Fiorditufo blocks for load-bearing walls, facing brick or cladding, should always be clean and without dust, and watered thoroughly a few hours before installation to be, however, almost dry at the time of use.
For the wall construction is appropriate to use a good lime mortar, or a cement mortar with hydraulic lime, in layers sufficiently thin, that maintain qualities of workability and plasticity for a time period enough long.
The surfaces of the blocks, filled with vacuoles, offer very high adhesions, if clean and moist and if the mortar is sufficiently thin to penetrate and fit the irregularities of the blocks surfaces.
Only in this way, the mortar, placed in work in a fluid state, adapts to the surfaces and, with the normal progress of the construction, the weight of the masonry and other structures that will release on it during the long phase of the mortar setting, will be enhanced those chemical and physical processes that produce the adhesion forces between blocks and mortar which are the essential component of the wall resistance.
During the floors casting, their weight, that release on the wall, and the plasticity of the mortar setting beds of the wall loaded, achieve a mutual adjustment of the two structures – floor and wall, depending on the time required for the mortar setting, may continue even after the removal of any floor props and the subsequent laying of permanent overloads.
The adjustment between the floor panel and the upright wall, being realized through the beds of mortar, involves a slight rotation of the upright building that lays so that to receive the support of the floor with a substantially uniform distribution of the contact pressures.
This phenomenon proceeds and become more marked until endure the plasticity of the mortar, both with the imposition of the subsequent loads on the floor, and with the weight of walls and floors of over orders transmitted to the building level considered with the progress of construction.
Differently from what happens in the masonry in which the horizontal mortar beds are less resistant and with an elastic field a much more extensive than blocks, in which the mortar is plasticised absorbing the horizontal traction forces, which cause the breakage, in the masonries of Fiorditufo blocks the similar resistance of the two materials leads to stresses substantially uniform and uniaxial.
The rule of law indicates thicknesses of mortar between 5 and 15 mm, for both horizontal and vertical joints, which must be completely clogged, especially for exterior walls, in order to ensure the necessary watertightness, even under the action of the rain.
For facing brick wall must perform an energetic upsetting of mortar on joints at least every five courses, smoothing if a flush joint and giving other forms if you want bucket handle or recessed joint.
In places particularly exposed, where it can be necessary a high resistance to driving rain and wind, it is advisable to leave the joints open for 2 or 3 cm inside the masonry and, facade completed, proceed to a prior thorough brushing and then grouting with cement mortar richly dosed and made with silica sand of quarry basalt.
During breaks of the work, the walls built must be carefully covered to protect them from rain, sun’s heat, the dryness of the climate and too low temperatures.