Replies

1. 
   jet | Aug 23, 2002 04:54am | #1

   Did something similar here in Montreal Canada. My walkway is about 3 Feet wide and about 15 feet long. In the end I poured it between 8 and 12" thick. No tie in to the garage just floated it beside the wall. Has been there for 3 years now with freezing and thawing and no cracks or shifting yet.    I did put rebar into the pour.

2. 
   goldhiller | Aug 23, 2002 07:09am | #2

   I'd isolate the sidewalk from the garage foundation. If the garage has a frost free foundation, the garage wouldn't heave with the freeze, but the sidewalk would. If the two are tied together, this equals problems. Even if the garage doesn't have a frost free foundation, they will likely move at different rates. Again, problems. Keep them separated. When we pour sidewalks, we install re-rod and put fiber in the mix. Belt and suspenders. 6" pours. Keep your control joints frequent enough as to be functional.

1. 
   Shoeman | Aug 23, 2002 12:17pm | #3

   Thanks for the input, I was thinking isolated slab would be best but have not done this type of work before and am always open to suggestions.  Suprised to hear the thicknesses you guys are pouring.  Most people I had talked to said they would pour about 3-4" with mesh.

   Any more input on prep.  Pour right on undisturbed soil.  Compacted gravel (how much), compacted sand (how much), plastic in bottom of form? really open to any input I can get 

   thanks again,

   Shoeman

1. 
   Shoeman | Aug 27, 2002 05:16am | #4

   That's it? no more sidewalk suggestions? 

   Think I will go with a four inch thick slab, air entrainment concrete, mesh in slab, poured over say 6 inches of compacted gravel, isolated from the garage slab, with about 3 percent slope away from the garage, control joints every four feet, broomed finish, cover with plastic for a week or so

   gotta get this thing in...........any more suggestions or corrections?

   Thanks in advance to anyone who responds,

   Shoe

1. 
   Davo304 | Aug 27, 2002 05:38am | #5

   Hey Shoe,

   Whadda ya need us for?  You got it right.  Isolate the slab, use compacted gravel (2 to 4 inches thick), lay down some plastic, or simply wet down your gravel bed real good to prevent too much moisture from wicking out of the bottom of your pour. Then, install either a mat of rebar, or simply use the wire mesh ( which works just fine for sidewalks). Pour your sidewalk 4 inches thick (common 2X4s work just fine for formboards), cut in your control joints every 4 ft just like you planned.

   Everything you mentioned that you planned on doing sounded just right to me; including using the air entrainment; which is especially good to use on sidewalks or slabs that are in a snow region. You got it it right Shoe...now just go and do it!!

   LOL.

   Davo

2. 
   Davo304 | Aug 27, 2002 05:49am | #6

   OK,

   Here's the only thing I will add...instead of covering with plastic for a week, ask your concrete supplier where you can get your hands on some curing agent. This is a liquid that you can spray on using a garden sprayer. The liquid acts as a cover that helps the slab cure slowly without  it losing too much water too quickly.  I've used Thompson Water Sealer in the past, but I know there are commercial grade sealers that work a lot better.  Usually with sidewalks, you can actually walk on the thing the next day.  No way I would keep them covered for a week, but it would'nt hurt. Usually 2 days is about all anyone ever leaves them covered. By spraying on a curing agent, you don't need the plastic.

   Again, LOL.

   Remeber not to finish trowel until after the "bleed water" has first evaporated. Troweling too soon causes the top layer to spall...you don't want that.

   Davo

1. 
   Shoeman | Aug 27, 2002 03:43pm | #7

   Thanks for the posts Davo.  I will look for the spray to avoid leaving things covered.  Also thanks for the input about the plastic in the bottom of the form - that is another thing I was looking to get more input on when I posted.

   Thanks again,

   Shoe

2. 
   ScottMatson | Aug 28, 2002 01:39am | #8

   I'm agreeing with Davo about you having it right. We don't cover sidewalks or patios, etc. but it is certainly a fine idea, it will help more than hurt unless the plastic sags into the concrete...but then you probably wouldn't put it down over WET concrete would you?

   Fibered cement is a fine idea as well, but not necessary. Mesh is plenty good. A lot of new construction around here (Wisconsin) has big slabs being poured without mesh or rebar--and a lot of garages poured over uncompacted, unjetted sand. Just poured as is. I wouldn't recommend that, but the point is for a simple sidewalk, you've got it WAY covered doing it your way.

   Continually amazed at the way new houses are built,

   MD

3. 
   Shoeman | Aug 29, 2002 01:55pm | #9

   Thanks for input MD, feel confident to start now, just need the time to do so.

4. 
   JOHNTMAC | Aug 30, 2002 10:33am | #11

   I would advise against placing plastic on top of gravel base.  Water pooling under slab could cause curling of slab.  Also, we always use a rebar mat of at least  #3 bar on 18" centers.  Slab will remain intact long after slab with only mesh or wire matt.

3. 
   oldlou | Aug 30, 2002 04:22am | #10

   One small item that I have not seen here. Use 3500 lb strength concrete. This mix will tolerate the weather and deicing chemicals used in the very sub-tropic cities. better hurry, the 4th of July is long past and winter is overdue. My wife is from ND and I have her tell me winter stories during heat waves, cools me right off