NC State School of Architecture, College of Design Campus box 7701, Raleigh, North Carolina, 27695-7701
Title: Mitigating Health Risks Through Moisture-Resistant Wall Assemblies: A Comparative Analysis of Design, Climate and Construction Strategies in Lagos, Nigeria and New Orleans, Louisiana.
Completing this research was possible only because of the immense support, guidance, and encouragement from several individuals and resources.
First and foremost, I would like to express my most profound appreciation to my supervisor, Dr. Traci Rider. Her vast knowledge, experience, and thoughtful critiques have been invaluable throughout this project. What I took to heart most were her well-considered and always-on-target comments that gave me the desperately needed direction.
I owe a debt of gratitude to North Carolina State University for giving me access to invaluable resources and materials that enhanced this research. To the College of Design faculty, your commitment and professionalism made the often intimidating research process a lot easier.
I am thankful for the stimulating discussions with my friends and colleagues here and abroad, which I find intellectually invigorating. It is a joy to have people who inspire me in ways that make me think more critically and spiral to innovate. I sincerely thank Kayode Adeniyi for the time and effort in contributing constructively to this project.
To my remarkable family, your unfailing love, support, and encouragement have been the bedrock of my strength. I cannot express adequately my gratitude for your all-consuming belief in me and the many sacrifices you have made for me.
Finally, I want to acknowledge Abdulahi Opejin, whose support and encouragement have offered me relief, encouragement, and a few “breathers” that have kept me grounded throughout this process.
Abstract
This research project focuses on dampness’s health impacts on buildings, particularly in tropical climates. It examines construction methods and wall assemblies in residential buildings to understand how they might better “protect occupants from moisture-related health risks and harmful indoor air quality.” Pairing two cities with comparable rainfall and temperature but very different construction practices, Lagos, Nigeria, and New Orleans, USA, a model to predict future risk based on a range of extreme weather scenarios and analyzing how changing climate conditions would affect the two localities differently will be developed. These would be analyzed through a five-stage research process incorporating literature reviews, comparative analysis, case studies, simulations, and quantitative and qualitative research methodologies.
Key word: Dampness, Health challenges, Tropical Climate, Mold, Flood, Sustainability.
Introduction
Introduction
Despite widespread attention to and concern about building moisture, much of what is known about this problem is qualitative, conceptual, or anecdotal. Supporting quantitative data would serve several vital purposes (Building Moisture and Durability -PAST, PRESENT AND FUTURE WORK, n.d.). Approximately one-third of households worldwide experience notable issues related to excessive dampness and the widespread growth of mold, leading to substantial health and economic repercussions. Recent advancements in construction methods, alongside more stringent demands for airtightness to reduce energy and control moisture, have significantly impacted the construction dynamics within constructed spaces. This convergence of these factors has presented unparalleled challenges for the built environment (Brambilla & Sangiorgio, 2021).
Tropical regions typically experience very high relative humidity due to their climate characteristics. Factors like proximity to the Equator, warm temperatures, and abundant rainfall contribute to this high humidity. The warm temperatures increase evaporation from oceans, rivers, and forests, saturating the air with moisture. In addition to the frequent rainfall, lush vegetation in tropical
areas also adds to the moisture content in the air. As a result, relative humidity levels often remain high in these regions, hovering around 70-90% or even higher. This high humidity can create unique challenges for residents, affecting everything from daily comfort to health, infrastructure, and agriculture. Managing and adapting built environments to account for this high humidity is essential for maintaining a healthy and functional environment in tropical regions.
Relative humidity is the measure the amount of moisture in the air with the total amount of moisture that the air can hold at a particular temperature (Fleming, 2018). Water vapor is released into the air through precipitation in coastal regions. In contrast, in areas with fewer water bodies, water is blown into the air from the ocean and lake inland by the strong wind patterns (Mariialv, 2014). A region is considered highly humid when the dew point is over 75ׄ°F. This high dew point is regarded as very oppressive. A dew point over 60°F starts to “feel humid.” Dew points under 30°F feel notably arid, with an extreme dryness or lack of water in the air (Abonet, 2021). The extremity of both conditions causes adverse effects on the environment, humans, and their survival.
Dampness in Buildings
Dampness is the continual retention of surplus water within structural components of buildings, including walls, doors, roofing structures, facade materials, and floors, resulting in the deterioration and damage to building elements and can ultimately lead to numerous health challenges as it primarily aids the growth of microbial organisms.
Why is this an important subject of discussion?
