The architecture of each region is a response to various external conditions such as climate and geographical zoning. The diverse climatic ensemble of Gilan has embedded within itself certain dictates for the construction of various buildings, obligating the Gilani architect to follow the unwritten directives of architecture. Due to the absence of distinct boundaries between the climatic zones of this region, it is not possible to strictly separate types of architecture into specific geographical domains; indeed, in some areas that lie at the border between two climatic zones, various types of architecture — both in materials and construction methods — have sometimes been employed in hybrid fashion. In this article, the author has endeavored to examine those components of building construction most prevalent across the different zones of the region.

Foundations and Substructure. Shekili Foundation: In low-lying and plains areas, the Gilani architect used a raised substructure to prevent rising moisture from penetrating the building floor. However, depending on the elevation of the area relative to sea level and the type of locally available materials, different methods of substructure construction

were employed. In some areas, to allow airflow beneath the building and thereby cool the floor during hot seasons, a type of porous substructure called shekili was used. In this method, the ground is first leveled, the substructure is erected from stone and kneaded clay, and its surface is coated with straw-mud plaster. This substructure is built with various pieces of timber of different dimensions (known locally as rit, zi, katel, and fak) to prevent moisture from reaching the upper section. Two beams (boneh-dar) are placed atop these rows, and then thick joists (sarkesh) that form the floor of the house are laid upon the beams (Figure 1). Pakuneh Foundation: To build this type of foundation (specific to areas with lower soil moisture), timbers called pakuneh are first designated for the skeleton of the foundation, and a portion is placed in a pit whose bottom layer has been dry-laid with stone. This is then secured with a mixture of kulush-gel (straw-clay) and sometimes a combination of sand and lime, while the remaining length of the timber, called the kursi, is left above ground. After this stage, four thick beams (known locally as jirnal) — functioning as base plates beneath the columns and for the purpose of tying the structure together — are mounted atop the pakuneh timbers. These beams form the building's supports (Figure 2). Stone Foundation: With increasing altitude, the thinning of forests and the consequent reduction of harvestable tree species gradually led to decreased use of timber in buildings, and other local materials such as stone became more prevalent. In this type of foundation, the architect creates a uniform bed of stone, and after leveling its surface, prepares the conditions for the lower tie beams of the building to rest upon this stone bed (Figure 3). Tall Substructure: Another common method of substructure construction in the region, prevalent in many urban buildings, involves constructing the substructure like a platform using a combination of cobblestone, ash, and lime mortar, or a combination of brick and clay, beneath the building. Due to the density of materials in this substructure, ventilation beneath the building is impossible (Figure 4).

Walls. In the lowland plains of Gilan, owing to the saturated humidity in the air, there is no pressing need for prolonged heat retention within the building. Consequently, in wall construction, timber is the architect's first choice; for in addition to easy accessibility, it allows for thinner walls and thus greater efficiency against desirable wind flow during the hot months of the year (compared to masonry materials). Some of the common methods of wall construction are as follows: Zagameh Wall: This type of wall is prevalent in areas with richer vegetation. For wall construction, round logs are generally used. To position the timbers and prevent them from sliding, a notch is carved from both ends of each beam, causing each beam to interlock with the one before and after it. After stacking the timbers upon one another, the gaps between them are filled with clay, and for the finish coat, the surface is plastered with straw-mud (Figure 5).

Zegali Wall: In this type of wall, tree branch wood (known locally as zegal) and clay are generally used as filler. First, wooden columns (squared timbers) are erected, and the zegals are attached to them diagonally up to the desired wall height; kneaded clay mortar is then poured between the two rows of inner and outer zegals. Subsequently, the interior and exterior wall surfaces are plastered with a thinner mortar containing more straw (Figure 6). Chineh Wall: In the foothills of Gilan, with its forested and relatively cold climate, maximum utilization of sunlight and protection from cold winter winds are among the most important climate-related factors in the formation of architecture. The materials of choice for these walls are timber, clay, and stone, with varying priorities. The construction method for the chineh (layered) wall is as follows: first a layer of straw-mud, then a layer of river stone (or handmade mud brick), then straw-mud mortar again, and finally a piece of oak wood (mazu) to level the surface. These four layers are repeated to the top (Figure 7). Stone Wall: In the mountainous regions of Gilan, due to the cold climate — especially in cold seasons — and the abundance of hard materials such as various types of stone, walls are built solely with this material along with clay mortar (Figure 8). Brick Wall: Despite its considerable resistance to moisture-induced decay, this material has low air permeability and is more difficult to access compared to timber, which has caused it to be less popular among the local population; it is generally used in the homes of wealthier individuals (Figure 9).

