Comprehensive strategies and thoughtful, immediate, and practical action plans are crucially required to make a difference in the challenges the building industry currently faces and to avoid future adverse outcomes. Objective plans should be taken into practice to lubricate the transition using appropriate supportive tools, such as indicators, checklists, toolkits, etc. The idea is to enhance the resulting strategies and plans in the construction processes and ensure they are harmlessly practicable, aiming to achieve healthy, sustainable concepts. Therefore, to provide example toolkits for the healthy selection of materials, the following section presents formulations of the previous statements in practical applications.

Based on previous practical and analytical discussions, and in line with the Paris Agreement (2015) and the SDGs [205], sustainable concepts of the building processes for objective systems, including construction parts, should incorporate and prioritise the users’ health. Thus, the target for this objective system here is a “programmable CS” (PCS), dynamic CSs that are adjustable for health, biodiversity, economy, industrial ecology, etc., and safeguard a healthy forthcoming built environment. Similarly, Refs. [113,206] specified a long-term perspective as the only difference between liveability and sustainability. Thus, sustainability is a decent measure for the planet’s health and inhabitants. Figure 6 also shows that occupants’ health can be ensured by examining and checking the sustainability pillars.

Regarding the pillars of sustainability, the economic situation of the users and the housing on a global scale are out of the scope of current research. However, the economic aspects predominantly related to the building industry incorporating the land use (i.e., indirectly), construction, materialisation, etc., that are relevant here can be checked concerning health within the scheme in Figure 6. Environmental health checks also focus on the built environment and housing, which targets CMs. Following the path of PCSs, the latter will be in the form of programmable construction materials (PCMs). Returning to the sustainability pillars, the social WB of the scheme only checks the health and desire regarding the construction of houses. The summary of the processes of providing materials for the construction in Figure 5 is applicable for analysing housing stocks as a significant portion of the building industry. Therefore, to base the PCSs for health on a broad scale, checking the impacts of the materials’ production processes with the three well-known components of sustainability could be an example of, and a summarised indicator for, the selection of materials. Programming PCMs for health is a vital consideration; thus, the mentioned checking tool is the health-oriented selection of PCMs, or HS-PCMs, shown in Figure 7. This generative, simple, practical concept toolkit examines the health aspects of construction. It is easily developable into a sub-element.

The HS-PCMs is a general concept directly applicable to the mesoscale (i.e., construction). However, owing to its generative nature, it could also be further detailed for the application on the microscale (i.e., materials). 

To ensure the concept’s viability, it will also be tuned to circularity. Choosing the circular economy as the best way to battle climate change and take the strategies into action means it is the only way to make modern life healthy (see the pillars of the circular economy in Figure 8). Julie Hirigoyen (2016), CEO of the UK Green Building Council, states that transferring the circular economy to the building industry will decrease resource consumption and adapt various applications while providing healthier living and workspaces. Similarly, Cheshire [207] emphasises the healthy built environment as an advantage of the circular economy, resulting in significant economic returns for ownership costs. Examples are provided here, depending on the sustainable solutions and support for transitions into a circular framework. The same method that health issues are previously checked with sustainability pillars in a sample case (e.g., scheme in Figure 7) is also applicable to inspect them with the circular economy pillars (Figure 8). A concept (to demonstrate the simplicity and effectiveness of practical applications) to make a toolkit out of a collection of these checking criteria is shown in the scheme of Figure 9, which is similar to the HS-PCMS (the scheme in Figure 5), which can be used with the circular economy.

Thriving emerging solutions include alternative CMs, evaluation criteria capable of public applications, and high-tech solutions for healthier PCMs based on renewable and sustainable sources.

This section concentrates on an appropriate compatible alternative that could be used as the third target material after steel and concrete (i.e., those currently dominant in the market) to facilitate transitions towards healthy PCMs. The alternative must be suitable for replacing CCMs on a vast scale. Bio-based materials have been implemented for use in sheltering humankind for our entire history [208]. It is the source of environmentally friendly CMs that are primarily harmless [209] and harvestable, only consuming a minor amount of energy [210]. The platform of bio-based materials contains two main categories: biodegradable and bio-sourced materials.

Because of the sustainability aspects of these low-impact healthy materials, their bio-based applications in the building industry are advancing considerably. Examples include Eindhoven’s growing Pavillion, 2019; Hy-Fi tower of “The Living” in New York, 2014; HempHouse in Nashville, 2010; etc. Hence, their variety is also enlarging, going beyond the scope of this research. Therefore, only wood belonging to the second bio-based category is discussed here as an alternative replacement for abiotic materials on a public scale. Wood, in general applications, is the most widely used material [211]. In addition to being the most sought after by humans [212], this material comes from the most renewable resource on the planet [213,214,215,216,217]. Therefore, it belongs to the very sustainable group of natural sources (e.g., Figure 10) due to its carbon sequestering and low energy consumption; compared with CCSs, it is very quickly renewable [218]. The new generations of timber are lightweight, robust, durable [215,216], and applicable in prefabricated buildings. However, due to historical issues (e.g., centennial large city fires) [219,220,221], timber was gradually removed from the modern construction market as a result of the disadvantages in its technical characteristics, as well as its other limitations [222]. Nevertheless, new advancements in timber technology caused drastic developments, creating innovative high-tech timber [223], which is also compatible with the cutting-edge technologies transferable for PCSs. However, applications in new houses are not equally growing with these advances (e.g., only 25% of the UK’s newly built houses are timber-based).

