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Kaupo Nõlvak
Gabor Palotas

Traditional Load-bearing Walls and Pillars

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    UNIT 1 - WOODEN, EARTH, ADOBE AND MIXED MATERIAL WALLS

    • Traditional Walls & Pillars - Wooden, Earthen & Adobe Walls

      COURSE 1 / MODULE 4 - TRADITIONAL WALLS & PILLARS / UNIT 1 - WOODEN, EARTHEN & ADOBE WALLS

    • General definitions of walls

      Walls are vertical building structures which, depending on whether they are external or internal, delimit the interior of the house or separate the different rooms. Structurally, a distinction is made between load-bearing and non-load-bearing walls and structures. Load-bearing walls bear or transfer the loads of the structures above them: walls, slabs, roofs, etc... to the structures below them, while non-load-bearing walls bear only their own weight.

      Buildings can be long-walled (long main walled), gable-walled or mixed depending on their structural system and load-bearing direction. There are different types of walls based on location and function: gable walls, main walls and partitions, basement walls and retaining walls, etc… This section looks at load-bearing walls, e.g. main walls using traditional solutions.

      1. Wooden walls          

      The first wooden wall constructions may have been palisade walls, which were later woven in a similar way to basket weaving. The most successful structures have proved to be log and timber-framed structures. These structures are characterised by using wooden joints to fit elements together.

      The walls of a log house are formed by a series of horizontal beams. At the corners, the connecting walls are built with half offsets, creating corner joints between the ends of the alternating beams above each other. For round beams, the most typical corner joints are round notch or round hewn notch joints. For rectangular cross-sections, the lapped notch or dovetail notch are the most common ones.

      For timber-framed structures, the typical elements are horizontal beams, vertical columns and diagonal bracing: such as knee braces and Andrew’s cross bracing. The most typical connections are the various types of mortise and tenon joints, the also many types of crosslap and halving joints (e.g. dovetail halving) and oblique joints.

      2. Earthen and Adobe Walls

      Earthen walls are also among the oldest man-made structures. The most commonly-used technologies in traditional construction practices were the rammed earth wall, the cob wall and the adobe block wall.
      During the construction of the rammed earth wall, the clay soil is compacted between formwork or moulding with a tamper, and raised higher and higher in layers.
      The cob wall (layered mud wall) is made from clay mud mixed with water and straw added to it. Scoopfuls of soil are stacked by hand or with a pitchfork, taking care to ensure that they are bound together. The structure is cut vertically and straight in sections using a spade.
      The adobe block is made from a mixture of mud and straw by using a mould. The dried, rectangular/ brick sized elements are bonded together using mud mortar, according to the rules of brick bonding.

      3. Composite structures

      Traditional structures were not made purely of one material. Combinations of different materials have also been highly successful, i.e. economical and useful walls were the result.

      • The mud-plastered wattle and daub wall is an ancient composite wall type. Here, the clay (daub) is applied to a woven lattice of wooden sticks.

      • The gaps between the elements of timber frame structures can be filled with materials such as wattle and daub, adobe blocks or even burnt brick.
      • The adobe wall may have been mixed with burnt brick - typically in rows, just as the burnt brick wall may have had a stone facing to the outside, or a brick lining to the stone wall.

  • UNIT 2 - TRADITIONAL BRICK AND STONE WALLS

    • Traditional Walls & Pillars - Brick & Stone Walls

      COURSE 1 / MODULE 4 - TRADITIONAL WALLS & PILLARS / UNIT 2 - BRICK & STONE WALLS

    • 1. Burnt Brick Walls

      Perhaps the most standardised form of small-element masonry that has been with us for thousands of years is the fired clay (ceramic) brick wall. The individual bricks are glued together with lime or cement mortar to form a network of horizontal and vertical joints, which also form the pattern of the brickwork. The different standard sizes were all based on the same formula: the length of a brick is twice its width plus the size of the joint. For example, a small brick measures 25 cm x 12 cm x 6.5 cm while a large brick is 29 cm x 14 cm x 6.5 cm.

