Expert: Bruce E. Johnson - 8/21/2009

Question
Bruce, can you tell me the advantages or disadvantages of building apartments on slabs. And the same for crawl spaces

Answer
Hi Terry, commercial monolithic slabs are more cost effective than foundations with floor systems or stem walls with slabs on grade.   With a crawl space you need to pour a footing, build up a masonry or concrete wall, bring in the trades, build your floor system have the trades do their penetrations, insulate, install your sub-floor and then you are ready to build your building. Then you have to deal with maintaining the crawl space against bugs, moisture, critters, fire, etc..  With a monolithic slab you set up perimeter boards, dig your footings, have the trades install their piping etc., then it is just a matter of pouring the slab.  Bingo you are ready for walls.  You can sequence your buildings better with mono slabs, a concrete contractor can run perimeter forms in one day usually.  This allows your trades to get into the ground faster.  As they move on to the next slab you pretreat the soil one time for termites, your concrete guy follows up with the pour.  You do have to keep a closer eye on the electrical subs and plumbing subs with a mono slab to make sure their stuff is in the right place prior to the concrete going down.  You also need to keep an eye on the concrete finishers so that piping etc. is not dislodged during the pour. You will find that you can probably cut a week or two off your construction schedule per building with a monolithic slab.  I hope this information helps please feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com