Method of producing a heavy modular unit and a modular unit produced according to the method

A method of forming, at a building site, a stable and, in terms of weight, heavy modular unit that can be adapted to serve as a complete modular-built cellar unit, the method comprising the steps of:

• transporting to the building site a prefabricated and, in terms of weight, considerably lighter complete modular unit previously formed at a production site different from the building site, said lighter modular unit including:
• a base slab having length and width dimensions corresponding to those of a cellar,
• a plurality of double-walled wall sections formed from flexurally rigid cement fiber panels and anchored to the base slab, the plurality of double-walled wall sections including a number of inner wall portions facing in towards the modular unit and a number of outer wall portions facing from the modular unit, said inner and outer wall portions being mutually coordinated,
• a plurality of supports securing said inner and outer wall portions together, the plurality of supports being located within a free space formed between the inner and outer wall portions, and dimensionally defined by said inner and outer wall portions secured to one another via said supports, and
• one or more modular unit-allocated interior design details mounted within the double-walled wall sections,
• at the building site, filling the free space with a concrete mass which is caused to cure or set to form, in terms of weight, in combination with the lighter modular unit., the heavy modular unit,
• the inner wall portions having such dimensions and mechanical strength-related properties that these inner wall portions, in combination with only said supports, support selected ones of the modular unit-allocated interior design details, which are fixed to selected wall sections of the inner wall portions, and form a first form side of said free space that is able to withstand the pressure forces occurring upon concrete pouring into said free space, and
• said outer wall portions having such dimensions and mechanical strength-related properties that these outer wall portions, in combination with only said supports, form a second opposing form side of said free space that is able to withstand the pressure forces occurring upon concrete pouring into said free space.