I've tried to find a forum or a site that might answer my 'engineering' question, to no avail, so I figured I might check out the brains here. I've got several dozen boulders, some good for nothing but landscaping, but quite a few huge (~6' x 8') flat boulders that I want to incorporate in a portion of the floor in my new home. Basically huge flagstones. I know how to lay flagstone, but these are around 6 to 8" thick. A straight slab won't work, as they'd stand up very high, and the baby flagstones would have to have a six to seven inch bed of mud to level the floor out, so that's unreasonable. Easiest solution would place the boulders in place, blocked off the ground, with all the vapor barrier and steel in place ready for the concrete truck. My only concern is getting the concrete completely worked under the rock, and keeping the rock in the right 'attitude'. Shifting during the pour or cure would mean a huge chunk of trouble. Another solution is to map out the boulders position in the slab. Make indented slots for the boulders (widths x depth +wiggle room). Finish and cure the slab. Then set the boulders into their matched holes, mortar and grout, combined with the other flagstones, or slate, and be done with it. Concern with this process is moving the boulders over the cured slab. Would hate to crack the slab. Neighbor has a huge crane that is available, that'd easily move the rocks (and beams later), but he's going to sell the crane, more than likely before this project begins. The rock is free. Currently within 20' of where I'll need it, either in floors or walls or landscaping. I saved them from getting covered by 30' of water when my pond was dug. My dozerman's eyes got big one morning when he showed up for work...a handful (bad pun?) of the boulders were parked up on the hill next to his dozer...he looked at em and wondered how they got up there...Noticed after that day he'd push the larger VW sized ones out...and I'd get all the minor yugo sized ones out after he was gone...and after I'd put in three or four hours digging with his D6. Any critiques, advice, websites, etc. would be appreciated. I know stone is cold. I hope it IS cold in the summer. In the winter, free natural gas tends to neutralize the coldness. BTW, I know I don't '''need''' rocks that large. This home is not about needs. I've got my '''needs''' home already. This is my 'wants' home. I was hoping to make it onto HGTV's Extreme Homes, but alas, it appears the series is in hiatus, or has been cancelled.