referring now to fig1 - 3 , there is illustrated a number of heat shearable pedestals 12 that are mounted on an existing floor in vertical columns , such as column 15 , and horizontal rows such as row 16 . the existing floor , herein referred to as a substructure 18 , is irregular and slopes in one or more directions towards drains for carrying away rain water or the like . this causes special problems when attempting to lay a level deck over the substructure . as illustrated in fig1 , a specially constructed leveling apparatus , generally referenced 20 is employed to rapidly and efficiently shear the upper part of each pedestal so that the top surfaces of the pedestals all lie in a common horizontally level plane . as described in the previous referenced 5 , 363 , 614 patent , the disclosure of which is herein incorporated by reference , the pedestals are formed of a high density foam , such as polystyrene , and are secured to the substructure using an appropriate polystyrene compatible adhesive . the height of the pedestals are such that each extends upward to a height greater than the desired elevation of the deck . initially , the first column in the pattern is leveled or aligned within the desired horizontal plane . this is achieved by placing a pair of spaced apart tracks 22 — 22 on either side of the pedestals in this first column . a connector plate 23 ties at least one end of the two rails together as shown in fig1 and the two ends of the rails are supported on cross members 25 . each cross member , in turn , is supported upon adjustable leveling legs 27 — 27 . using the adjustable leveling legs and a laser gun , the rails can be brought to a desired horizontally level position on either side of the column . a cutting carriage 30 , as shown in fig3 , is mounted between the tracks so that it can move freely over the pedestals in the column . the carriage contains a heatable cutting wire 32 which is horizontally disposed beneath the carriage between two support arms 33 — 33 . the wire is stretched tightly in a straight horizontal line between the arms and is connected to a suitable source of electrical power ( not shown ) by electrical lead 35 for heating the wire to a temperature suitable for shearing the tops of the pedestals . in practice , a direct current of between 2 and 50 amps is used to heat a 0 . 02 ″ to 0 . 05 ″ stainless steel wire to about 1200 ° f ., which is the preferred shearing temperature for polystyrene . once the wire is heated to the desired shearing temperature , the carriage is moved manually along the tracks so that each pedestal in the column is cut to the same horizontally aligned elevation . after a first column of pedestals has been sheared , a second column of pedestals spaced some distance from the first is then sheared and grade supports 40 — 40 are seated upon pedestals in the two sheared columns , as shown in fig2 . the tracks are now turned 90 ° and seated upon the grade supports on either side of a column that contains unsheared pedestals and the carriage is moved over the column to shear all the pedestals in the column to the desired level . the tracks are similarly repositioned with regard to the other unsheared rows until all the pedestals are cut level within a common horizontal plane . turning now to fig4 - 6 , a series of rectangular grate panels 50 are mounted so that the four corners of each panel rests upon the top surface of four pedestals that reside in adjacent rows and columns . the pedestals are spaced apart in the rows and columns on equal centers so that the corners of the panels come together at the center of the pedestals to establish a subfloor . the pedestals in the outermost rows and columns may be cut along the center axis of the row or column so that the edges of the edge pedestals 53 ( fig4 ) are parallely aligned with the outer edges of the overlying panels . in this way , the panels can be brought in close alignment with the sidewalls of a terrace or balcony that form the perimeter of the substructure . preferably , the panels are placed in edge to edge contact upon the pedestals or alternatively , a cruciform joint divider can be used to help space and align the grate panels in assembly . the grate panels can be made of any suitable material such as steel , aluminum , plastic or fiberglass , depending upon the specific deck application and its intended load carrying capability . each grate panel contains a series of perforations 52 — 52 that pass downwardly through the top and bottom surfaces of the panels which reduce the weight of the panels without substantially reducing the load carrying capacity of the system . although the perforations are shown as being square shaped and parallely aligned , the perforations can be almost any shape and can be placed in any suitable pattern which will not adversely effect the panel &# 39 ; s load carrying capacity . a series of small interlocking paving blocks 55 — 55 are laid down upon the top surfaces of the panel in an interlocking pattern to complete the deck upper floor 60 . as noted above , the interlocking block are about the same size as a standard brick and can be laid down in an interlocking pattern as shown in fig4 and 5 to provide a very tight , but decorative deck that is relatively impervious to weather and capable of handling a good deal of traffic without showing appreciable wear . the term interlocking , as herein used , refers to a block pattern wherein the joints between the blocks do not coact to create long seam lines . the seam lines of the interlocking blocks are relatively short and dead end at a side wall of another adjacent block as shown in fig4 and 5 . once in place , the interlocked blocks form a tight pattern that resists lateral movement in all directions . a sheet 57 of geotextile material may be laid on top of the panel network to protect the panel from the paving block , particularly in areas where the deck loading will be relatively high . the sheets of geotextile material will also serve to deaden unwanted noise that might be created by the pavers rubbing against the grates . lastly , the perforations formed in the grates are relatively small in comparison to the surface area of the pavers so that the pavers can be well seated upon the top of the panels with little or no relative movement therebetween . while the present invention has been particularly shown and described with reference to the preferred mode as illustrated in the drawing , it will be understood by one skilled in the art that various changes in detail may be effected therein without departing from the spirit and scope of the invention as defined by the claims .