Existing literature indicates that tropical climates face numerous challenges related to the built environment and occupant health. Similarly, there has been an increase in concern about the effects of climate change around the world, and much attention is being directed to developing and underdeveloped countries as it poses severe challenges to these regions due to their level of technology and environmental awareness. Here are some of the statements made by concerned international bodies in
World Tropical Regions
Global Humidity Trends
the environmental field.
The health of those who live, attend school, or work in damp buildings has been a growing concern for years (The National Institute of Occupational Safety and Health).
Climate change is one of the greatest threats to humanity. The entire foundation of good health is in jeopardy with increasingly severe climatic events (World Health Organization, WHO).
Studies investigating the relationship between housing and health have been conducted in many developed countries; however, little is known about this in Africa (Agyekum et al.).
In the United States, moisture-related health challenges in buildings are acknowledged
as significant concerns (Environmental Protection Agency, EPA).
Failure to adequately plan for and address these climate changes is anticipated to result in various regional health challenges (WHO, Regional Office for Africa).
Africa faces rising climate-linked health emergencies (World Health Organization, WHO).
Similarly, in Nigeria, many articles have emphasized that climate shifts could induce heat stress, particularly in coastal areas characterized by consistently high relative humidity levels throughout the year. In Ghana, another prominent African country, Agyekum et al. reported that moisture-
and Mildew Growth
Corrosion and Rust of Building Structures
Aesthetic Damage
Damaged Indoor Air Quality
Decreased Comfort
related issues represent a significant structural flaw in buildings across Ghana. All these show the intricacies of this issue and why it has gained widespread attention worldwide.
In addition, dampness contributes to mold and mildew in homes, affecting indoor air quality (Agyekum et al., 2017a). It contributes considerably to building structure corrosion and rust, reducing these structures’ lifespan, functionality, and aesthetic appeal and leading to costly repairs or replacements (Institute of Medicine of the National Academies, n.d.). In many cases, it leads to decreased comfort of occupants and can break out into a range of health challenges.
Relationship with Health
Many health challenges are related to the ineffective design for moisture in tropical climates. Health challenges that affect people in damp buildings include respiratory problems such as asthma, wheezing, and cough; Skin irritation; bacterial and fungal infection; allergies, mycotoxin exposure; and various mental health impacts (Household Mold Linked To Depression, n.d.).
Studies investigating the relationship between housing and health have been conducted in many developed countries. However, much is not known in African countries such as Nigeria and Ghana (Agyekum et al., 2017a; Amoah et al., 2012; Govender et al., 2011)
Question and objectives
Based on this information, the following research questions are to be investigated in this research:
- Does natural disasters such as hurricanes and flooding exacerbate dampness in buildings?
- How does this issue impact the building health and well-being of individuals in realtime?
- How have the affected regions’ building codes been designed to cater to these issues?
- How are the climate characteristics affecting the effectiveness of proposed solutions to managing the effects of dampness?
- How can an architectural designer proffer sustainable solutions to these challenges? This research focuses on how health challenges can be mitigated or managed effectively in flood-prone, high-relative humidity, and tropical coastal regions, and it uses a comparative exploratory approach. Lagos, Nigeria, and New Orleans, Louisiana, acting as the focus areas.
Although these two regions might appear worlds apart, they pose similar environmental properties with high humidity ranging from 72% to 87%, temperature ranging from 800F to 870F, prolonged moisture, and mold exposure due to disasters like hurricanes and flooding, which can lead to respiratory conditions. Both regions also hold a significant number of marginalized and economically disadvantaged people with limited health care and infrastructure.
This research aims to understand, analyze, test, and reflect on the methods and qualities of design and construction practices in these regions. Ultimately, we are probing into more sustainable approaches that can help mitigate the soaring climate issues. These would be approached through five fundamental stage processes: (a) Building case studies in Louisiana and Lagos; (b) building code analysis; (c) flood inundation mapping, quantitative and qualitative survey; (d) Temperature gradient analysis of building wall assemblies, and (e) proposed moistureresistance wall assembly for Lagos, Nigeria climate needs.
The impact of dampness on buildings and communities is a phenomenon that must be understood through the direct analysis of existing buildings in the region, and this was done within the local context and characteristics of Lagos, Nigeria, and New Orleans, Louisiana.
