If you have a honey flow and not enough bees they bees will backfill the brood chamber rather than build new comb. The way to cure that is to leapfrog the outside storage frames away from the brood area to force the bees to build comb.
Can you explain that again....?
I'll try to clear the muddy waters.
1st bees only build comb under foot so if there are not enough bees to occupy all the frames in a box they will only draw comb on the frames they are congregating on. Once the comb building has caught up to the number of bees, so all bees are standing on comb, they will stop building comb and begin to backfill the already drawn comb not occupied by brood. They will will also backfill the cells as the brood hatches if they can beat the queen to the cell with nectar.
Once the population of the hive has risen to the point that bees are crowed off the comb frames onto new frames they will again begin to build comb on the additional frames now accupied by the bees.
Almost always, the outside frames on each side of the box are honey storage frames while the rest of the frames might be used for brood rearing in the boxes that comprise the brood chamber.
Now for leapfrogging the frames: Let's say that you have 6 frames of bees, on comb, and 4 empty frames, 2 on each side of the drawn frames next to the box's walls. Of the 6 frames of drawn comb the outside drawn frame on each side of the core or cluster is honey stores, or at least the outer side of the comb is, the inner side might contain brood, but that is really immaterial to out discussion. The important point is that by moving the storage frames the drawn, often capped frame of comb, is moved away from the core or cluster and an empty frame is inserted. The bees will then move off the storage frames, as stored honey needs no attendence, and will occupy the empty frames. This will then cause the bees to draw comb on the new empty frames they've been forced to occupy.
To illustrate our discussion, a hive that has empty (E) and occupied (0) frames thusly; E E 0 0 0 0 0 0 E E will be changed to look like this; E 0 E 0 0 0 0 E 0 E and will begin to look like this within a day or 2: E S O O O O O O S E where (S) represents the vacated honey storage frames.
I hope this explanation is more comprehensive.