Replies

1. 
   BillHartmann | Jul 09, 2004 06:36pm | #1

   If this is a garage slab what "water" are you trying to keep off it other what drips off a car when it is raining.

   I have such construction with shop and office under it and never had any hint of water flow through. Just not enough water to cause a problem.

1. 
   user-995102 | Jul 09, 2004 07:18pm | #3

   Thats good news; I work in an architects office doing structure for them.  We view the potential cracks over living areas as problematic, naturally.

   good to know that 'normal' rain water dripping off the vehicles may not be a problem.  I just thought that there may be a relative easy way to solve this.  The two caveats of concrete are, it costs too much,and it cracks.

   A top of concrete application may crack with the normal concrete cracks.  As stated,other methods are problematic.

   Macco

1. 
   BillHartmann | Jul 11, 2004 05:21am | #6

   The July issue of The Jorunal of Light Construction has a big article on pouring a spended garage floor using the foam decking material (and also ICF foundation walls).

   If you can't find a copy you can buy the article for $5 online. Go http://www.jlconline.com Then Research and you can find the article by going to the July issue.

2. 
   user-995102 | Jul 09, 2004 07:20pm | #4

   Sorry; I should add that builders with this configuration have said that unheated garages set up condesation below, on the exposed steel.

   Thoughts?

1. 
   BillHartmann | Jul 09, 2004 07:47pm | #5

   I don't think that the unheated garage has anything to do with it. But unconditioned space below might.

   Now the only steel (outside of the rebar) in mine is an single I-beam support and post. I have had minor rust on plain nails that have been stored in their, but never any problems on my tools.

   But I live in an are that gets very humid in the summer and this is about 50% exposed (it is on a on a slope). But a basment has similar problems in this area.

   Mine was pour over plywood with temp supports using steel joist and wood post. That was 25 years ago.

   If I was going to build today I would very strongly look into one of the foam deck systems. When I setup part of it as office I figured that there was a big heat loss through the concrete ceiling and it was hard to insulate.

2. 
   gdavis62 | Jul 09, 2004 06:48pm | #2

   We did exactly what you are looking to do.  The plans specified the use of precast hollowcore planks, about 10" thick by 3'-4" wide, which will span the width of a garage and support cars easily.  A thin slab is poured atop, and then waterproofed using one of the two-part elastomeric deck coatings by Sonneborn or Sika.  The kind of construction used in some parking garages.

   These types of coatings go on with a notched squeegee, each coat, primer and finish, going on at 40 wet mils thickness.  We sprinkled granulated hard rubber on the finish before backrolling it, to create a slip-proof texture, but fine silica sand can be used, also.

   Since the shop below our garage is heated space, we chose instead to build using LiteDeck forms, which were used to create a concrete floor structure with integral reinforced beams on 2'-0" centers.  The forms are styrofoam, and require temporary shoring for the pour and cure.  But when stripped, there is a considerable amount of styrofoam in the ceiling to insulate, and the rollformed steel studs that are integrally molded into the LiteDeck forms permit direct attachment of gypboard, for finishing the ceiling and hanging lighting.

   Google for Lite Deck, and you will see more about it.