Concrete sawmill pad --- 14 x 4 x 6" --- what not to do

[DDW_OR]

great find on those dobie blocks
saved over $110

[jmouton]

hey jemclimber i was talking about wire mesh ,  if you put it in then it will be in the middle or so, and most wire mesh you buy is rusted so when you add water it rusts even more , and concrete is porous ,,so do the math ,  it does work good if placed right,,,,,fiber mesh on the other hand was big in the 90 s , has kinda went by the wayside,,,people still use it whether its fiber or metal,   not many in mich,  fiber mesh will crack more than with wire mesh in it ,, fiber mesh is more expensive ,

[kensfarm]

I did a slab off the back of the house..  26x21  I did the framing and hired a concrete finisher.  Got the 4000psi..  wire mesh..  and laid some rebar on top of the mesh around the sides and cellar stairwell..  I did 6in thick slab.  The finisher pulled up the mesh as it was being poured.  He offered to make cuts but I didn't want them.  6 years later.. no cracks.  The finisher had done concrete work for 30 years.. he only wanted $250.. but he stayed all day... directed the pour.. and did the finishing in 3 steps as it dried.  I gave him $300.. he knew what he was doing.
Also had the electric meter moved.   

 

As the project progressed.. old timbers from collapsed bank barn across the street.

 



 

[Weekend_Sawyer]

I have poured 2 slabs for sawmills. Never got around to building a roof over either of them.
What I learned.
Use grade stakes made out of steel to show the middle of the pad so you don't make the middle a                       low spot.

4" is pleanty thick. I dove my skid steer on both of them.

Use concrete reinforcing wire.

Do not trowel it into a mirror finish. Float it and then take a 2' wide broom and brush it. The first one I did had a nice slick finish on it. and when it got wet it was REAL slick!

Have it fall to one side, 1" over 8' is pleanty, this will help water shed off.

Neither of my pad's cracked but the ground they are on was well compacted by cars and trucks over the years driving over it.

That's all I can think of for now.
Jon

[OffGrid973]

Final Plan:
2x6 form surrounding the 4x14x6" thick with lots of stakes to support outside.  (reason=1.03 yards)
$150 for delivery
$125 for a yard of 4,500 lbs from a local place here in Bridgewater, NJ ( shortloadconcretellc )

Told me to call 2 days in advance and I am finalizing the forms this weekend. 
Going to dig down further and lay a little more rock so driveway is parallel to the 6" slab top when poured.

For anchoring the rails down to concrete do I actually want to place bolts into the concrete.   WEDGE ANCHORS? TAPCON? NOT NEEDED?
I am sort of afraid this will lead to more cracking by introducing weakness right off the start?

Anything else I missed?

Comments appreciated,
-Chris

[grouch]

Put in anchor bolts. Not hex-head bolts. Anchor bolts -- L-shaped. You're not weakening the concrete, else every pre-engineered steel building and a world of pole barns should collapse any second now.

Weekend_Sawyer has given you fair warning about a slick finish. My late father-in-law (roofer, carpenter, farmer) poured a porch and hand trowled it to as fine a finish as I've ever seen on concrete. Then he sealed it. After the first rain, he decided it needed a roof and some indoor-outdoor carpet.

[OffGrid973]

Lol...I found a local guy to float it for me after poured and put the rough finish with a broom.

Thanks again forum, pics should be up in the Next few days.

[OffGrid973]

Update: 2x8 are level going to keep em out along with gravel until pour day.



  

 

[Kingcha]

One thing i learn here.   You will want to raise your mill up off the concrete pad at least a foot or more.  You can make your own beams to do it if you want with some treated lumber on the bottom.    It will save your back.  I only went about 8" do to height of my mill roof.   I wish I had gone more.