Buiding Case Studies
Building Case Studies
Case Study 1
Mr. Ade’s Flood Damaged Home
Owner: Mr. Ade
Location: Epe, Lagos, Nigeria
Project Timeline: 2017-2018
Status: Damaged/dilapidated
This building was constructed to be a modest home for a middle-income earner. The building is constructed on the natural ground level and typically built with sandcrete walls (made of cement, sand, and aggregates) and corrugated iron roofing sheets. Since the
heating or cooling system in the building. Over time, water accumulates around the building, and heavy rains aggravated it. This constant exposure led to foundation weakening, cracks in walls, roof leakages, corroded wiring, and mold growth, posing a significant health risk to its occupants. From this case study, it was deduced that the building had a structural vulnerability; the building foundation was built without consideration for flood mitigation. In addition to the lack of proper maintenance and high cost of repair, the building became susceptible to moisture damage.
Case Study 2
MakokoFloating School
Architect: Kunle Adeyemi
Location: Makoko, Lagos, Nigeria
Project Timeline: 2012-2013
Status: Demolished in 2015
Although this was a commercial building, it gave a social-cultural analysis of the impact a project designed to solve a problem can bring upon a community, particularly if it fails. This innovative architectural project aimed to provide sustainable education facilities for the vulnerable coastal community of Lagos. It was built on water due to the unavailability of land areas for construction. The structure, made of wood, corrugated iron roofing sheets, and barrels for a free float on waterheld classes for four months, and became a community symbol. However, it started facing critical challenges due to the weather. It eventually collapsed, exposing the design, materials, and maintenance flaws.
Case Study 3
Brad Pitt’s Make It Right Homes
Architect: Frank Gehry, David Adjaye & Shigeru Ban
Location: Lower Ninth Ward, New Orleans Project Timeline: 13 years
Status: Failed
This project was conceived to be solace and comfort to the people affected by Hurricane Katrina. Founded by Brad Pitt in 2007 aimed to rebuild 150 units of sustainable, floodproof homes for those affected by the disaster. There was a collaboration between renowned architects like Frank Gehry, David Adjaye, and Shigeru Ban to create the plan for the buildings. The project failed due to numerous construction issues relating to mold growth, electrical fires, unclean water, and damp walls. This became a devastating scenario for residents who had invested their life savings in the homes. In 2018, after years of deterioration and complaints, a classaction lawsuit was filed against Brad Pitt and the foundation. The negligence of sustainable planning and maintenance over the 13-year project timeline contributed significantly to the project’s failure.
Makoko Floating School
Mr. Ade’s flood damaged home posing health risk
The major takeaways from these case studies include - that all of these projects had design limitations, they had zero sustainability planning, had maintenance deficiencies, had financial constraints, required critical analysis for resilient design intervention, and lacked design for their own specific environmental context.
This substantiate the need to pay attention to numerous environmental and human factors when planning efficient and adaptable design solutions for climate response and resilience.
A prototype of the Make It Right Home.
Makoko Floating School
A prototype of the Make It Right Home.
Buiding Code Analysis:
Lagos, Nigeria & New Orleans, Louisiana
Exterior Walls
Building Code Analysis
A comparative building code analysis of the International Building Code and the National Building Code of Nigeria was explored. This is to establish if there are lapses or discrepancies in the method of construction with regards to eliminating moisture absorption in buildings, causing health challenges in the long run in both regions. The two locations having similarities in climatic characteristics, makes them ideal for this comparative study. They are both tropical regions and have mean annual temperatures ranging from 80.0°F to 87.0°F, mean annual precipitation ranging from 5.2 inches to 26.09 inches, and an average annual percentage relative humidity ranging from 72% to 87%. (Climate & Weather Averages in New Orleans, Louisiana, USA, n.d.), (Lagos, NG Climate Zone, Monthly Weather Averages and Historical Data, n.d.), (Climate New Orleans - Louisiana and Weather Averages New Orleans, n.d.), (Atlas, n.d.). The Nigerian construction sector has standard national building codes for various constructions and building typologies. The government regulates these building codes, particularly the Federal Ministry of Works and Housing. New Orleans, Louisiana, uses the international building codes of the United States of America, regulated by the New Orleans City Council. It also makes use of other standardized codes such as the International Residential Code
(IRC), International Mechanical Code (IMC), International Fuel Gas Code (IFGC), and National Electric Code (NEC) | Code of Ordinances | New Orleans, LA | Municode Library, n.d.; Services - Permits & Licenses
- Building - Guide to Building Permits, n.d. However, IBC is the main subject of focus for this study.