This study attempts to benefit from the effects of nature on mental and physical health, conducting research in construction-related directions. The connectivity of WB with the natural environment is a proven fact [224,225,226,227,228,229,230,231,232]. In the built environment, biophilic, -mimetic, and other bio-inspired concepts that were first designed for the recovery of patients [231], are famous examples of nature’s effectiveness on WB. Researchers at Michigan University observed that the productivity of office workers increased by 20% after spending one hour in nature [230]. Hence, the U-M’s researchers also examined students’ test results and found that 20% of the students improved their scores after walking through nature [230].

Further studies show similar effects on improving the memory of people diagnosed with depression, etc. Therefore, logically, as a part of nature, according to Dematte et al. [221], timber is much closer to human feelings and sensations than any synthetics. Users’ emotions directly influence their mental states [139]. In addition, the link between happiness and health has been excessively studied and proven (e.g., Refs. [233,234,235,236,237,238]). Similarly, Nyrud et al. [239] and Nyrud et al. [240] studied the influences of wood on patients’ health; they observed positive impacts. Hence, Cronhjort et al. [241] examined the effect of timber on the interior of buildings; in blind testing, positive influences on participants’ feelings were the primary outcome.

The effectiveness of wood on people’s psychological health has also been investigated by Burnard et al. [242] and Dematte et al. [221]. Surprisingly, many researchers confirm that wood surfaces, compared with other CCSs, more effectively confine microbial growth and minimise microbial transmission [243,244,245,246,247]. The study regarding the effects of exposed surfaces on hospital patients performed by Munir et al. [247] proved that using wood in such applications reduces the requirements for chemicals and antimicrobic agents for daily cleaning. Based on the analysis of Alpert [248], microbes on timber will face desiccation due to wood’s absorption properties. Hence, unhealthy and damaging microorganisms are withdrawn or even killed by the extractive components of wood’s tissue [249]. Although the study of Munir et al. [247] focuses on natural and untreated wood, it proves its effectiveness. They argue that due to wood’s hygroscopicity properties, microbes are stuck in this material and thus cannot contaminate food or other contacts. Hence, the absorption characteristics of timber trap microbes and prevent reproduction and colonisation [250].

According to Munir et al. [247], the porosity of wood, which was always discussed as a negative parameter in timber, is favourable for its hygroscopicity that causes unfavourable living conditions for microbes and even for some typical bacteria. Each of these natural materials resembles humankind’s affinity with uniqueness. However, inherent beauty features, cleanliness, and reactions towards microorganisms in different wood species vary [247]. However, all timber embodies a certain level of hygroscopicity and antimicrobial chemicals to engage positively in users’ health. Therefore, if the properties and capacities of the emerging technologies allow for a massive market, this restorative material is an effective option for the transitions.

The effectiveness of wood in the modern CSs has been proven (e.g., Refs. [241,251,252,253,254,255]). For example, Jayalath et al. [256], by conducting experimentations and analyses in three major cities in Australia on midrise buildings, approved the environmental efficiency of advanced mass timber over the CCSs. In principle, high-tech timber has provided two essential opportunities for the housing sector (and most other sectors).

Mass timber (MT): these are production techniques that can be applied on an extensive scale; they are crucial solutions for housing units, for example, for the demanding housing market of the Netherlands (see Ref. [42] for analysis). The category of mass timber, which was primarily established as a framing style, currently uses large, dense wood panels for walls, floors, and roofs, and even in column construction. Additionally, employing a combination of digital design, CNC processing, and other modern techniques, such as 3D printing and lasers, the market for mass timber is further enlarging and encompassing almost all types of buildings.

The engineering of mass timber (e.g., see examples of some high-tech mass timbers in Table 5), in addition to the old systems, such as modular concepts developing in the novel and emerging techniques [257], creates a new wave of advantages for the PCSs based on high-tech mass timber.

Healthy PCMs also require certain properties. Therefore, a summary of some technical characteristics and practical features for the new, high-tech mass timber, compared with conventional materials, is provided in Table 6.

