Lekkie przegrodki to partitions. Nie uzylabym slowa "light" poniewaz w kontekscie budowniczym kojarzy sie ono z oswietleniem, a "partitions" juz sugeruje ze sa to LEKKIE przegrodki (a nie "walls").

Przyklady:

... make it an ideal product for the accomplishment of interior partitions, exterior glazing of all types, intermediate insulation of lofts, and false ceilings for ...
www.buildingonline.com/sgi/modular.htm

... and install eave fillers, which serve the same function as corner blocks. Then attach glazing partitions and glazing tape as you did for the front panels. ...
www.hgtv.com/HGTV/project/0,1158,BDRE_project_20888,FF.html

Ullrich Aluminium (Extruded Products): Partitions (INDEX)
... INDEX - Partitions. Partitions Page One Partitions, Glazing Bead, Die Insert. Partitions Page Two Partitions. ...
ullrich-aluminium.co.nz/partiton.htm