In Morocco, there is a serious problem of the estimation of the cost of buildings. In fact, budget overrun is very common. This article describes and analyses a dataset of ratios (cost by square meter) that we elaborated for the estimation of the cost of buildings at an early phase of construction. The ratios also allow to take into consideration the generated cost caused by the integration of insulation materials.

Based on the primary data that were collected by the economic observatory of the provincial delegation of the Ministry of Urbanism, Habitat, Territory and City Policy, we performed our analysis to come up with our own secondary data which are the ratios of the cost (DH/m²). We focused on four elements of the building envelope namely: the external walls, the windows, the roof, and the floor. In fact, Morocco, the cost estimation of construction projects is still imprecise and vague. This causes cost estimation problems (cost/budget overrun) and a lack of vision for all the project stakeholders. Indeed, projects owners, architects and general contractors do not have predefined and precise ratios for specific elements of the building, moreover there are no specific ratios that take into account the additional cost generated by the integration of insulation materials.

The objective of this article is threefold: first, it aims to facilitate the estimation of the cost of the building envelope at an early phase of the construction process by developing ratios (cost by square meter) of 4 different parts of the building. Second, the article aims at estimating the additional cost generated by the integration of insulation materials for the same 4 parts of the building envelope namely: External walls, Roof, Floor and Windows. Lastly, the article aims at calculating the global cost during the whole life of the building by conducting a Life Cycle Cost Analysis (LCCA).

This study is of a great significance for construction economists, architects and general contractors, allowing them to make cost trade-offs between different technical solutions throughout the stages of the building, thus potentially leading to a life cycle cost optimization. In the context of Morocco's building industry, where thermal performance and energy efficiency are becoming increasingly critical (mostly with the energy transition program), the integration of Life Cycle Cost (LCC) and more broadly a Life Cycle Analysis (LCA/environmental aspects) methodologies are crucial. These approaches offer a comprehensive framework for assessing the economic impacts of buildings throughout their entire lifetime: rom material extraction to the end-of-life.

In fact, from an economic perspective, the LCC provides a holistic view of a building's costs over its entire lifespan: this includes, initial construction costs, usage (operational) expenses, maintenance costs, renovation and eventually retrofitting (rehabilitation) and finally disposal or recycling expenses. This approach is particularly relevant in Morocco, where the initial costs of implementing energy-efficient technical solutions, such as appropriate insulation, may be high but can lead to important savings in the consumption of energy and associated costs in the long-term.

By incorporating the cost ratios developed in our study into LCCA models, construction economists, architects and other stakeholders involved in the different construction phases can make more informed decisions about material choices and building design, balancing upfront costs with long-term economic benefits. Indeed, using the cost ratios provided in this study, projects stakeholders can evaluate different insulation options not just based on initial costs, but on their long-term energy saving potential and environmental impacts.

In this sense, we propose a comparison of two different technical solutions for building a Moroccan typical apartment: the first one is based on conventional materials and a second one, based on unconventional (energy-efficient) materials: we compare the different costs generated by each appartement from the initial cost to the end of its life. We take the climate variations, location and all other factors as similar (the only variable that matters is the nature of the building's materials used in the construction process).