Abstract: A modular wall panel assembly comprising a plurality of generally rectangular shaped elongated horizontal slabs. Each slab has a series of vertical through-going apertures, a sloping outwardly front surface and a vertical rear surface. A plurality of wallboards are provided with each wallboard secured to the rear surface of each slab. Each wallboard will overhang a bottom end and a rear end of each slab and will be set back from a top end and a front end of each slab. A plurality of siding sheets are also provided, with each siding sheet secured to the front surface of each slab. Each siding sheet will overhang the bottom end and the rear end of each slab and will be set back from the front end of each slab. The slabs can be interconnected one upon the other and side by side, with the through-going apertures in the slabs above in alignment with the through-going apertures in the slabs below. The wallboards abut each other and the siding sheets overlap each other.