Cement experts Help

[minthral]

First thing to consider is where your footings are and what size and how deep. Next is considering grade and compaction. You dont want to put concrete on top of disturbed soil as it will settle over time. You want the base soil to be as hard as possible which is normally below topsoil…varies by location but by 2-3 feet it’s better, however a slab doesn’t need footing grade soil as it’s large and spread over large area. You want 4+ inches of washed gravel (3/8 or larger) for drainage then compact it. Put 10mil plastic and then foam board on top. Then pour 4+ inches of fiber reinforced concrete 4-5k PSI. Last hydrate the concrete once or twice daily.

I’d say hire a pro to do it, but chances are the contractor will know less than you.

 

[top gnome]

He is in Nova Scotia and the winters are extremely cold. He needs to excavate down at least 3 feet and remove all the rocks, otherwise, the frost will heave those rocks upward and it will crack his cement slab. Before I paved my driveway we excavated down 24" and removed every boulder and rock. Now, 30 years later, we have boulders coming up in the driveway that is causing major expense to dig them out, fill the holes with compacted gravel, and then pave the repair. This has been going on for over 20 years. Right now, there are at least 3 that need to be removed, but with the high cost of asphalt, it just isn't in the cards. My wife keeps bringing the subject up, and I keep telling her that I will leave it for the next owner.

We do get -10F at least a week or two a year. Here is what is required for the actual concrete . if I thought I could keep the mice out I would build a smaller pole building that did not require a permit.I I have a neighbor with a sawmill and he has cut up my storm uprooted and broken trees so I have over 600 bd ft of rough saw lumber and he charges less than half of what the lumber yard charges but the code says graded lumber only,

 

[top gnome]

First thing to consider is where your footings are and what size and how deep. Next is considering grade and compaction. You dont want to put concrete on top of disturbed soil as it will settle over time. You want the base soil to be as hard as possible which is normally below topsoil…varies by location but by 2-3 feet it’s better, however a slab doesn’t need footing grade soil as it’s large and spread over large area. You want 4+ inches of washed gravel (3/8 or larger) for drainage then compact it. Put 10mil plastic and then foam board on top. Then pour 4+ inches of fiber reinforced concrete 4-5k PSI. Last hydrate the concrete once or twice daily.

I’d say hire a pro to do it, but chances are the contractor will know less than you.

thank you great information. My intention was to hire a pro to install the slab but prep the ground so they can come in and put the forms up and pour. right now I am laying in 4 to 8" rock to get to level and then class a gravel on top of that I am removing the loose rock. than you again

 

[North Idaho Wolfman]

This was done yesterday.
16" footers, 12" wide base, 2 parameter rebar, wire mesh center, with vapor barrier, on crushed stone.
1/4 of the right rear is sitting on solid granite!

 

[North Idaho Wolfman]

A few of the House Mono, 24" deep, 12" wide at the base, 5" deep house, 7" deep garage.
Nary a stone to be had on this, 99% Sand.

 

[D2Cat]

Maybe those pictures of your house project show why time constraint on this forum is necessary? Looks like a lot of work and these days helpers are not to be found!

 

[North Idaho Wolfman]

Maybe those pictures of your house project show why time constraint on this forum is necessary? Looks like a lot of work and these days helpers are not to be found!

Yea the first pic is a pole barn that couldn't be a pole barn because of the granite.
Costing the customer another 10K just for the pad.

And Yes getting help is near to impossible and super expensive, laborers want $25+.

The second 4 pics are my house, but we are way past that now (thank goodness), still not finished, but we moved into it in November, it's really nice!

 

[GreensvilleJay]

Up here they just drill and epoxy into the granite of the Canadian Shield. Common practice for timber frame structures.

 

[top gnome]

Yea the first pic is a pole barn that couldn't be a pole barn because of the granite.
Costing the customer another 10K just for the pad.

And Yes getting help is near to impossible and super expensive, laborers want $25
The second 4 pics are my house, but we are way past that now (thank goodness), still not finished, but we moved into it in November, it's really nice!

we moved into our house in 2013 and added an addition and it still is not finished so your doing great IMHO

 

[top gnome]

Up here they just drill and epoxy into the granite of the Canadian Shield. Common practice for timber frame structures.

The Canadian shield is not moving anywhere.

 

[GreensvilleJay]

guess you consider it 'rock stable " ?

 

[Henro]

we moved into our house in 2013 and added an addition and it still is not finished so your doing great IMHO

Agree. We moved into our self built house around 1985. It was a five year project! Still not finished and never will be...LOL

 

[jimh406]

What are you calling a shed?

Large stones have more voids but don't pack. It depends on the type of soil and drainage you have in the area and the depth of each layer what would be best. In general, it makes sense to do what is typical for your area.

Do you for sure want concrete? Gravel with fines can be very smooth and of course, easier to do and less costly. The transition from the driveway if gravel can also be easier.

 

[top gnome]

What are you calling a shed?

Large stones have more voids but don't pack. It depends on the type of soil and drainage you have in the area and the depth of each layer what would be best. In general, it makes sense to do what is typical for your area.

Do you for sure want concrete? Gravel with fines can be very smooth and of course, easier to do and less costly. The transition from the driveway if gravel can also be easier.

I was originally building a pole barn but the inspector said for setting post I would need an engineer to approve a plan. Since there are no train stations around I am at a loss But the cost of the building itself is the same and expensive 14500 without tax or labor just materials so I guess the value of a garage vs a pole barn if we were ever to sell the cost of the slab would be covered. The other advantage is putting the backhoe and grapple on casters and being able to roll them around and out of the way. I think they will want concrete piers so the delta will only be a couple of thousand.

I am going to remove the large rocks and already have most of the tree roots pulled out. At this point i am going to use the backhoe and skim off a couple of feet then use 6-8 inch rock to level. then add 6-8 inches of class A then let the concrete guys take it from there. they are going to come out and have a look at some point but I am now pushed back on the slab until late summer.