<p>To minimize greenhouse gas emissions, the development of biobased building materials is gaining increasing priority. Wood’s insulation performance can be enhanced by creating additional porosity through the removal of non-cellulosic substances. Although delignification techniques have been used in the pulping industry to produce cellulose pulp, they have evolved to produce cellulose nanofibers or cellulose scaffolds for functional materials. Various top-down delignification techniques have been suggested for solid wood, but most studies have focused on a single technique applied to a specific wood species, making it difficult to compare the effectiveness of different methods. This paper addresses this gap by presenting a comparative analysis of literature-established delignification techniques applied to solid wood pieces: soda pulping, alkaline sulfite pulping followed by hydrogen peroxide bleaching, and organosolv pulping followed by sodium chlorite bleaching. This study evaluated the impact of these techniques by examining the changes in mass loss, chemical constituents and FTIR spectra of French poplar wood planks of 100 cm³ after treatment. The combination of organosolv pulping by alcoholysis and sodium chlorite bleaching was found to be the most effective method for complete lignin removal. Our findings reveal the strengths and limitations of these methods, providing insights into the selection of wood modification techniques for upscaling purposes. Further research on drying delignified wood is required to complete a preliminary study of the industrialization of insulating wood. These advancements promoted the sustainable use of wood as a mechanically strong thermal insulator to reduce building energy consumption and mitigate climate change.</p>