Garage and concrete slab questions

My guess is that the pole barn is the most economical. Here in PA, there are contractors who do nothing but. However, that might not be a good idea if the weather in your area is extreme.

I saved a ton of money on the concrete foundation for my 30'x15' brick patio by contacting an independent concrete guy who gave me his daily overage at a greatly reduced price. That was twelve years ago. No problems.

 

In my post below I mentioned the overage from an independent concrete contractor. You might find out what is going on in your area by way of construction. Those guys don't like to return with any overage if possible, especially if it is a long ride back.

 

For a regular slab on grade here in FL it cost me around $2.90 / sf with concrete at $112 per cubic yard. This was for a thickened edge slab (16x16 edge) and a fairly officient shape ( a rectangle with a little bump). Figure a yard for every 81 s.f. for 4" slabs, a yard for every 65 s.f. for 5" slabs. And when the concrete yard is telling you the truck is 10 yards bet on 9. They do it by wieght and typically add a little extra water with a superplasticizer so it doesn't hurt the concrete strength, saving them on the amount of raw cement and aggregate that cost them more money. You can still use ready mix (in the truck) for a 70 mile haul, but you willpay extra for the distance and the additives that extend the set up time. For any garage you will need some kind of concrete surface, so you are kind of stuck with that. You could use pavers and a pole barn, but it would not be weathertight and not really good for a garage application. If you think the fuel companies are crooks, the concrete guys are much worse here. When we were ordering the company said they were raising prices by $13 per yard so we wouldpay $112 vs. $99. When I asked why they said the aggregate yard in Dade county was POTENTIALLY being shut down by environmentalists. I asked if they got their aggregate there and they said no. I asked how it affects their price and was told they have a conference call weekly (with the other south florida concrete companies) to discuss the concrete prices and the consensus (price fixing) was a raise by 15%.

BT

 

Ouch. I agree with pretty much everything said above. Concrete trucks are notorious for coming a little short. I was going to say that around here, placed concrete flatwork has been running between $4-$5 per SF including the concrete material (which costs less than $80/CY here).

Also, I would think a preengineered metal building would be ideal for what you are doing. I am not sure what market you are in, but masonry is getting more expensive all the time around here. Though, with a preengineered metal building, you will at least have to have a turned down edge (as mentioned above) but it may even require several footings for the size you are talking about. Hope that helps.

 

I totally disagree with the previous two posts. Concrete is batched by weight but sold by volume. The correlation between the two comes from the specific gravity of the materials. No legitimate ready mix producer would ever short a customer. Concrete companies also can provide actual batch weights of what is in each load delivered. What happens in many situations is that the customer's 4" thick slab is actually 4 1/4" or more, or it might be 4" at the perimeter an 6" in the middle. Not compacting the subgrade properly will also use more concrete. If you can walk on the subgrade and make footprints, the weight of the concrete will also cause the slab to be thicker. Unfortunately many customers are their own worst enemies when it comes to preparation and finishing.

Adding superplasticizer to a load of concrete will increase the workability but it will not increase the yield. A producer will not take aggregate out of the mix if there is superplasticizer in it. It allows the cement to be used more efficiently so cement and water or just water can be removed depending on what you want to achieve. Much of the cement in a yard of concrete is wasted as the concrete itself dries out before all cement particles can hydrate. By spreading them apart with a super, you can achieve higher utilization and strengths and therefore a denser mix than if you had not used a super. If you can provide the same product and use less of our natural resources, why wouldn't you?

Residential slabs in this area are placed for around $2.50 ft2.

 

Further datapoints:

Midwest, foundation pour 3-4$/foot. PLUS grading and stone. The concrete pour is cheap.

Do look at your building codes, they may require footings below the frost line, and that is quite expensive. You can't just lay a slab, it will heave/crack.

I personally don't understand the appeal of steel buildings - they have very poor resale, hard to insulate, usually very unattractive if you get the basic package, and not flexibe to work with... They are, of course, less expensive.

If you are looking for cheap storage, it might fit your needs...

 

I built a shop out of pre-engineered concrete panels. The cost was not much more than a steel building, and the aesthetic was 100x better. There are many finishes and designs that they can produce, and the walls provide a pretty decent r-value. With an overhead radiant tube heater, and a 15' overhead door that was up and down all the time, my winter heating bill was never much over $100 for 3000sf.