Exploration of the Nigerian National Building Code and The International Building Code Building codes are documents professionally crafted to provide guidelines for the construction sector. They give principles on achieving standard construction to promote safety, eliminate building failures, enhance building integrity, and ensure qualitative housing. (Nigerian National Building Codes)
The Building Code of Nigeria (NBCN) and the International Building Code (IBC) aim to achieve these.
These building codes have specific regulations and guidelines for different moisture-related elements or components, which will be delineated below. Components Nigerian National Building Code International Building Code
- Section 6.2.8.6 Court drainage:
The bottom of every court shall be properly graded and drained to a public sewer or other approved disposal system to comply with the plumbing code listed in the Schedule.
- Section 7.1.1.9.2 Walls within water closet compartments and walls within 800mm of the front and sides of urinals shall be similarly finished to a height of 1.2m, and, except for structural elements, the materials used in such shall be of a type that is not adversely affected by moisture. Materials other than structural elements used in such walls shall be of a type which is not adversely affected by moisture
- Section 8.9.25.3.2.1 Walls: Damp-proofing materials shall be installed on the exterior surface of walls, and shall extend from the top of the footing to above ground level.
Roof Assemblies - Section 6.2.7.1 Enclosed attics and rafters: Each space shall have ventilating openings with corrosion resistant mesh (612mm) to prevent rain1. -
Ventilating area: Roof spaces shall have ventilation openings on the eaves or elsewhere, with corrosion resistant mesh2.Roofs must be sloped for proper water runoff. - Roof drains, gutters, and downspouts are essential.
- Section 1403.2 emphasizes the importance of exterior walls having proper drainage systems to prevent water infiltration.
- Section 1403.2 requires exterior walls to provide a means of draining water that enters the assembly to the exterior
- Section 1405.4 requires flashing to be installed in exterior wall openings and intersections to prevent water penetration
- Section 1405.10 requires vapor retarders to be installed on the warm-in-winter side of exterior walls in certain climate zones.
- The design and installation of roof drainage systems shall comply with Sections 1503.4 and 1611.
- Chapter 15 provides requirements for roof assemblies, including roof coverings, roof insulation, roof ventilation, and roof drainage
- Section 1503.4 requires roof drains, gutters, downspouts, scuppers, and secondary drainage systems to be designed and installed to prevent water accumulation on the roof.
Plumbing Systems. - Section 7.1.1.9.2 In all occupancies, accessories such as grab bars, towel bars, paper dispensers and soap dishes, etc., provided on or within walls, shall be installed and sealed to protect structural elements from moisture.
- Section 9.1.8.28.2.1 When required: before any permit is issued, plumbing plans and specifications are submitted to the code enforcement officer. The plans and specifications shall show the layout and spacing of fixtures; the size, material, and location of all sewers, drains, and piping.
Foundation Drainage - Part 2, section 5.13.1 Vapor barrier shall be installed between the deck and the insulation where excessive moisture conditions are anticipated within the building.
- Section 1507.12 requires roof coverings to be designed and installed to resist the effects of winddriven rain.
- The code requires that roofs be sloped to drain and shall be provided with roof drains, gutters, downspouts or scuppers to convey the rainwater to an approved location away from the buildingSpecific to Louisiana, amendments include:Exception for asphalt shingles on low-slope roofs in cold climates (Section 1507.2.8.2).
- Requirements for metal roof panel underlayment in high-wind areas (Section 1507.4.2). -
Secondary water barrier for wood shakes in high-wind zones (Section 1507.9.1).
- Chapter 29 provides requirements for plumbing systems, including water supply, sanitary drainage, venting, storm drainage, and traps.
- Section 2902.1 requires plumbing fixtures to be provided with adequate water supply and drainage to prevent backflow, cross-connection, and contamination.
- Section 2904.1 requires plumbing systems to be designed and installed to prevent leakage and water damage.
- Section 1805.2 outlines requirements for foundation drainage.
- Foundations in New Orleans must have an effective drainage system to prevent water accumulation
- 8.9.10.5 Protection of concrete: Concrete footings shall be protected from freezing during depositing and for a period of not less than 5 days thereafter. Water shall not be allowed to flow through the deposited concrete.
- Section 8.9.25.5 Subsoil drainage system: Where a hydrostatic pressure condition does not exist, damp-proofing shall be provided and a base shall be installed under the floor and a drain installed around the foundation perimeter.
Crawl Spaces and Basements - Section 5.13.4 Unless otherwise approved by the Code Enforcement Division/Section/ Unit, foundation walls enclosing a basement below finished grade shall be damp proofed outside by approved methods and materials.