 


 
Matt

[petefrom bearswamp]

My 2 cents
My slab was poured in 2000
Modified Alaska slab, 12' wide, 26 long.
Footers 12" deep below bottom of floor, 18" wide with 4 runs of re rod in them.
Main floor 6" 3000 pound mix with re mesh.
My climate is pretty darn cold and it has neither cracked or moved.
Maybe over engineered but well worth the effort.
Of course this was for an lt40 not a much lighter mill

[JD Picket]

I would only use fiber added to the concrete for what you have. Wire mesh is a pain and on all government regulated building sites the new standard is fiber and not mesh. I have a 30'x40' shop and the concrete only has fiber in it and I have no cracks but I also have joints cut every 10'. Fiber runs about $9 more per yard and you can't buy mesh for that price. As far as anchors I would use wedge anchors and don't mount the mill directly on top of the slab. It will rust the bottom of the frame at a faster rate then normal because of the chemicals in concrete. You will want rubber between the frame and concrete. Mills viberate and will bust out any anchors you put in the slab. Also the frame will expand and contract at a different rate than concrete. Hope this all makes sense. Just got off working nights.

[OffGrid973]

Makes perfect sense to me, and the vibration was my main concern causing cracks, etc.  Rubber is an interesting idea, just need to find the sweet spot so I don't cause waves in the rails based on where the logs are placed.

[grouch]

My assumption when recommending anchor bolts was that there would be wood or some other cushioning, forgiving material between concrete and mill frame. Bolting the mill directly to the concrete doesn't sound sound (Tom) to me. Bolting what amounts to sill plates (wooden) to the concrete and then building on them (e.g., see Kingcha's post above) lets you take advantage of the stability of the concrete while protecting it from the vibration, different rate of expansion and contraction between concrete and steel, and lets you put it at the height you choose.

[OffGrid973]

Oh man, who knew how heavy rock was. The slate under the dirt that had to be sledge hammered out was quite possibly the most ridiculous necessity I have come across in this project.  Looking forward to the pour on Tuesday morning.

How long should you let a new cement pour harden (days) until I throw the lt-10 and a 1,500 lbs log on there?

 

[Ljohnsaw]

Wait at least a week.  Also, keep the concrete wet after it gets hard.  It needs water to cure.

[Blaszer]

After you've finished the concrete, put burlap over the whole thing and wet it....and keep sprinklers on it to keep it wet.....This keeps it cool and allows it to cure uniformly and reduce chance of cracks....

[OffGrid973]

Thanks for the pointers guys, pour went great and setting up nicely.



  

  

 

[BigZ La]

After you've finished the concrete, put burlap over the whole thing and wet it....and keep sprinklers on it to keep it wet.....This keeps it cool and allows it to cure uniformly and reduce chance of cracks....

10 day cure makes it very hard.

[paul case]

I have never before seen a 1 ton truck mixer like that. Around here if you order 1/2 a yard or 100 it comes in a semi truck sized mixer.

PC

[Ljohnsaw]

Out here, you can get a cart (trailer) with tandem axles and a mixer on it that looks just like the drum on that truck.  It will hold a little over a yard, has a gas motor running a hydraulic pump.  The drum rotation and dump are hydraulic.

[47sawdust]

That is a nice redi-mix truck.Nothing like that here,same as Paul Case mentioned.

I'm surprised your allowed to set up your mill in that neighborhood.I would think the zoning regs. wouldn't permit it.Good luck to you,I'm sure you will get a lot of positive attention.

[thecfarm]

Now that's a cement truck. Smaller,lighter,go across a lawn with less damage too.

[petefrom bearswamp]

Your pad looks good.
I  second the opinion of rubber between the mill and concrete.
I use old pieces of truck bed mat.
I sometimes load big logs on the mill directly with my tractor and the mill still moves somewhat.
If it was steel to concrete I think there would be much more movement as well as vibration stress..

[ChugiakTinkerer]

Old conveyor belt material would work good too.  Would love to get my hands on some but it's like hen's teeth up here.  I do love that cement truck, the right tool for the job.