I am an architect and I delighted to visit and study all the ancient ways of doing the trulli (trulli is the plural of trullo). I verified how all small constructive solutions are a concentration of popular wisdom.
The original cones are made without the use of any plaster and the craftsman who was committed to do this type of activity was always a specialised workman.
Nowadays there are only few specialists for doing all these details. I have funded the restoration of Trullo della Luna having clearly the aim to preserve all these aspects.
I observed how the typology of the urban trullo, the ones you can find in Alberobello, is quite different from the rural trullo, (Trullo della Luna is a rural trullo). The cones of the rural trullo are separated from each other and normally a single unit was composed by not more than 3-5 cones. All the units have a principal cone overstanding the others. In Alberobello the urban texture shows more complexity and the cones are often fused one into the other.
Some other differences are clear: a sort of basement about two feet width and about four feet tall surrounds almost all rural trulli. The characteristic of this element is its function: from its top the rainwaters, descending from the cones, drip directly into an underground tank.
Some tanks are still in use! In our Trullo della Luna I chose to take water from the artesian well.
The basements of rural trulli are often quite thick as they were built by all the small stones removed by the improved fields: All the scattered stones had to have some useful destination: the walls surrounding the crops or the basements of the trulli.
Another important characteristic of the basements is the couple of small flights of stair, normally disposed at the sides of the main entrance. Actually the external surface of the trullo was used as a good place where to leave food dry under the sun. As the stones forming the cones ("chiancarelle") were not fixed with plaster, it was really useful to have all around the cones an easy-to-reach pathway for doing the periodical maintenance.
Nowadays, considering the costs of maintenance, I have been obliged to fix the chiancarelle with a bit of plaster, but I cared to maintain the appearing surface of the cones as it was in origin.
Before buying Trullo della Luna, in order to choose the best one, I patrolled all the territory and realised there are even local differences. I can distinguish four main types as shown in the pictures below. Of course different aggregations are possible but they easily may derive from the basic ones. Our Trullo belongs to type n.2, with a main cone and three secondary cones. To update the building to current demands we added a bathroom and a bedroom conforming the typology to n.3. The new added portion is not cone-covered as we refused to build a not original and philologically wrong one! The difference would be too much relevant: we do prefer the adoption of the "lamia" typology with tufa vaults and squared walls.

The owner: Paolo Devescovi

Other info about the trulli:

Archirent News - Where did the peasants take the construction materials for the trullo?
Archirent News - Who did build the domes of the trulli and how?

In Alberobello facades are continuous without a basement and cones fuses each others
The rural trullo has a less complex
geometry and a basement with stairs all around.
Trullo della Luna before the restoration works