-Section 6.2.7.2 Crawl space areas, other than those used as under floor plenums, shall have mechanical or wall openings for ventilation1. Openings shall be near corners and on opposite sides2. The openings shall have corrosion resistant mesh (612mm)34.
- Vapor retarders, ventilation, and insulation control moisture in crawl spaces.
- Local adaptations may address soil erosion and water table fluctuations.
Flood Hazard Areas - Section 8.9.25.8 Erosion protection: Where water impacts the ground from the edge of the roof, downspout, scupper, or other rainwater collection or diversion device, provisions shall be made to prevent soil erosion and direct the water away from the foundation.
around the structure.
- Proper grading, drainage pipes, and waterproofing measures are crucial.
- Section 1805.4 addresses crawl spaces and basements. - Vapor retarders are required on the ground surface in crawl spaces to prevent moisture migration.
- Proper ventilation and insulation are also essential to control humidity levels.
- Chapter 16 provides requirements for buildings and structures located in flood hazard areas, including design flood elevation, flood-resistant construction, flood damage-resistant materials, and flood openings.
- Section 1612.5 requires buildings and structures to be designed and 21
Parapets - Section 5.13.2 Exterior openings exposed to the weather shall be flashed in such a manner as to make them weatherproof. All parapets shall be provided with coping of approved materials. All flashing, counter-flashing and coping, when of metal, shall be of not less than 26 gauge corrosionresistant metal.
Frost Protection/ Waterproofing weather exposed areas
- Section 5.13.3 Balconies, landings, exterior stairways, and similar surfaces exposed to the weather and sealed underneath shall be waterproofed.
constructed to resist the effects of flood loads, including hydrostatic, hydrodynamic, and debris impact loads.
- The code requires that parapets of a minimum height be provided on roofs with aggregate surfacing to prevent blow-off of the aggregate.
- Section 1507.12 requires the minimum height of the parapet to be 30 inches (762 mm) above the roof surface at the eave and rake edges.
- The code requires that foundations and other permanent supports of buildings and structures be protected from frost by one or more methods specified in Section 1809.5 . - Egress doors are also required to have frost protection in accordance with Section 1809.5.1.
Windows - Section 6.2.1.1B Every room or space intended for human occupancy shall be provided with natural and/or mechanical ventilation.
- Section 6.2.4.2 The minimum openable area to the outdoors shall be 4 percent of the floor area being ventilated.
- Section 6.2.7.2a Openings shall have a net area of not less than 0.1m2 for each 15m2 of foundation space. Where an approved vapor barrier is installed over the ground surface, the required net area of openings shall be reduced to 10 percent of the above and vents shall have manually operable louvers.
- Section 6.2.7.3 Alternative mechanical ventilation: Enclosed
- Chapter 24 of the IBC outlines requirements for glazing subjected to wind and snow loads.
- Glass sloped 15 degrees or less from vertical in windows, curtain and window walls, doors, and other exterior applications must be designed to resist wind loads based on the basic design wind speed (V) specified in Section 1609 for components and cladding.
attic, rafter, and crawl spaces that are not ventilated as herein required shall be equipped with a mechanical ventilation system conforming to the requirements of the mechanical code listed in the Schedule.
Floors - Section 7.1.1.9.2 Floors in water closet compartment and showers: In other than dwelling units, toilet room floors shall have a smooth, hard, non-absorbent surface such as Portland cement, concrete tiles or other approved material which extends upward. onto the walls at least 127 mm
- Section 8.9.25.3.1 8.9.25.3.1
The required damp-proofing materials shall be installed between the floor and the base as provided by Section 8.9.14.5.1 except where floor is provided above a concrete slab
- Section 8.9.25.3.2 Floor dampproofing materials: Under the slab, use 6-mil polyethylene or other approved materials with 150mm-lapped joints. On top of the slab, use mopped-on bitumen, 4-mil polyethylene, or other approved materials. Lap and seal membrane joints as per manufacturers.
- IBC Section 1805 Protection of Elements in Contact with the Gr oundElements such as walls, floors, and structural components that come into contact with the ground must be safeguarded. - Depending on the water level, these components should be either waterproofed or damp proofed as required by the current codes.
Waterproofing and Damp-Proofing
- Section 8.9.25.1 Where required:
Walls or portions thereof, retaining earth and enclosing interior spaces and floors below grade shall be waterproofed and damp-proofed according to this section, except those spaces containing uses other than residential and institutional where such omission is not detrimental to the building or
- IBC Chapter 14 & 15 Section 1805 All elements in contact with the ground, including walls, floors, and structural elements, must be protected. Depending on the water level, these components are to be waterproofed or damp proofed.