 

Do you by chance work for/own a concrete batching company?

Even on formed concrete (where there is much less room for error) I have received shorter loads than the ticket says. It happens. We always add a percentage over what we figure for waste, it still tends to works out.

I agree that superplasticizer is a good product, but it costs several more $/yard here. I would also recommend getting a flyash mixture if possible, because that will save money versus a concrete mix with straight cement.

As far as the original post, a pre-engineered metal building might be one of the most cost effective ways to go, not necessarily the best looking. It depends on what is more important, the budget or aesthetics. I am a fan of masonry buildings, though they tend to be more expensive. They certainly seem to last and are low maintenance. But depending on the size, you could always stick frame a garage and use brick or siding on the face of the building. There are really lots of options. It is mostly up to your budget, what type of materials you want to use and how their costs are in your particular location. Even the pre-engineered panels mentioned above this post sounds like it might be a good option.

 

I have formed and laser graded for foundations / slabs here even using 3.5" for the overall slab thickness and still come up short with the yardages quoted to me by the companies when I generated the estimate based on 4" slab thickness. The amount needed basically comes out to about 4.5" thickness ordered. The soils here are pretty uniform sand with some small amounts of organics that compact pretty easily to 98% dry density. I don't think the weight of 60psf of wet concrete is going to cause 10% overages on jobs that already have a 10% waste factor built in by using forming of 3.5" for 4" slab depth estimates. The fact that one of their employees tells me the industry basically artificially fixes prices on the high side, I would not doubt that they are not what you might call 'legitimate' producers. I do my own estimating for construction projects that I pay for and the concrete seems to be the only area that consistantly comes up wrong. With the impending construction slowdown I can find some happiness in the thought of all that expensive equipment sitting idle for months while those crooks running the business suffer the payback for their greed. I was pleasantly surprised at the low cost of pavers so that I did not have to place another concrete order for an expanded driveway. Instead I got to rip the old concrete driveway out and deal with a nice paver company that was cost competitive (installed) with a concrete companies raw materials cost.
BT

 

I am involved with a ready mix concrete company. You should expect to get 27 cubic feet for each yard of concrete that you order. If you think that you are getting shorted, make the producer show you what he is delivering. He can do testing on your jobsite to demonstrate what he is delivering. Obviously a mistake could occur on an individual load but you should not be content to accept shortages regularly. You should be able to trust your supplier however it doesn't hurt to question anything that you don't think is correct.

Superplasticizers are good admixtures but they aren't necessary for normal placements. There are applications where they can be very useful though. And you are correct, they add $5 or so to the per cubic yard price.

There are other supplementary cementitious products besides flyash that are regularly used in concrete. Flyash is great if you have a consistent source. When the power companies burn different types of coal, that can affect the flyash characteristics. Straight cement mixes are the most unforgiving.

 

Arlie - for your intended purpose - what about asphalt over RCC (Roller Compacted Concrete)?
http://findarticles.com/p/articles/mi_m0NSX/is_2_50/ai_n11840462

 

...of mine has a "fair' size building used to store extra cars. (60`x200`) It has a poured slab, w/ "rat walls' ,around the border aprox. 16` inward. The remainder is gravel. Works good for storing less than pristine cars and saved a pile of cash. J.B.

 

A guy here in my town has taken some land(granted it's a good location and he's owned the land for 20+ years) and is developing little office/wharehouse buildings on it. Pretty slick deal. The buildings are small 7200 sq.ft. with 1800 office, the rest open box with slab. He's leasing them faster than he can build them at $6.50 a square foot and keeps bragging about the killing he's making, so he must be building them fairly inexpensively.

 

...............have to choose a vin for my `32.......... how does 0846 sound to you.??

 

Flat roofs are fairly expensive. Single ply membrane roofing is around $3 per foot. BUR or modified bitumen is around $2-2.50 per foot. Then you still have to have a supporting wall and decking system. When you add it up, the cost of the roofing system and decking will often be equal to the total cost of a prefab metal building superstructure. An apron slab (as mentioned above, but yours could be 6-8 feet wide) would be an economical alternative with a gravel infill and the prefab metal building for the superstructure. And I wish the concrete companies were more honest here, but I guess we trade the sunshine for some shady businesses. Plus I know Arlie really enjoys a good conspiracy!
BT