Table 1
Overview of the most relevant methods (steps, assessment criteria and factors of disassembly criteria).
| ASSESSMENT METHOD | NUMBER OF STEPS TO COMPLETE | ASSESSMENT CRITERIA, TOTAL | FACTORS OF DISASSEMBLY CRITERIA |
|---|---|---|---|
| Durmisevic et al. (2003) | 7:
| 48 |
|
| Cottafava & Ritzen (2021) | 4:
| 10 |
|
| van Vliet (2018) | 4:
| 8 | MCI
|
| van Vliet et al. (2021) | 4:
| 4 |
|
[i] Note: For a comprehensive table and details, see Appendix 1 in the supplemental data online.
Figure 1
Research design: materials, methods and results.
Table 2
Case study building information and evaluated data.
| LITTLE FINLANDIA, ‘FIN’ | POSTIVARIKKO, ‘POS’ | VÄRE MODULE J, ‘VAR’ | |
|---|---|---|---|
| Image of BIM data |  |  |  |
| Location | Helsinki | Helsinki | Espoo |
| Construction year | 2022 | 2023 | 2018 |
| Design service life (years) | 30 | 50 | 50 |
| Floors | 1 | 1 | 5 |
| Heated net floor area (m2) | 2,622 | 1,205 | 1,417 |
| Building type | Multifunctional building | Assembly building | Educational building |
| Construction type | Volumetric unit | Post and beam | Prefabricated element |
| Primary material | Wood | Wood | Concrete |
| Utilised BIM data | Contractor final BIM model, 20 January 2021 | Architect + Construction engineer final BIM model, 7 April 2022 | Architect + Construction engineer final BIM model, 24 January 2019 |
| 11 Site elements | – | – | – |
| 121 Foundations | – | – | – |
| 122 Ground floors | ○ | ○ | ○ |
| 123 Structural frame | ○ | ○ | ○ |
| 1233 Columns | ○ | ○ | ● |
| 1234 Beams | ○ | ○ | ● |
| 1235 Intermediate floors | ○ | ○ | ● |
| 124 Facades | ○ | ○ | ○ |
| 125 External decks | ○ | × | × |
| 126 Roofs | ○ | ○ | ○ |
| 131 Internal dividers | ○ | ○ | ○ |
| 132 Space surfaces | ○ | ○ | ○ |
| 133 Internal fixtures | – | – | – |
| 134 Other internal space elements | × | × | × |
| 135 Box units | × | × | × |
| 2 Services elements | ○ | ○ | ○ |
[i] Note: ● = Building information model (BIM) data quality allows for individual product-based disassembly potential (DP) assessment; ○ = BIM data quality allows for quantity take-off-based DP assessment; ‘–’ = BIM data do not allow sufficient information for either type of DP assessment; ‘×’ = BIM has no relevant data.
Table 4
Identified primary materials and construction systems with the selected type joints for interviews.
| PRIMARY MATERIAL/CONSTRUCTION SYSTEM | WOOD | CONCRETE | HYBRID |
|---|---|---|---|
| Beam-column and slab |
|
|
|
| Load-bearing wall and slab |
|
|
|
| Spatial element |
| – | – |
[i] Note: For full details, see Appendix 3 in the supplemental data online.
CLT = cross-laminated timber.
Table 5
Example of the material list and evaluation of a type joint 6 with the proposed method.
| ASSEMBLY | RESOURCE | RESOURCE MASS/GWP | ACCESSIBILITY (Ca) | CONNECTION TYPE (Ct) | DPr |
|---|---|---|---|---|---|
| Load-bearing wall | CLT | Mass (kg)/GWP (kg CO2e) | 1.0 (no obstructing layers) | 0.6 (screw) | 0.75 |
| Intermediate floor | Concrete floor cast | Mass (kg)/GWP (kg CO2e) | 1.0 (no obstructing layers) | 0.1 (cement mortar) | 0.18 |
| RIB LVL beam with internal insulation | Mass (kg)/GWP (kg CO2e) | 0.6 (screw-attached layer) | 0.6 (screw) | 0.60 | |
| Gypsum board | Mass (kg)/GWP (kg CO2e) | 1.0 (no obstructing layers) | 0.6 (screw) | 0.75 | |
| Exterior wall | CLT wall | Mass (kg)/GWP (kg CO2e) | 0.4 (nail-attached layer) | 0.6 (screw) | 0.48 |
| Timber cladding | Mass (kg)/GWP (kg CO2e) | 1.0 (no obstructing layers) | 0.4 (nail) | 0.57 |
[i] Note: For the utilised values, see Appendix 7 in the supplemental data online.
CLT = cross-laminated timber; GWP = global warming potential; RIB LVL = rib panel.
Figure 2
Type joint 6 for assessment.
Note: For full details, see Appendix 3 in the supplemental data online.
Figure 3
Expert interview evaluations of type joint accessibility and deconstructability.
Table 6
Expert interview second-round results intraclass correlation coefficient (ICC) (2,k) values reported based on a two-way random-effects model, assessing for absolute agreement among raters.
| VARIABLE | ICC | LOWER CI | UPPER CI |
|---|---|---|---|
| Experts: Accessibility | 0.90 | 0.79 | 0.97 |
| Experts: Deconstructability | 0.92 | 0.83 | 0.97 |
| Experts: Normalised, proposed method | 0.92 | 0.82 | 0.97 |
[i] Note: CI = confidence interval.
Figure 4
Type joints assessed by the proposed method and Dutch Green Building Council (DGBC) method.
Note: Assessment method results are overlayed with normalised expert interview second round results utilising the proposed method formula.
Table 7
Normalised expert interview DPr correlations to disassembly potential (DP) assessment method results.
| METHOD | PEARSON CORRELATION | p-VALUE | SPEARMAN CORRELATION | p-VALUE |
|---|---|---|---|---|
| Proposed method versus expert interview results | 0.933 | 0.00003 | 0.866 | 0.00057 |
| Dutch Green Building Council (DGBC) method versus expert interview results | 0.658 | 0.02800 | 0.655 | 0.03400 |
Table 8
Comparison of dependent correlations (proposed versus the Dutch Green Building Council (DGBC) method).
| STATISTICAL TEST | z-VALUE | p-VALUE | 95% CI FOR DIFFERENCE |
|---|---|---|---|
| Steiger (1980) | 2.045 | 0.041 | n.a. |
| Meng et al. (1992) | 2.051 | 0.040 | [0.040, 1.742] |
| Zou (2007) | n.a. | n.a. | [0.013, 0.826] |
[i] Note: CI = confidence interval; n.a. = not available.
Figure 5
Bland & Altman (1986) analysis comparison results.
Note: For values, see Appendix 5 in the supplemental data online.
Figure 6
Mass (t) and relative DPMtotal (%) of the case study buildings evaluated with the proposed method.
Figure 7
Global warming potential (GWP) (kg CO2e/m2) and relative DPGWPtotal (%) of the case study buildings evaluated with the proposed method.