- Section 902.3.4 The construction process itself should not allow moisture from the building materials or theatmosphere to cause any
Ground Water Control
occupancy. permanent damage to structural or nonstructural building elements.
- Section 8.9.25.2 The owner or applicant shall perform a subsurface soil investigation to determine the possibility of the ground water table rising above the proposed elevation of the floor or floors below grade.
- Section 8.9.25.2.1 Where the groundwater table is lowered and maintained at an elevation not less than 150mm below the bottom of the lowest floor, the floor and walls shall be damp-proofed in accordance with Section 25.24.3
- Section 8.9.25.4.2.2 Wall waterproofing materials: waterproofing shall be applied from the bottom of the wall to not less than 300mm above the maximum elevation of the groundwater table. The remainder of the wall shall be damp-proofed in accordance with Section 8.9.24.3.2.2.
The comparative analysis elaborated on the provisions of the building codes that were designed and documented to mitigate water infiltration in buildings. From this analysis, the following were observed.
- Both building codes emphasized the importance of efficient drainage systems to prevent water accumulation around buildings/structures.
- They both emphasize using waterproofing materials in areas prone to moisture infiltration, such as basements and foundations.
- To reduce condensation and maintain good indoor air quality, both codes documented the need for adequate ventilation provisions.
- Proper site grading and sloping away from the building to direct water runoff are
- Subsurface soil investigation is required to determine whether the existing ground-water table is above or within 5 feet (1524 mm) below the elevation of the lowest floor level where such floor is located below the finished ground level adjacent to the foundation.
standard requirements in both codes.
- Both building code systems emphasized sealing joints, windows, doors, and roofing to prevent water penetration.
- Lastly, both building code systems advocated regular inspection and maintenance to identify and address potential moisturerelated issues early.
Although these were documented in the codes, from the case study done in both Lagos, Nigeria and New Orleans, Louisiana, it is observed that the real-life practices do not often follow the requirements documented in the book. There were technical negligence in applying numerous codes, particularly in Lagos, Nigeria.
Flood Inundation Mapping, Quantitative and Qualitative Survey Analysis of Lagos, Nigeria
Flood Mapping
Using Google Earth Engine (GEE) script and visualization interface, a flood analysis was done on Epe, Lagos State, Nigeria. Epe is one of the regions most affected by floods in Lagos, Nigeria. In a flood vulnerability assessment and mapping of Lagos State, Epe was identified as having 143.42 km2 of its 875.20 km2 land area at high flood risk, which accounts for approximately 16.39% of its total land area.
This satellite-based flood assessment used Sentinel-1 SAR data (COPERNICUS/S1_GRD) with scripts that applied speckle noise filtering, flood inundation mapping, and water body detection. Its interface included a script editor where the flood detection algorithm is written in JavaScript, a console showing outputs such as the flooded area and the number of flooded houses, and a map visualization displaying flood inundation and water bodies.
This type of analysis is typically used for disaster management, urban planning, and environmental monitoring. Due to the lack of detailed annual flood data for Lagos, Nigeria, this model was used to acquire past years’ flood data and predict future flood data of Epe, Lagos State, Nigeria. The analysis is performed for three consecutive years (2022, 2023, and 2024) to identify flood severity, impact, and most affected regions in much more detail.
This information assisted in categorizing the predominantly flooded region susceptible to continuous dampness and helped streamline areas to concentrate other research activities, including further case studies and survey analysis.
Graphically, in the images, the red marks indicate the flood inundations, whilst the blue marks represent water bodies.
Quantitative
and Qualitative Analysis
This section provides a concise overview of the research, including the survey design, data collection, and analysis methods.
The study employed a mixed-methods approach, combining quantitative surveys and qualitative interviews to assess the prevalence of moisture, its causes, and its impact on buildings across Epe, Lagos. A well-structured questionnaire was developed to obtain data on - the extent of moisture-related problems (e.g., dampness, mold, water infiltration)
- the causes (e.g., construction materials, drainage conditions, climate factors)
- the effects on residents (e.g., health issues, structural damage, maintenance costs).
- Current mitigation efforts being made by homeowners, businesses, and authorities. The survey contained open-ended questions, allowing for statistical analysis and deeper insights into respondents’ experiences.
Sample Population & Data Collection
The study targeted homeowners, tenants, and building professionals in Epe. With 70 respondents, a random sampling method was used to ensure representation across different socioeconomic groups. The typology of the building targeted was residential.
