Replies

1. 
   Mad_Dog | Sep 26, 1999 08:21pm | #1

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   It depends on where you want your concrete to crack and if
   you want to control it.

1. 
   PRP | Sep 26, 1999 08:31pm | #2

   *First, if the slab is large enough then maybe 'Yes'Second, if you don't want random cracking and it is large enough, then definitely.

2. 
   Guest_ | Sep 27, 1999 07:42am | #3

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   Has anyone ever seen a slab without crack control lines that hasn't craked ?

1. 
   Guest_ | Sep 27, 1999 08:17am | #4

   *You mean you can control crack heads with lines on concrete? - jb

1. 
   Guest_ | Sep 27, 1999 05:17pm | #5

   *Marc, All concrete will crack;with expansion and contractionif not from differential settling of subgrade. Properly placed joints(off corners,thru/in line w/penetrations,and across the slab e.w. to limit the size of a section to 200 sq.ft.) will give you the best chance. Penetration of joint needs to be 1/4 depth of slab. Having gone to these lengths and beyond on many occasions, errant cracks still have run in the "wrong" direction. In a residential basement slab ,I feel that this is an asthetic consideration for the benefit of the homeowner, many of which are concerned upon seeing any cracks, that the slabhas failed and will argue to replace it or get a "rebate".Curiously, they never complain about the cracks at the bottom of the joints due to the fact that they less noticable. In a basement slab bounded by perimeter walls, where is the slab going to go? You have an option to use a product known as "zip strip"which is a thin plastic band(1 1/4"x 1/16") serving the same structural purpose as a tooled joint. Installed in wet slab duing the pour , a basic pain plus a liklely conflict with tubing Given your application with tubing and hopefully rebar,any cracking would be minimal in width (hairline). If you pour directly on the eps there exists a strong liklihood of creating "craze" or "alligator" cracking on thesurface of the slab, a potentially larger problem of scaling activity. I trust that your conrete guy offers a warranty beyond "fire and theft". Grins, Rick

3. 
   Marc_Sillars | Sep 27, 1999 05:27pm | #6

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   My structural eng suggested that I cut crack control lines in my new basement concrete slab being poured. I have never heard of this in the basement slab only exterior slabs. What do you think.