Material Reality in Asunción's Perimeter
If you walk through Villa Morra's edge or the barrios around Fernando de la Mora, you will see the same three materials repeated across thousands of structures. The informal housing built there follows a logic that has nothing to do with aesthetics and everything to do with availability, cost, and what the local scrap economy offers. Brick exists but is expensive. Cardboard is free but falls apart in rain. Corrugated iron solves both problems until it becomes a problem itself. That is the basic tradeoff. The walls start with whatever is lying around. Cardboard comes from grocery stores, electronics shipments, and warehouse districts near the Mercado 4 area. It gets layered over wooden frames made from pallet scrap or discarded furniture. The result holds for roughly two rainy seasons before it delaminates and needs replacement. Most families rotate through this cycle without formal maintenance because the material costs almost nothing to source. Corrugated iron sheets dominate roofing and exterior wall cladding. You will find them in varying conditions. Some are brand new, purchased from local ferreterías for around Gs. 120,000 to Gs. 180,000 per square meter installed. Others are salvaged from construction sites or demolished buildings, often dented, rusted, or missing their original galvanized coating. The salvaged sheets cost nothing beyond transport, which usually means a pickup truck ride arranged through a neighbor.
Brick appears in the more established sections where families have moved from pure informal construction toward semi-permanent structures. A single hollow brick, known locally as bloque, runs about Gs. 8,000 to Gs. 12,000 depending on the supplier and distance from the manufacturing plant. Cement adds another layer of expense. This is why brick construction tends to happen room by room over several years rather than all at once. The floor situation is almost always concrete that was poured unevenly or left unfinished. Many homes never get a proper floor treatment. They have compacted earth or cracked cement slabs that collect standing water during heavy afternoon rains. I worked on a housing assessment project near Mariano Roque Alonso in 2019 where we documented thirty units and only four had any kind of finished flooring beyond basic concrete. The rest had dirt floors that turned to mud seasonally.
How These Materials Interact In Practice
The combination of cardboard and corrugated iron creates a specific set of problems that people who have never lived in these conditions tend to overlook. Cardboard absorbs moisture rapidly. When it gets wet, it loses structural integrity within hours. In a place like Luque or Itauguá where the dry season gives way to sudden afternoon storms, a cardboard wall can collapse during the night if the family is not alert. Corrugated iron exacerbates this problem. Rain hitting metal sheets produces noise that makes it difficult to sleep, which sounds trivial but affects everything. More importantly, the thermal dynamics are brutal. Interior temperatures inside a corrugated iron structure can reach 45°C or higher during Paraguayan summers, even in shaded areas. The metal conducts heat directly into the living space. Families often hang wetcloths or additional layers of cardboard on the interior to create some thermal buffer, which then becomes a mold risk. I encountered a specific issue while working with a micro-housing initiative near the Río Paraguay banks. The community had been using tarps and patched corrugated iron for roofs, but condensation buildup was creating mold on the interior walls faster than anyone could address it. The workaround was straightforward but required materials that many families cannot easily access: we installed a vapor barrier layer using repurposed plastic sheeting between the interior wall surface and the existing structure, then added ventilation gaps at the eave line using salvaged wood strips. This reduced interior humidity by roughly 30 percent during the rainy season. It did not solve the root problem of inadequate roofing, but it stopped the immediate health risk.
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The Structural Hierarchy
There is an unspoken material hierarchy in these settlements. At the bottom you have purely temporary structures made from cardboard, plastic sheeting, and whatever framing is available. These structures typically last six months to two years. Moving up one level, you find cardboard walls reinforced with corrugated iron sheathing, which extends the lifespan to roughly three to five years. The next tier involves partial brick construction, where the family has accumulated enough resources to build one or two rooms with proper masonry while keeping the rest of the structure in lower-grade materials. Full brick construction with tile roofing represents the top of this hierarchy and usually indicates a family that has been in the same location for a decade or more. This progression is not linear. Many families move backward rather than forward. A flood can destroy a brick foundation. A rusted roof sheet can collapse during a storm. I have seen multiple instances where a family invested two years of savings into a proper block wall structure, only to lose it when the metal roof was torn off by wind and they could not afford to replace it, forcing them back to cardboard and scavenged materials.
