates back in 2005. The restoration of the stuccowork and the aesthetical intervention was carried out between the summers of 2006 and 2007 by selected trainees from the Wall Painting Conservation Team working in Lomönthang.
The chörten was built using clay based plaster and stones in the lower section, and sun baked mud bricks in the upper section. The dome was protected with a wooden roof on top of which the summit was made of sun baked mud bricks and reddish sandstone bricks. All the chörten is covered with a coat of mud based plaster mixed with chopped straw.
Mud bricks, coat of plaster and stuccoworks are mixed with very fine chopped fibres of red and yellow colour. Traditionally, the chörten should have been built employing all the robes and the belongings of the lama or the high merit people buried inside the structure. All his belongings should have been chopped and mixed in all the plasters to be used for building the chörten. That explains the presence of red colored fibres found in the plaster and in the sun baked mud bricks. Furthermore, the stuccowork was carried out with a mixture of reddish clay mixed with chopped straw and the thickest high relief was secured to the surface of the chörten with small wooden sticks.
Traces of colors, found during the removal of the new plasters, proved that the chörten was indeed painted. Several thick coatings of different colors showed that the chörten had been painted countless times during the last centuries, changing every time some of the colours according, probably, to the personal taste of whoever painted it.
State of preservation: the upper section of the chörten was severely damaged by rainfall and most of the stuccowork had been washed away. The dome had lost one section on the south side and a very bad plasterwork was applied in an attempt to fix the problem. Many cracks were present all around the dome and the entrance door on the east side was detached from the main structure so that it was seriously in risk of falling down. Several layers of plaster, applied during the centuries, thickened and covered the original stuccowork in such a way that it was difficult to distinguish any pattern. The embossed Sanskrit writings below the dome were all covered by mud and a large portion had been washed away. The basement of the chörten would host two high relief mirror images on each side and only some traces were left together with a complex stuccowork in Newari style.
Consolidation work: the first operation to be carried out was the removal of all clay leakages from the ceiling together with the new plasters applied by the local carpenters during the architectural restoration in 2006. Only the original surface and the original stuccowork were preserved while everything that was added later, be it an over coating or a plaster, was completely removed. Spatulas, trowels and hard brushes were used according to the complexity of the stuccowork that had to be cleaned. This operation unveiled the original stuccowork in all his beauty.
The next step consisted in cleaning all the cracks and the lacunae in order to prepare the fractures to be consolidated. The consolidation was performed by injecting a mortar based on finely sieved local clays and a low percentage of PVA binder through syringes. The stuccowork in danger of detachment was fixed with the same solution but with a higher percentage of PVA binder. All the cracks were subsequently plastered at the same level of the surface of the chörten with a mixture of local clay, cow dung and a low percentage of PVA binder.
The entrance door frame needed a wooden propping to avoid that the pressure of the injected solution would cause the falling of that structure. A mortar made with local clays and a higher percentage of PVA binder was injected slowly and allowed to dry properly every time until the frame was completely secured back to the dome. In addition, the collapsed section of the dome was properly cleaned from all the debris and it was reconstructed using the original technique. Wooden sticks were introduced deep inside the structure every three rows of bricks to secure the new construction and to prevent the bent of the dome from collapsing.
Reconstruction work: following the requests of LomÖnthang villagers and monks it was decided to reconstruct all the stuccowork that was lost. Since there was enough stucco left, it was possible to cope with the reconstruction of the missing elements. All the remaining stucco was copied and used to recreate the lost parts. Lifesize drawings of the elements to be reconstructed were drawn and then, following the original technique of execution, short wooden bits were inserted in the areas to be plastered, so as to give strength and adhesion to the stuccowork. The surface was previously wet with a PVA binder solution to enhance adhesion between the layers. The plaster was then applied according to the thickness of the original stucco to be imitated. Then a stencil was laid over the plaster and yellow pigment was pounced to mark the shape to be cut. The excess of plaster was cut out using sharp spatulas and surgical knives so as to leave the carved stucco. During the process of drying up, the new stuccowork was wet with a solution of PVA binder and clay in water for preventing or removing any cracking from the surface.
In some cases, during the procedure of reconstructing the embossed writings, it was not possible to understand what the original writing was meant to be. In those cases, the space for the writing was left blank and unpainted.
During the consolidation work, natural pigments used to paint the chörten were found inside the dome and on the roof. Traces of colors were still visible on the surface of the building as well. Even though it was not possible to prove that they were the original colors from the construction period, especially after having found so many layers of over paintings, the monks allowed us to use them to paint the chörten. The pigments were mixed with a solution of an acrylic binder and the colours were applied by brush.
The restoration work of the chörten was completed as scheduled and the Wall Painting Conservation Team, the main lamas and the King of Lomönthang, together with the chairmen of Tsarang village attended the ceremony of consecration of the chörten, which took place on 16th August 2007.