## 5 Results
Considering the huge existing building heritage, which has not been designed for deconstruction, it is clear that these layers are the most difficult to deconstruct and that demolition often appears to be the fastest and most obvious choice. In the case of deconstructable buildings, namely buildings that have been designed to be completely deconstructed at their end of life, the structural deconstruction must take place from top to bottom--therefore from the roof to the foundations, so as to operate safely and avoid collapses of the structure. Once the building layers have been defined, it may be easier to consider deconstruction and resource reduction strategies during the design process. However, it is also necessary to analyze the differences that arise between the various construction systems to evaluate the degree of deconstruction effect that a building can have. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Criteria** & **Demolition** & **Non-Structural Deconstruction** & **Structural Deconstruction** \\ \hline \multirow{3}{*}{Definition} & Arbitrary destruction of building & Removal of building components & Removal of building components \\  & in order to quickly clear the & not affecting the structural & completely integrated in the \\  & construction site & integrity of the building & building and with structural \\ \hline Time & Few days & Few days & Days or weeks \\ \hline Costs & Low & Medium & High \\ \hline \multirow{3}{*}{Equipment} & Expertise required for cranes, & Simple tools required. Special & High range of tools and \\  & excavators, and wrecking balls & expertise is usually not required & equipment required. Special \\  & & & expertise could be required \\ \hline Safety conditions & High & Standard & High \\ \hline \multirow{3}{*}{Degree of deconstructiveness} & \multirow{3}{*}{None} & High & Variable \\ \cline{1-1} \cline{3-3}  & & & \\ \cline{1-1} \cline{3-3}  & & & \\ \cline{1-1} \cline{3-3}  & & & \\ \cline{1-1} \cline{3-3}  & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Comparison between deconstruction and demolition. Regarding load-bearing walls in buildings, most of these are made with bricks connected by wet binders such as mortar, lime, or cement. The use of binders to keep the building components united is an obvious obstacle to the deconstruction process, as it can lead to component breakage and the subsequent impossibility to reuse them [47], so they are more likely to end up in a landfill. A possible option to close the loop is recycling: bricks can be used as a secondary raw material after being shredded and employed in various construction activities, for example, for roadbeds [47], in a process of downcycling, as they lose some properties and quality in their second life [82]. However, the best option would be the reuse: load-bearing walls can be dismantled in bricks, and after the binder is removed, the bricks can be reused. However, dismantling a brick wall might increase the need for safety precautions, and removing the mortar can be difficult and time consuming. Attempts can be done to keep the value of the products and upcycle them into new building products, such as new bricks and tiles, but this would not necessarily be economically feasible, involving bricks cleaning and smoothing treatments [47], and in many cases, these bricks cannot be reused as structural elements [12]. To avoid this situation, bricks can already be designed to be easily disassembled and reused. A good example for such a design is the dry-stack bricks [83]. A load-bearing wall made by dry-stack bricks consists of clay or concrete interlocking blocks that are laid dry-stacked or with minimum mortar slurry in a stretcher bond in a wall. Sometimes, the binder to join the bricks is replaced by plastic or metal units, with the same result to make the bricks easy to separate and reuse.