Some of the abovementioned mass timber technologies have already confirmed their unique qualities. For example, GluLam and CLT have been implemented even in large-volume construction and high-rise buildings (e.g., Dalston Lane in London, Forté in Melbourne, Brock Common in Vancouver, HoHo in Vienna, T3 in Minneapolis, the Kajstaden in Västerås Sweden, etc.). Therefore, mass timber can sustainably fulfil the current scale of demands for housing at a rapid pace with agility, sustainability, and resilience, which are crucial for a successful transition [258]. Although mass production after the Industrial Revolution [259] caused most of the adverse effects on the environment [113,260,261,262,263,264], mass timber is based on relatively quick renewable sources [223,265,266,267]. The historic obstacles were fire and decay. Fire has a long history regarding buildings [222]. Naturally, wood decays in various ways, including through weathering, insect infestation [268], and fungal decay [269]. However, modern timbers have overcome the old complications [270,271].

Nevertheless, in addition to the study of Igarashi [272] and Feldhoff [273], which recognised the lobby in Japan’s construction market against sustainable products, Kaiser [271] identifies the poor regulations that relate to the returning of wood into the building industry on a global scale. He emphasises the high qualities and potential of new generations of CLT that meet the building requirements [271]. Studying the Swedish construction sector, Hemstrom et al. [274] also show the necessity for some governmental regulation and intervention to accomplish successful innovative transitions. Similarly, in the Netherlands, new policies such as BENG 1, 2, and 3 with the TOjuli, functioning from 01.01.2021, tighten the advanced CS regulations to provide more room for the CCSs. Thus, the technical (tested in Section 4.5.) and social (examined in Section 4.4.) characteristics of the innovative renewable alternatives for CMs, such as timber for public use, do not seem to be adequately appreciated.

In addition to the interconnectivity of health and occupants’ satisfaction, the users’ desire is a critical priority for the PCSs concerning WB and the economy. Addressing health ensures the durability of a specific construction system (CS) or construction material (CM) in the market. Therefore, social preferences are considered a significant component of the objective PCMs’ establishment. In this regard, brief, abstract results from comprehensive research (see the subsequent investigation in Shahnoori et al. (2022)) are presented here. The PCMs are tools under a comprehensive strategy for healthy evolving CSs. To examine the method in various aspects, extensive questionnaires and interviews were conducted. Gradually, more than 750 users submitted their reactions; however, around 500 results were incorporated in this article due to time constraints. In the first phase of the field research, the questionnaires about the people’s interests in three materials (CMs), namely steel, concrete, and timber, were delivered without providing extra information about the characteristics of the CSs. However, some critical features of advanced mass timber were presented to the interviewees in the second round. The results towards timber dramatically and positively changed. The other noticeable difference between the two research rounds was the age classification. In the first round, older adults were the most common group, while all age groups were equal in the second round. Discussing the societal-related study in detail and its analytical arguments is beyond the current article’s scope. Therefore, only the summary of outcomes of the research on social interests is shown in Table 7. A comparison of the male and female participants’ preferences for the same case is demonstrated in the chart in Figure 11.

Advanced mass timber techniques, such as the CLT (Cross Laminated Timber), GLM (Glue Laminated), LVL (Laminated Veneer Lumber), etc., demonstrate higher qualities than the CCMs. However, qualities are relative and should be comparatively evaluated. Hence, the advances in mass timber technologies are progressive and at a rather rapid pace. They come from renewable sources [275]. Their carbon footprint is at least 50% lower than CCMs. Their life-cycle assessment and end-of-life scenario confirm their healthy advantages [276,277,278,279]. As an appropriate case of applied, sustainable, and healthy CMs, the Sara Cultural Centre is partly evaluated according to the PCMs (see Table 8). The 76 m 20-story building is currently one of the world’s tallest timber buildings (i.e., the fourth tallest), containing GLM columns and CLT walls, and it is located in Skelleftea, Sweden. Constructed from 12,200 cubic meters of wood, it also uses carbon-neutral energy via solar panels, batteries, and a heat pump that works with electrical, water, and district heating. The fire compartment system (i.e., the charring capacity of wood) is also powered by renewable energy (White Arkitekter, 2021). Thanks to the wood structure, the carbon emissions for lighting and thermal comfort are less than 50% of the carbon sequestering in the construction. With more than 100 years of service life span, the building will continue sequestering carbon for more than 50 years (GCR, 2021). Similar cases, such as the 85.4 m tall Mjøstårnet in Brumunddal, 100 km north of Oslo, or the Treet Tower in Bergen (Damgårdsveien 99), are increasingly being developed across the globe.

Yet, with identical performance characteristics of the CLT compared with CSs, such as concrete, it is 80% lighter, affecting transportation, energy use, time and velocity, safety, etc. Hence, the mentioned CO₂ reduction is natural and does not incorporate extra MAC (marginal abatement costs). In addition to the seismic performance and ductility of the joints, CLT and GLT do not transmit heat and cold, which disturb the indoor thermal balances.

As also shown in Table 8, although the HS-PCM toolkit is at the concept level and early development stage, it is already applicable for a general evaluation of the health aspects of various phases of a construction case based on sustainability pillars.