Supply Chains And Sourcing
The material economy that feeds these settlements operates on informal networks. Cardboard arrives through the same distribution channels that supply commercial businesses. People who collect and resell recyclables, known as cartoneros, are the primary source. They strip cardboard from packaging shipments and sell it in bundles or individual sheets depending on the buyer's budget. A bundle of flat cardboard might cost between Gs. 15,000 and Gs. 30,000, which translates to roughly twenty-five to fifty dollars USD, depending on the exchange rate. Corrugated iron comes from multiple sources. New sheets are available at building supply stores and some hardware retailers. Salvaged sheets circulate through informal markets and Facebook groups where people post available materials from demolition projects. The price for salvaged iron varies wildly based on condition and size. A decent sheet in good shape might go for Gs. 50,000, while a damaged one with holes or severe rust might be given away for free if the buyer arranges pickup. Brick requires a different calculation entirely. The cost includes not just the blocks but the mortar, labor, and time. A family building with their own labor might save on the labor component, but they still need someone who knows how to lay block properly. Poor construction leads to cracks that widen over time, especially on unstable ground. Many of the barrios sit on former floodplain or areas where the soil settles unevenly. I found that structures built without proper foundation preparation, which is most of them, develop structural cracks within three to five years even when the materials themselves are sound.
Regulatory And Legal Context
These constructions exist in a legal gray zone. The land may be owned by the state, by private individuals, or claimed through informal possession arrangements known as posesión. Building codes effectively do not apply in most of these areas, which means there is no inspection process, no permitted material list, and no enforcement mechanism. The consequence is that families use whatever they can afford without regard for fire safety, structural integrity, or health standards. Corrugated iron roofs conduct lightning. Cardboard walls provide fuel for fires that spread quickly between closely packed structures. Electrical installations are typically improvised and rarely grounded. The government has occasionally attempted regularization programs, particularly in Asunción where the Dirección Nacional de Vivienda has run projects to upgrade informal settlements. These programs usually focus on providing formal titles and basic infrastructure like water and sewage access. Material upgrades are secondary and rarely address the core issue of inadequate construction materials. A family might receive a water connection but still be living in a structure made primarily of cardboard and salvaged metal.
What Actually Works Long Term
From what I have observed across multiple projects and visits over several years, the most durable solutions combine materials strategically rather than relying on any single option. A family that replaces their cardboard walls with concrete block on the first floor and keeps corrugated iron roofing but adds a second layer with insulation spacing creates a significantly better living environment. The key insight is that the roof is the highest priority investment. A proper roof protects everything underneath it from water damage, which is the single biggest factor in structure degradation in this climate. Another practical approach involves using sandcrete blocks with a plaster finish on the interior walls instead of cardboard. This costs more upfront but eliminates the replacement cycle and improves thermal performance. The plaster also provides a surface that can be painted, which matters psychologically even if it does not change the structural properties. A white-painted interior reflects more light and makes the space feel larger, which affects how families use and maintain their homes. Corrugated iron remains the most common roofing material for good reason. It is durable, widely available, and can last ten to twenty years if maintained. The maintenance consists of checking for rust spots and applying protective coating before holes develop. I recommended this approach to a community group in Ñemby and provided them with a simple inspection checklist and sourcing information for anti-rust paint. The typical cost for maintaining a corrugated iron roof over a five-year period is around Gs. 500,000 to Gs. 800,000, which is manageable for families earning informal incomes but requires planning that most residents do not currently have.
None of this addresses the fundamental issue that the land these structures sit on may not belong to the people living on it. Material improvements mean very little if the family faces eviction. That is a separate problem with its own set of political and legal dimensions, but it directly affects every decision about what to build and how to invest in a home in these communities.
