In order to understand the performance of the housing typologies being considered here it is important to understand their materiality. The following factors will be presented and discussed in relation to the building construction for each house type (see Table 2.2).
Table 2.2. Building construction of the traditional and modern house
Foundations Traditional Modern
x
x
Walls Retaining
x
N/A Externalx
x
Party
x
x
Internal
x
x
Roofs Parapet walls
x
x
2.2.1.1. Building materials of traditional houses
Foundations: In terms of their construction traditional houses are typically built on a foundation of step down strip foundations built of hard-burnt brick and the mortar used is either lime (Noora) and ash (Ramad) or lime and sand. The thickness of the
25 foundation depends on the wall above and the depth they have to go down to; therefore they vary around 700–1200 mm (Al-Azzawi 1984).
Retaining Walls: The retaining walls are among the most important walls of the traditional courtyard house. They can be identified here as the walls found at the basement level room (Sirdab) and semi-basement level room (Neem) and also these walls could be part of the external walls, party walls, the walls overlooking the courtyard and also even the internal walls.
The retaining wall which is part of the external wall and the party wall is always thick, typically 700–900 mm and consists of two skins of brickwork with broken bricks between these two skins. The external skin consists of multi-brick or Brak brick and the internal skin consists of different types of broken bricks (Al-Azzawi 1984).
While the retaining wall which is part of the wall overlooking the courtyard is not as thick, 450–700 mm, it also consists of two skins of brickwork with broken brick between. The external and internal skin of this wall consists of Brak brick.
The retaining wall which is part of the internal wall consists of the same construction and same materials as the retaining wall which is part of the wall overlooking the courtyard and the thickness of this wall is about 450 mm.
It can be seen that these walls provide significant thermal mass to the buildings and as such may influence the internal thermal environment significantly, in particular lowering the internal temperature peaks during the summer.
External Walls: The external walls of the traditional courtyard house are very thick;
they are 500–700 mm thickness and consist of skins of brickwork. These walls are built of heavy-weight construction.
Parapet walls overlooking the alleyway are built of light-weight construction consisting of full-height corrugated iron sheets (cheenkoo) fixed to vertical wooden studs (4 in diameter) at about 3.0 centres and horizontal wooden battens (a sole plate, a top batten and an intermediate batten) (Al-Azzawi 1984, p. 131).
The parapet wall overlooking the alleyway is constructed as a timber balustrade about 1000 mm high consisting of top rail and bottom rail with vertical cast iron bars between them and wooden balusters at 1500–2000 mm intervals.
Sometimes, a full-height privacy screen of timber lattice-work is fixed to the
26 balustrade to prevent overlooking between neighbours across the alleyway (Warren and Fethi 1982).
Party Walls: Party walls at ground floor level are very thick; they are 500–700 mm thickness, built of skins of brickwork and the insulation is broken bricks. These walls are built of heavy-weight construction.
At first floor level the party walls still are very thick, but they are 400–500 mm thickness. They are also built of skins of brickwork and the insulation is broken bricks.
The party walls of the roof terrace are built of brickwork and sometimes are built of light-weight construction. The party walls of the roof terrace incorporate natural ventilation (Badgir) inlets.
Internal Walls: The internal walls of the basement level room (Sirdab) and semi-basement level room (Neem) are very thick, 500–700 mm in thickness of the brickwork. The construction materials used for the internal walls are similar to the materials of the retaining walls. The internal walls between the habitable rooms are about 500 mm in thickness; they are built of brickwork (Al-Azzawi 1984).
Roofs: The roof of the traditional house is always flat in the form of a terrace and it is located along two, three or four sides of the upper part of the courtyard. In the case of small or medium traditional houses, the roof terrace is finished with two layers of a mixture of clay and chopped straw. This mixture of red earth and chopped straw is mixed with water and left for at least two days. This material provides some insulation to the penetration of heat from the day into the internal spaces as a result of air trapped in this construction material. In the case of large traditional houses the roof terrace is finished with paving bricks (Warren 1984).
Parapet Walls: The roof terrace of the traditional house has parapet walls and they are always built in two thicknesses:
• The lower part is typically around 900 mm high and this part is very thick with about 250 mm brick or 225 mm brick with Gypsum (jus) as a mortar (Warren
& Fethi 1982).
• The upper part is about 900 mm above the roof terrace and up to 19 mm high and this part is very thin and built of bricks (8 x 8 x 2) and again with Gypsum (jus) as a mortar (Warren & Fethi 1982).
27 2.2.1.2. Building materials of modern houses
Foundations: The foundation of the modern house consists of a strip of concrete footing about 450–675 mm wide and about 300 mm thick, at about 600–750 mm below natural ground floor (Al-Azzawi 1984). This concrete incorporates brick of 350–450 mm thickness and the rest consists of sand and cement.
External Walls: These walls are relatively thin when compared to those of the traditional courtyard house, with typical thicknesses of 220–320 mm of brickwork.
The external walls are usually rendered on the outside and plastered on the inside and as a result this increases the thickness of the wall slightly to a maximum of 350 mm in total. These walls do not provide the same protection from the very hot summer climate as their thermal mass is substantially lower than that provided by the construction of the traditional courtyard houses. It should be noted that for the larger sized houses the external walls, especially those overlooking the road, consist of two skins, the internal skin about 230 mm and the external skin about 120 mm of brickwork. The external walls at first floor level consist of 230 mm of brickwork and it has the same materials as the external walls at ground floor level. They are rendered from outside and plastered from inside (Al-Azzawi 1984).
Party Walls: The party walls of the modern houses are similar to the external walls and have the same building materials. The party walls are not thick in comparison with the party walls of the traditional houses; they are 230–340 mm of brickwork (Al-Azzawi 1984).
Internal Walls: The internal walls of the modern houses are relatively thin, 200–225 mm in thickness, and are built of brickwork. At first floor level the internal walls are of a similar construction.
Roofs: As is the case for the traditional courtyard houses, the roof terrace of the modern house is always flat. The roof is typically built of brickwork bedded in Gypsum (jus) mortar. This type of construction is called ‘Igada’, where the lower part of ‘Igada’ is plastered over while the Gypsum (jus) and water is applied to the upper part of ‘Igada’ to give a water-proof layer. The roof terrace is then finished with terrazzo tiles (kashi) about 24 mm thick bedded in Gypsum (jus) mortar (Warren 1984).
28 Parapet Walls: The roof terrace of the modern house has parapet walls which are not high enough for privacy, about 1200 mm in total and have been built in one thickness of about 150 mm or 180 mm bricks or concrete, using Gypsum (jus) as a mortar (Warren 1984).
2.2.1.3. Comparison of building materials of traditional and modern houses
Table 2.3 below provides a comparison of building materials used in traditional houses built at the end of the eighteenth century/beginning of the nineteenth century and modern houses built at the end of the twentieth century in Baghdad.
Table 2.3. Building materials of traditional and modern houses
Foundations:
Traditional Modern
Materials/ Thickness
Hard-burnt bricks Strip of concrete footing 700–1200 mm thickness 350–450 mm thickness Walls: Thickness
Retaining: 700–900 mm thickness N/A
External: 500–700 mm thickness 220–320 mm thickness
Party: 500–700 mm thickness 230–340 mm thickness
Internal: Sirdab/Neem 500–700 mm thickness 220–225 mm thickness Roofs: Thickness
Parapet walls: 250–225 mm thickness 150–180 mm thickness