Porch (Ivan). Given the proximity of Gilan's lowland areas to the Caspian Sea, air humidity in these zones is very high. The porch is a semi-covered space that, by creating shade, aids in temperature moderation

Figure 6: Zegali wall in Laton village

Figure 7: Details of chineh wall in Vaskeh village. Figure 4: Building with tall substructure in Amlash county

within the building and plays a significant role in controlling the building's thermal behavior. As breezes blow against the outer walls, this coolness penetrates into the rooms, and the saturated humidity in the air also helps temper the interior spaces. With minimal enclosure and maximum ventilation and cross-breeze, the porch accommodates most of the household's domestic activities during hot weather and serves as an intermediary between the warm indoor air and the cold outdoor air in winter, and as a filter separating wet and dry spaces during rainy days (Figure 10) (Khakpour, 2013, 82).

Roof. Given the abundance of rainfall and the frequency of rainy days, a sloped roof is an appropriate solution for preserving the building. The roof slope varies in different areas and depends on the roofing material; the smoother the material, the gentler the slope. "The final roof covering material in Gilan (before the introduction of corrugated metal sheets) was generally thatch or tile, and naturally, thatched roofs were more vulnerable due to their use of plant-based covering and required steeper slopes to combat rotting from rain. The substructure of all types of thatched, tiled, and lat-covered roofs is made of timber" (ibid., 85). The types of these coverings are as follows: Thatched Roof (Gali-push): To construct the roof, four long wooden beams — which essentially form the main skeleton of the roof — are first bound together on the ground in a triangular shape, then transferred onto the building. All vertical and horizontal beams are connected to each other using plant fibers (known locally as viris) to form a network of the main roof skeleton. Then bundles of kulush or gali are also bound together with viris and placed between the horizontal laths (Figure 11). Tile Roof (Safal-push): This type of final covering consists of tile pieces laid upon the roof skeleton. To build the skeleton, lathing is carried out along the length of the sloping beams. In calculating the lathing, attention to the end laths and the ridge line — whose spacing from both slope directions remains constant — is of great importance. Tiles of various shapes are used in interlocking courses along the slopes (Figure 12). Lat-Covered Roof (Lat-push): In areas of higher elevation and sloped terrain, the Gilani architect makes the ingenious choice of using wood from trees such as beech and oak (mazu) for roof covering, taking advantage of their superior splitting quality. To prepare these thin sheets called lat (lateh), the tree logs are cut and used to cover the entire roof surface. The roof skeleton is also wooden, and the lats are laid from the eaves upward toward the ridge. After placing the lats in the first row, the lats of the second row are placed over the gaps between the lats of the first row, and this arrangement continues to the top of the roof. The steep slope ensures that rainwater flows easily from the upper lat to the lower lat and then to the ground, without finding the opportunity to penetrate inside. In the past, nails were never used at any joint of the lats, and stones were placed at the ridge line and the windward side to prevent the lats from shifting (Figure 13). Pushte-Dadan (Stepping the Roof): One method of widening the porch roof is by stepping it. In this technique, the interior face of the roof is tiered, with each tier projecting farther than the previous one. This technique of extending the wooden beam increases the length of the porch roof overhang, which itself prevents angled seasonal rain from reaching the walls. Naturally, with more steps, the area of the roof overhang increases (Figure 14).

