the length of the abutment surface measured between outer and inner faces should be adequate to permit the interengaging means to be dimensioned for acceptable strength because of the special construction of the dome of the present invention involving the insertive engagement of a plurality of panels the last panel to be laid in place namely top panel a 1 shown in fig1 requires a non insertive means for interengaging with the other panels this is accomplished by modifying one of the isosceles panels a such that instead of the receiving groove on two edges thereof said edges are rabbetted as shown in fig1 to facilitate the 34 drop in 34 assembly shown in fig1 thereby completing the domical enclosure although the panels described hereinabove provide a self supporting structure by virtue of their novel interfitting characteristics bonding agents may be applied to the joints between panels during or after assembly of the dome structure said bonding agents may be in the nature of sealants caulks or adhesives which promote interbonding of the panels and seal any openings through which water may pass such bonding agents are flowable compositions which will harden and adhere to said panels exemplary bonding agents include silicones polysulfides polybutenes and other resinous materials which may be applied as solvent based or hot melt compositions and solutions containing polymeric material from which said panels may be fabricated the panels of the present invention are preferably fabricated from polymeric materials by.