Stonemason

Creating buildings, structures, and sculpture using stone from the earth. These materials have been used to construct many of the long-lasting, ancient monuments, artifacts, cathedrals, and cities in a wide variety of cultures.
Igneous stones
Granite is one of the hardest stones, and requires such different techniques to sedimentary stones that it is virtually a separate trade. With great persistence, simple mouldings can and have been carved into granite.
Generally, however, it is used for purposes that require its strength and durability, such as kerbstones, countertops, flooring, and breakwaters.
Igneous stone ranges from very soft rocks such as pumice and scoria to somewhat harder rocks such as tuff and hard rocks such as obsidian, granite and basalt.

Metamorphic
Marble has traditionally been used for carving statues, and for facing many Byzantine and Renaissance Italian buildings. The traditional home of the marble industry is the area around Carrara in Italy, from where a bright white marble is extracted in vast quantities.
Slate is a popular choice of stone for memorials and inscriptions, as its fine grain and hardness means it leaves details very sharp. Meanwhile, its tendency to split into thin plates has made it a popular roofing.

Sedimentary
Many of the world's most famous buildings have been built of sedimentary stone. There are two main types of sedimentary stone used in masonry work, limestones and sandstones. Examples of limestones include Bath and Portland stone.

Repointing

With exposure to wind, rain, frost etc, the mortar holding bricks (or stone) together on an external wall will often start to crumble away and fall out.

On older properties, the pointing will actually be a harder mortar than the bonding mortar, so once this is dislodged, the softer bonding mortar will become exposed and wear away quite quickly.

This repointing process begins by removing damaged pointing to a depth equal to or slightly more than the with of the joint, or to the point where sound mortar is reached.

On very old buildings with soft materials, such as under-fired brick, removal by hand is often the most effective to avoid damage.

Hard Portland cement mortar is usually removed with a grinder or power circular masonry blade, taking care not to damage the masonry units. Vertical joints in most cases are always done by hand or with small power chisels.

Poor repointing work often raises the level of the mortar joint above the face of the masonry unit, which causes the mortar edge to feather.

Repointing materials

It is essential that the mortar used for repointing have similar performance characteristics to the original mortar used in a building.

Mortar used for re-pointing should normally be based on hydraulic lime and clean sharp sand or other appropriate aggregates. The colour and size of the sand particles determine the appearance of the mortar.

The existing older mortar should be carefully examined so that aggregates used in re-pointing can be selected to match existing mortar for texture and colour.

The strength of the mortar should reflect the strength of the stone or brickwork and the exposure to weathering.

Sandstone requires a weak mix while whinstone will allow a firmer mortar bed but not so hard as to cause cracking and capillary pathways for water. Exposed chimneys will need a more durable mortar than a sheltered area of walling.

Lime is a general term for calcium-containing inorganicmaterials, in which carbonates,oxides and hydrohides predominate.

Materials are still used in large quantities as building and engineering materials (including limestone products, concentrete and mortar) and as chemical feedstocks, among other uses.

The rocks and minerals from which these materials are derived, typically limestone or chalk, are composed primarily of calcium carbonate. They may be cut, crushed or pulverized and chemically altered.