Data Analysis
All quantitative responses were analyzed using statistical tools to identify trends in moisture-related challenges, and all qualitative responses were categorized to highlight recurring themes, challenges, and solutions. Findings were referenced with existing literature on building codes, urban resilience, and flood-prone areas.
Limitations to the Study.
There were some limitations recorded for this study, such as
- Some respondents may have underreported or overstated the moisture issues they experience.
- The study is focused only on Epe; results may not be fully generalizable to other areas.
- Seasonal variations in rainfall were not accounted for in the survey timing.
Four key factors were upvoted by the Epe residents who participated in the survey for this research. Digging in-depth into their characteristics and ways they can be responded to, They are:
- Issue of bad constructions
- High relative humidity
- Natural disasters such as flooding
- Weak walls.
Temperature Gradient Analysis of Building Wall Assemblies, Lagos & New Orleans.
Climate Data for Epe, Lagos State, Nigeria - Cumulative Average
Climate Data for New Orleans, Louisiana, USA - Cumulative Average
Climate and Building Assembly Performance
A comparative analysis of temperature gradients and moisture movements within wall assemblies in Lagos State, Nigeria, and New Orleans, USA, was conducted using climate data from Climatedata.org.
The temperature gradient analysis for both regions was calculated using parameters such as the Inside temperature, 0F (temperature within the building interior), Outside temperature, 0F (temperature of the external environment), Delta T, 0F (temperature difference between the inside and outside environment), Dew Point, 0F (temperature at which condensation occurs within the wall assembly), External Relative Humidity, % (level of humidity in the outdoor air, which affects moisture movement), Cumulative R-Value (total thermal resistance of the wall assembly layers), R-Value per Layer, % (contribution of each material layer to the total thermal resistance), R-Value per Inch (thermal resistance per unit thickness of each material), alongside the wall assembly layers used in Lagos Nigeria and New Orleans, USA. The analysis examined how different wall assemblies respond to environmental conditions, highlighting the risks of condensation and the implications for building durability and indoor air quality. 34
Key Findings
Lagos, Nigeria:
Wall assemblies in Lagos are particularly vulnerable to condensation due to the region’s consistently warm and humid climate. This study identified a significant temperature differential of -13.50F (for the month of April) between indoor and outdoor environments, leading to recurring condensation at the dew point, notably all year round. Traditional construction practice, with the use of hollow sandcrete blocks and cover of cement plaster, entraps moisture within walls, leading to a high propensity for structural deterioration, mold growth, and overall indoor discomfort. Alteration of these assemblies through the addition of rock wool insulation and increased wall thickness has proven a successful intervention that effectively restricts condensation and moisture thereby improving moisture control and comfort indoors.
New Orleans, USA:
In New Orleans, Louisiana, temperature variation is relatively insignificant, at a mere -1.40F for the month of April, and significantly lessens condensation risk. The standard construction materials in the city include wood stud walls with cavity
Analysis
A data showing condensation action all year round within the 6-layer wall assembly in Lagos, Nigeria.
A graphical data of condensation action in wall assembly all year in Lagos, Nigeria.
insulation in the form of fiberglass batts and siding in cypress wood, providing ideal moisture resistance, which helps to maintain stable indoor conditions. Additionally, using gypsum boards and well-insulated cavities helps reduce thermal bridging, effectively controlling excessive moisture in the building envelope. The array of materials and design choices enhances the durability and comfort of New Orleans’ climate to a large extent.
Comparative Insights
- Lagos faces a heightened level of condensation with its high humidity and more significant temperature gradients, which will, therefore, necessitate increased insulation and material selection to counteract moisture-related complications.
- According to the analysis, New Orleans’ building practices are better suited for moisture control based on the climate characteristics, demonstrating their effectiveness in reducing condensation
through cavity walls with insulation and vapor-permeable materials.
- Implementing climate-responsive strategies, such as efficient insulation, vented buildings, and moisture-resistant materials, is critical to make buildings in humid environments durable and sustainable.
A data showing condensation action all year round within the 7-layer wall assembly in New Orleans, USA.
A graphical data of condensation action in wall assembly all year in New Orleans, USA.
Analysis of the modified wall assembly for Lagos: If the temperature at the outer edge is less than the dew point temperature, condensation will occur. If the dew point temperature is less than the temperature at the outer edge of the wall assembly, then there will be no condensatoion.
A data showing condensation action all year round within the modified 7-layer wall assembly for Lagos, Nigeria.
