Glass Fiber (GF) membrane was modified using bis(diaryldiazomethane) derivatives with various terminal functionalities and characterized via multiple techniques including SEM, XPS, ATR-IR, proving successful modification and offering an alternative route to surface-modified glass materials. Significant changes in surface wetting were observed by successive functionalization of the GF surface. Surface modification was proposed to proceed through two independent mechanisms, the first being insertion via carbene into surface X-H (Si-O-H) bonds, while the second is polymerization by propagation of the carbene with active surface terminal amine functions; this is the first time that carbene-mediated polymerization at a modified surface has been identified. This latter process proceeds without catalysis by transition metals, and leads to encapsulation of the glass fibres. This approach is complementary to traditional silane coupling reagents, producing bis(diarylcarbene) (in short, biscarbene)-modified GF membrane in which surface physical and chemical properties have been modified independently of the bulk.