Egon
Epic Contributor
Pretty easy to add Portland to premix in the mixer.
Premixed should have the proper aggregate grading.
Premixed should have the proper aggregate grading.
Concrete foundation without a cement truck
- Thread starter Little_Grizzly
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LD1
Epic Contributor
Yes, but it still cost more, and I still feel the aggregate is too small. Pea gravel aggregate in a 8" thick foundation is not ideal.
That premix stuff has small aggregate because it is used for setting posts, hobby projects like pavers, and 3" thick sidewalks.
Egon
Epic Contributor
What's wrong with the aggravate if it's graded properly? The real question would be the strength of the rock in the aggregate. For the situation and amount of work involved the price differential may not be too great.ok
It may also be possible to get premix in different strength's.
It may also be possible to get premix in different strength's.
EddieWalker
Epic Contributor
Most of the comments cover all your options for pouring concrete. Do you have a good supply of water for mixing? A hose is a lot nicer then buckets.
Just to change it up a little, you could also do a pole barn type building and make the floor similar to a deck without having to create any concrete footings.
Just to change it up a little, you could also do a pole barn type building and make the floor similar to a deck without having to create any concrete footings.
LD1
Epic Contributor
Not talking about the grading of the aggregate, talking about the maximum coarse size. As well as gravel vs limestone.
There is a whole lot of science and testing that goes into all of it in which I dont fully understand and aint going to go into. But in a nutshell, larger aggregate makes stronger concrete. Less shrinkage and less water to cement ratio are a few of the reasons.
Same with limestone vs gravel. Limestone used for coarse aggregate in the concrete makes the concrete stronger than if it were made with gravel.
So basically, the stuff premixed in the bag with small pea gravel for the coarse aggregate, is about the weakest concrete you can make. Sure, there are alot of other factors. You can make it stronger by using mimimal water to get it properly mixed, add a little portland, etc. But if you were mixing by had using raw ingredients, the little 3/8" pea gravel for the coarse aggregate, is the WORST possible choice you can make, and thats what comes in the bags.
Why that is whats in the bags....because it finishes nicely with smaller aggregate, flows into and around posts nicely whereas larger aggregate tends to hang up, and when doing thin (in comparison) sidewalks or stepping stones, it finishes nicely and strength is of little concern.
For a 8" x 16" footer, sure it will probably work just fine especially since footers typically get rebar laid in.
But if the OP has access to stone and sand, and a truck or dump trailer than can haul it, its a CHEAPER and BETTER/STRONGER alternative.
Either way, weather buying raw material or buying premixed bags, the OP STILL has to figure a way to get ~16000# to site. Thats still likely several trips. So weather they are all trips hauling premixed bags, or split up with some trips of sand, some of stone, and some of portland...its still alot of trips.
not2old
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I assisted several foundations in the mid sixties that were mixed on site. 1000 square foot house, at least 8 foot walls at the rear and most of the sides of the basement. Two or more hand mixers,8 men or more. Navy-jack gravel was dumped on site and plenty of bags of portland piled on site. We had water from next door and filled barrels to fill buckets. Start in one corner and work both ways, taking turns mixing, packing portland, tapping forms, moving gangways, having a break/eating etc. Took all day. Wouldn't want to work that hard at my age now.
Snobdds
Elite Member
You guys are stressing too much about concrete. We have a local block company that will produce any type of PSI rating you want. We went for a 6,000 psi mix. They mix up all the aggregate and bag it, but before they seal it they put in another sealed bag with the portland in it. That way you don't have to dry store it. They don't skimp on the Portland either, it was about 4lbs of Portland for every 80lb bag of aggregate.
If you don't have a block company that will do that, just buy these...
If you don't have a block company that will do that, just buy these...
OP
Little_Grizzly
Silver Member
Wow! I had no idea my simple question would blow up like this. I see some common threads in the suggestions:
1: Is there water available? If you would have asked last year (California drought) I would have said heck no. This year....yeah no problems. To be honest we even had steady water during the drought. On the topo maps our property is listed as "Water Gulch" :thumbsup: Side story: My great uncle homesteaded this property. He picked it because it's where you would always find the cattle at the end of the season. There was water, shade and an afternoon breeze.
2: Pier vs footing vs slab. I leaning more and more towards the pier option it solves several of the other issues people have brought up such as...
3: Getting all the material up there. Believe me I have thought about that issue a lot. In fact, the design I came up with uses no material longer than 20' - the biggest I'm willing to take on the top of my truck. Piers could be done one at a time so I only need to bring the material for one pier at a time. Another side story: the original cabin material was all sled'd in with horses before there were roads. This includes the brick floors and walk ways. To make matters worse my uncle insisted that the proper way to lay brick was on edge... so tons more brick were needed. Turns out he was right. 90 years later and those bricks haven't moved, cracked or worn out.
4: Pre-mix vs raw material: I'm going to let the experts work that one out. I agree with some of the posts here that the pre-mix might be under engineered for holding up a house. Could it be augmented? maybe....like I said I'm going to talk to an engineer about that one.
5: Man power: It just so happens that my nearest neighbor (about 2 miles away) is a contractor and he is just itching to help me out with his experience and his crew. The problem is this guy has more money than god and sparing no expense is a habit for him. He might suggest air lifting the wet cement in! (not kidding)
My concerns with the piers are three fold. a) digging in that rock...ugh b) I hate having steps up into my house, c) critters under the cabin (I think I have a solution for that) and d) digging in that rock...ugh!
Griz
1: Is there water available? If you would have asked last year (California drought) I would have said heck no. This year....yeah no problems. To be honest we even had steady water during the drought. On the topo maps our property is listed as "Water Gulch" :thumbsup: Side story: My great uncle homesteaded this property. He picked it because it's where you would always find the cattle at the end of the season. There was water, shade and an afternoon breeze.
2: Pier vs footing vs slab. I leaning more and more towards the pier option it solves several of the other issues people have brought up such as...
3: Getting all the material up there. Believe me I have thought about that issue a lot. In fact, the design I came up with uses no material longer than 20' - the biggest I'm willing to take on the top of my truck. Piers could be done one at a time so I only need to bring the material for one pier at a time. Another side story: the original cabin material was all sled'd in with horses before there were roads. This includes the brick floors and walk ways. To make matters worse my uncle insisted that the proper way to lay brick was on edge... so tons more brick were needed. Turns out he was right. 90 years later and those bricks haven't moved, cracked or worn out.
4: Pre-mix vs raw material: I'm going to let the experts work that one out. I agree with some of the posts here that the pre-mix might be under engineered for holding up a house. Could it be augmented? maybe....like I said I'm going to talk to an engineer about that one.
5: Man power: It just so happens that my nearest neighbor (about 2 miles away) is a contractor and he is just itching to help me out with his experience and his crew. The problem is this guy has more money than god and sparing no expense is a habit for him. He might suggest air lifting the wet cement in! (not kidding)
My concerns with the piers are three fold. a) digging in that rock...ugh b) I hate having steps up into my house, c) critters under the cabin (I think I have a solution for that) and d) digging in that rock...ugh!
Griz
/pine
Super Star Member
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Not sure what type of gravel you are referring to but around here "gravel" (unless it's river gravel) is crushed granite...and it makes harder concrete than limestone in my experience...
Also around here...it is just as easy to just crusher run (granite) and Portland cement...no need for additional fine aggregate...
One issue with mixing over delivered ready-mix is air entrainment...without an air entraining agent the finished pour will be vulnerable to freeze/thaw damage...