A graphical data of condensation action all year round in the modified wall assembly for Lagos, Nigeria.
Design Approach
Proposed MoistureResistance Wall Assembly for Lagos, Nigeria Climate Needs.
Design Approach
Moisture-related degradation is undoubtedly a significant issue in Lagos, which impacts both building structures and human health from the analysis executed, but rather than view it just as a problem, it can be considered as an opportunity to revise the design strategy to implement a more resilient, cost-effective, and sustainable building. What is required is an improved wall assembly design that actively works to mitigate risks associated with moisture while being economically viable as well as sustainable. The proposal for a better wall assembly considers the humid or flood conditions prevalent in Lagos for structural durability and comfort to make the structures safe for occupants.
Proposed Wall Assembly
The system incorporates three key elements
1. Double-layered hollow Sandcrete Blocks with an Air Space for Insulation and aeration.
Why Sandcrete?
Sandcrete is popularly used in Nigeria due to its affordability and readily available materials. However, the wall gradient analysis shows that single-layer sandcrete walls are susceptible to absorbing and retaining moisture.
A double-wall system introduces an air cavity
between two layers of hollow sandcrete blocks. The cavity will act like a thermal and moisture buffer that reduces heat transfer and prevents condensation from building up within the walls. The ventilation gap will also contribute to the dispersion of trapped moisture, reducing further chances of mold growth and structural degeneration.
2. Plaster Coatings to Prevent Water Seepage.
Exterior Protection:
A layer of water-resistant cement plaster applied to the external surface seals the wall against direct water infiltration from rainfall and flooding.
Interior Protection:
The smooth plaster finish inside the building prevents moisture absorption from the external wall. Using lime-based or breathable plasters allows controlled vapor movement internally, minimizing internal condensation by not trapping moisture.
3. Raised Foundation Footing to Reduce Flood Impact Foundation Elevation: Elevating the foundation footing of the structure by at least 0.5 to 1 meter above the potential flood levels reduces the possibility of direct seepage of water. This is important in flood-prone neighborhoods where stagnant water after heavy rains is a
common challenge.
Improved Drainage System: Weep holes at the bottom of the outer walls with flashing allow the easy drainage of water that seeps into the wall rather than retaining inside the structure. Subsurface drainage systems around the foundation can divert water away from the building
Current Above-ground Wall Assembly Design
Current Above-ground Wall Assembly Sectional Design
Every research journey has challenges, and this study was no exception. While valuable insights were gained, several limitations impinged on the depth and scope of my findings. These include: Inability to Conduct Field Studies in New Orleans and Lagos
Initially, I considered traveling to both locations for an on-site field study, which would have allowed me to:
- Directly observe building conditions and moisture-related damage.
- Conduct interviews with affected residents, builders, and policymakers.
- Assess personally the impact of climate, material used, and construction methods. However, due to logistical issues, such as time, finance, and accessibility, I had to use secondary data, reports, and previous case studies. Though it gave valuable insight, an in-depth field study would have strengthened my findings.
Scope of Literature Review and Accessibility of Study Materials
While I did an extensive literature review, the research could have been broader by accessing more case-specific studies dealing with moisture control and flood mitigation in Lagos and New Orleans.
Many technical reports, academic journals, and government planning documents were restricted, unpublished, or inaccessible, particularly for Lagos.
Some case studies focused on general climate resilience but did not give detailed analyses of moisture impact on health and building performance, a core area of interest.
Challenges in Sourcing Comprehensive and Relevant Materials
Information on traditional moisture control methods in Lagos and post-Katrina reconstruction efforts in New Orleans was scattered across various sources.
Data inconsistencies between regional reports and international studies sometimes required cross-referencing to verify findings. Access to interviews, historical building performance data, and long-term impact assessments were incomplete. While these limitations in no way diminished the value of the research effort, they represent areas where further investigation and collaboration might further develop the depth of future studies and translate the findings into practical uses.
Future Plans
Despite these challenges, this research laid the foundation for key next steps. As I proceed, this work will result in a published piece that can add valuable knowledge to architectural science, sustainable design, and climate resilience. I also plan to learn further by researching buildings that are in flood-prone regions.
Beyond pure research, I am interested in acquiring practical experience on how actual buildings have successfully incorporated moisture control strategies. I would like to explore the analysis of how structures in different climatic zones are built to control flooding, humidity, and moisture damage; I will also want to explore how sociocultural, socioeconomic, and other environmental factors can impact natural disasters, thereby facilitating discussions and research that help mitigate their impacts.
References
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