Materials. In the lowland villages of Gilan, the extremely high rainfall provides abundant opportunities for harvesting timber and other plant-based materials from nature, and the ease of access to various natural materials has led to their widespread use in building construction — to the extent that in the central plain, all layers of the building from structure to ornamentation and from foundation to roof are composed of these materials. Given the considerable relative humidity in this region,

Figure 9: View of a manor house in Ti-Tek village. Figure 8: Details of stone wall at Samamoos shrine

Figure 11: Residential house with thatched roof at the Rural Heritage Museum, from the Gilan plain. Figure 10: Porch in Foosheh village

the temperature differential between day and night, sun and shade, as well as between summer and winter, is very slight; therefore, the use of timber as a material with low thermal capacity is justifiable. For constructing lighter components that require less load-bearing capacity and are simpler to join (such as roof frameworks and interior ceiling coverings), lighter species like poplar and alder are used. The Gilan plain is the product of river deposits, and materials such as alluvial and clay soils are readily available in the region and are used as fillers and mortars. In elevated areas where the groundwater table is low, combating rising moisture is not the primary concern of the builder. In these locations, as one moves from lowland to highland areas, due to the thinning of forests and decreased timber resources, stone is used as a substitute material.

Ornamentation. Due to the predominant use of timber in the majority of Gilan's buildings, ornamentation is generally carried out on this type of material. The varieties of ornamentation include woodwork on railings, columns including column capitals and column shafts, chekesh-gardan (rotating hammer beams) in the stepped porch roofs, as well as various types of halab-bori (sheet-metal cutwork) in roofs covered with galvanized sheet metal. Wall ornamentation generally consists of floral motifs. These relief patterns are usually fashioned from kneaded local clay, affixed to the wall, and then coated with white lime plaster. Due to the extroverted character of Gilan's architecture — especially in the plains zone — all ornamentation is visible on the building's exterior facade, particularly the transparent layers of the porch and the outward-facing walls of rooms. Typically, before Nowruz each year, the exterior facade of the house is whitewashed with limewash and a broom. This finishing treatment is pursued with less rigor on interior facades (Figures 15 to 17).

Conclusion. The climatic diversity of Gilan forms the foundation for diversity in the body of the region's vernacular architecture; indeed, this variety is observed in all building components — foundation and substructure, walls, roof, materials, and ornamentation. The height of the building from the ground level depends on the groundwater table; as one moves from lowland to highland areas, the decreasing rising moisture results in reduced porosity of the building's foundation and increased contact area with the ground. The climate-driven approach of Gilan's architecture has caused the use of timber to extend to all layers of the building, including walls and roofs. This degree of timber use is greater in plains areas due to the presence of forested zones and diverse wood species. With increasing altitude and the abundance of rocky terrain in nature, timber use decreases and stone materials find greater application in buildings. Consequently, in the lowland and plains zones of Gilan, timber and clay have the greatest usage; in the foothill zones, timber, clay, and stone are used in that order; and in the mountainous zones, stone and clay gain predominance.

* Minoo Khakpour: Assistant Professor at the University of Science and Culture (Rasht campus) — PhD in Art Research

Footnotes: 1. Kulush: rice stalk fibers. 2. Viris: rope woven from rice stalks, used in various joining operations, including the application of thatch covering. 3. Gali: a plant cultivated in Gilan specifically for the final roof covering, considerably more durable and uniform than kulush. 4. Although timber, compared to clay, lacks the capacity for curved shaping, and ornamentation (unlike other parts of Iran) is not intricate or diverse. 5. Chekesh-gardan: wooden beams in multi-stepped roofs that, through their sequential placement, extend the main beams.

References: Khakpour, Minoo (2013), "Typology of Sacred Shrines of Lahijan," Scientific Research Quarterly of Iranian-Islamic City Studies, No. 13, pp. 81–92.

Figure 12: Residential fabric with tiled roofs in Lahijan

Figure 15: Taromi and wooden ornamentation beneath the porch in Mooshanegah village

Figure 16: Halab-bori in Sharabandi village. Sketch: Common types of porches in Gilan's plains areas

Figure 13: Residential building with lat-covered roof in Buyeh village. Figure 14: Four-stepped roof in Shekarpos village

Figure 17: Ornamentation on column shafts and capitals in Amir-Hendeh village

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