Masonry Construction: Stone Wall Types and Techniques

Understanding Masonry Construction Techniques

Dry Stone Masonry

This type of masonry involves stacking rubble stones without using any mortar, or at most, using mud/clay. The stones are worked and carefully placed to fit closely together, ensuring that joints and gaps are minimal. These walls can be built with a slight incline or batter, typically between 1/7 and 1/5 of their height, for stability.

Mortared Masonry Walls

These walls are constructed using manufactured or natural stones laid without specific shaping, but employing mortar for bedding the stones and filling the joints. Key considerations include:

• Ensuring each rubble stone rests stably on the one below it.
• Trimming stones as needed to achieve a good fit.
• Using smaller stones, known as doggerel or riprap, to wedge larger stones securely. This process is called "enripiado".

Types of Mortared Rubble Masonry

• Coursed Rubble Masonry: Stones are laid in rough courses or layers (hiladas).
• Rubble Masonry with Riprap (Enripiado): Heavily relies on the use of small wedging stones (riprap).
• Ordinary Rubble Masonry: Uses unprepared rubble stones. Due to the lack of shaping, these walls can be prone to displacement. This is often counteracted by incorporating leveling courses of brick, known as "verdugadas" or string courses, approximately every meter, spanning two or three brick heights.

Shaped Stone Masonry

Polygonal Masonry (Concertada)

This involves walls built with stones whose faces have been roughly worked or dressed into polygonal shapes. The bedding surfaces (where stones rest on each other) are made reasonably flat, often requiring minimal dressing with a pickaxe. Stones should be wetted before placement, and a layer of mortar applied first.

Faced Rubble Masonry (Careada)

In this type, the exposed face of the rubble stones requires minor correction or shaping, typically done with a hammer or chisel. Masonry using roughly squared blocks ("Hopscotch" or mampostería de aparejo rejado) is another variation derived from block cutting.

Masonry with Inlaid Joints

This is a variation of ordinary masonry where small, flat stones or slate pieces (chinas pequeñas) are embedded into the mortar joints for decorative or functional purposes.

Small Ashlar (Sillarejo) Masonry

"Sillarejo" refers to small, imperfectly cut ashlar blocks. While generally roughly dressed, some cases involve polished faces. This type of masonry employs a specific bonding pattern (aparejo), similar to brickwork, arranging stones as stretchers (soga - laid lengthwise) or headers (tizón - laid widthwise). The combination determines the wall's thickness (e.g., a possible formula might relate wall thickness 'l' to block dimensions 'a' and joint thickness 'e', such as l = 2a + e, depending on the bond). Two main types exist:

• Irregular Small Ashlar: Vertical and horizontal joints are roughly perpendicular to each other and the wall face. They are worked (filled with mortar and finished) to a depth of at least 15cm.
• Regular Small Ashlar: Vertical and horizontal joints are carefully aligned, perpendicular to each other and to the wall facings.