      The positioning of the bricks within the wall can be either stretcher or header. The longitudinal side of the stretcher is parallel to the wall, and the longitudinal side of the header is perpendicular to the line of the wall.

      General rules for brick bonding:

      1. The size of the bricks and the height of the mortar layers must be the same in each course.
      2. The elements must always be laid with overlapping.
        The overlap should be at least ¼ brick length in the length of the wall and ½ brick length in the thickness of the wall.
      3. Avoid using quarter or smaller elements unless absolutely necessary.
      4. In alternating courses, the centre line of the brick in the bonded position must coincide with the centre line of the stretcher course above and below it.
      5. In alternating courses, the vertical joints shall form a vertical line.
      6. Stretcher courses are used only on the visible part. Inside the wall, only header bricks are allowed.

      The most typical load-bearing wall thicknesses are one-brick thick (25 cm), one-and-a-half brick thick (38 cm) and two-brick thick (51 cm).

      The one-brick thick wall can be constructed:

      • only from stretcher courses with quarter offset,
      • only from header courses with quarter offset,
      • and the alternation of the two types of courses, called the English Bond Wall.

      The most common one-and-a-half brick thick wall, and the much rarer two-brick thick wall, are built with the courses on the outside, every or every second row. Wall joints such as wall ends or wall corners are typically solved by using three-quarter elements (bats).

      2. Stone Masonry

      Stone walls also have a very long history, but they are costly to carve and thermally unfavourable. Now, they are mostly used as fence walls or as pedestals, for example.

      In their oldest form, they were laid dry without any binders. This is called the dry stone wall.
      Binder stones are typically made of lime mortar.
      Non-carved stones are known as rubble stones, and can be built in non-stratified (cyclopean) or stratified layers.

      The masonry rules are similar to those for brickwork:

      • vertical joints must not overlap;
      • each stone must rest on at least two other stones;
      • as many binding stones as possible should be installed through the thickness of the wall.

      Ashlar stones are typically built from regular rectangular carved stones of the same size, typically with the same course height and matching vertical joints in every other row.
      In addition to mortar, grooved, stone-pin, metal-pin and metal-spike joints were also used.

  • UNIT 3 - TRADITIONAL PILLARS & COLUMNS

    • Traditional Walls & Pillars - Pillars & Columns

      COURSE 1 / MODULE 4 - TRADITIONAL WALLS & PILLARS / UNIT 3 - PILLARS & COLUMNS

    • Pillars and columns are vertical load-bearing structures, which support beams and slabs as horizontal load-bearing structures at points and transfer the loads to the foundations at points. Traditional pillars and columns can be made of stone, brick or wood.

      1. Wooden columns

      In timber-framed structures, we have already talked about wooden columns which are typically connected to beams both at the top and bottom by a mortise and tenon joint. The connections are made rigid by knee braces, and the entire frame is further secured by Saint Andrew’s cross timbers.

      2. Stone pillars, columns

      When constructing the pillars (or columns) out of stone, follow the masonry rules learned for the walls. Carved stone pillars may be made from a single block, or from pre-carved pieces, called pillar drums, or assembled by grooves, pins or spikes.

      3. Masonry of brick pillars

      Brick pillars are typically made of small bricks and high-strength mortar. The simplest way to build a single brick side-width pillar is to use whole elements rotated in a course. In other cases, the masonry is built as if there were two wall ends, typically using three-quarter elements in a row or two courses.

      The brick pillar can also be reinforced using transverse (horizontal) or longitudinal (vertical) reinforcing bars. The horizontal, curved steel inserts are also placed in two perpendicular directions in overlapping layers of mortar, and this is repeated every 3-4 courses. When vertical steel inserts are used, typically 4 bars are placed along the longitudinal axis of the pillar, held together with stirrups every two courses.

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