vectortech

i use model set up for a 2 story house.i like this system. when i view all layers (after -align layers-),the house is displayed correctly (all layers stacked and touching-correct z values.i create a new layer (active) for a layer link,then choose the appropriate layers. when the link appears there are spaces (usually the delya z value) between the layers. i have double checked delta z and z value entries. what can i do to get the link to display correctly? thanks