Possible to build house with concrete block but cover unattractive exterior?

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Old 06-21-11, 07:29 AM
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Possible to build house with concrete block but cover unattractive exterior?

I am building a house that I am trying to keep as simple and cost effective as possible by using block, but am wondering if there is a way or if there are cost effective methods of covering up the lines that are often seen separating concrete block however. I am aware of the option of split-face blocks but was wondering if there was anything else. Does textured paint cover it or make it look better? Or would going out with mud and just troweling it by hand be the most practical solution? Am trying to just get a smooth exterior finish that can look decent when painted rather than having something that looks like a cell block. Any ideas/help is appreciated.
 
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Old 06-21-11, 07:57 AM
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A stucco coating would work. Don't know all the specifics of doing it, but there are plenty of houses, walls, fences, etc, done that way out West.

Matter of fact thats one of the big upgrades to "modernize" the look of some homes. Put a smooth stucco finish over the old rough coating.

There are paints that can help cover the pores in the block, but won't do much for the joints.
 
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Old 06-21-11, 08:19 AM
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Stucco was my thought as well
 
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Old 06-21-11, 08:40 AM
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Python -

Since you are in Florida, I understand why you want concrete block. The walls can be reinforced to be used in any of the widely ranging local requirements for hurricane resistance and proximity to the coasts.

You can get a smooth surface by building the wall with a flush struck joint and not a tooled joint. This eliminates the deep "groves".

After that, apply 2 coats of Thoroseal. It is a cement based coating and not a "paint-type" coating like Drylok. The second coat usually must be apllied within a tigh time frame of 1 day after. It is a material that has been used for decades on concrete restoration and commercial coatings and has a consistance of pancake batter (gray or white) and the surface should be damp for proper bonding. The timing of the mixing the powder with water is important. It is a mess that can be cleaned up easily during construction. It also not like painting. There are other products from the same manufacturer that are more compatible for finer finishes and are coated.

It is possible to apply stucco over but the proper timing and a acrylic latex bonding material must be used for a complete, unified cement-based coating.

Dick
 
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Old 06-21-11, 02:19 PM
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I've painted a lot of concrete block homes in fla. Some were just struck block and others were stucco'd. Most in fla just apply the stucco mix over the bare block. The 2 most popular stucco finishes are a fairly smooth sand finish and a texture that is somewhat of a skip trowel effect [I don't know the proper name] The 2nd type of stucco finish is probably the most popular because it can hide a lot of defects in the block or how it was laid.

Stucco just needs primer and paint. While there are specialty masonry paints, 2 coats of a quality latex paint works and lasts as good as any. Thin the 1st coat 10-15% water, the top coat should be applied full strength.

Bare block needs to be primed with a block fill. It's similar to drylok - goes on thick and fills the pores in the block. Again a quality house paint works best for the top coat. If extra moisture protection is need an elastromeric paint can be used for the top coat on either block or stucco. I wouldn't recommend using a texture paint on either.

I always thought the main reason block was preferred in fla was because of bugs
I've always heard that a stick built house, properly built with the appropriate strappings would hold up to hurricane winds better than a masonry home that doesn't have any give.

btw - welcome to the forums Python!
 
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Old 06-21-11, 03:25 PM
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In the coastal areas wood construction is not satisfactory for projectile pretection (life safety) since that is a major factor in casualties.

FEMA has approved reinforced concrete block and reinforced poured concrete or recently listed a laminated surface of 3/4" plywood and steel plate and more plywood based on recent tests. - This is for exposure to tornadoes (up to 275 mph winds even in small tornadoes), that have greater damage (more wind and heavier debris) to homes inflicted. Hurricanes lose their real "punch" once there is any surface cover, especially trees.

Dick
 
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Old 06-22-11, 12:55 PM
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Wow, pleasantly surprised by the great feedback, thanks everyone. Was my first time reading and posting on the forum, appreciate it. I am very new to construction for what it's worth and was basically placed in a lead role as project manager with 0 experience (as in, didn't know what stucco even was, etc) by my uncle. Long story short I was an investor and decided I wanted to get more actively involved in our business venture since I'm young enough to be able to probably get a better return by having more hands on knowledge with what we're doing.

Having said that, these homes are actually not being built in FL. We are test building them here in Mississippi, but they are intended for Tanzania, East Africa. We are trying to basically do some test construction homes using different systems to compare costs and see which system is the easiest to implement, while requiring as little specialized skill as possible, since we will need to utilize local labor in Tanzania. The overall cost of the houses has to be in a certain price range for our target market out there, so we're trying to get the best product that we can for our price range.

So at this point, we are interested in trying out block because the local labor is familiar with laying block and it's cheap. We just are concerned about aesthetics now.

A stucco coating would work.
Does stucco'ing a light coat usually cost less? I was told the going rate for labor + material here is close to $6 per sqft, but does it cost less to stucco over concrete block?

You can get a smooth surface by building the wall with a flush struck joint and not a tooled joint. This eliminates the deep "groves".
I'm going to look/read into this, but does this require more skill or is this something your average bricklayer should be able to do? Do they charge more for it?

After that, apply 2 coats of Thoroseal. It is a cement based coating and not a "paint-type" coating like Drylok. The second coat usually must be apllied within a tigh time frame of 1 day after. It is a material that has been used for decades on concrete restoration and commercial coatings and has a consistance of pancake batter (gray or white) and the surface should be damp for proper bonding. The timing of the mixing the powder with water is important. It is a mess that can be cleaned up easily during construction. It also not like painting. There are other products from the same manufacturer that are more compatible for finer finishes and are coated.
After this portion here, would it be ready to be painted with standard primer and flat paint?

It is possible to apply stucco over but the proper timing and a acrylic latex bonding material must be used for a complete, unified cement-based coating.
For the last part here, do you mean to get a competely smooth cement based coating? Because if we stucco we'd be fine if it's not completely smooth, we just mainly are looking for something that's more attractive than cinder block, so a non-uniform stucco finish would suffice.

Stucco just needs primer and paint. While there are specialty masonry paints, 2 coats of a quality latex paint works and lasts as good as any. Thin the 1st coat 10-15% water, the top coat should be applied full strength.
What about adding a coloring agent to the stucco mix? Would that possibly take care of both and save money on paint+labor?

Thanks all. This is a pretty interesting project we're doing here I'm told since it's very different. One of the houses we built came from a prototype that our group invested the money to have made that was a dome structured roof w/ columns that holds it up and then the walls filled in. The other one was a system that involved shooting the walls on w/ a shotcrete application like for pools. I'm thinking if there's enough interest, it may even be a good idea to start a thread about it where people can follow along in this little experiment/adventure, it would allow people to give me ideas and advice which would be helpful since at this point I've been having to do it all on my own from scratch. Have came a long ways but am still pretty green. It could include pictures and everything and might be cool.
 
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Old 06-22-11, 02:04 PM
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"What about adding a coloring agent to the stucco mix? Would that possibly take care of both and save money on paint+labor?"

This can be done. Personally I'm not real fond of it, the color seems to fade after a few years, I think painted stucco looks better than tinted stucco...... did I mention I'm a painter

I've never used any thoroseal, don't think I've ever worked a job where it was used.... but Dick is pretty knowledgeable about that product and he'll likely be chiming in later.
 
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Old 06-22-11, 02:29 PM
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Since you did not supply the information about the location of the work, everything being said that refers to the U.S. does not carry much weight unless you want to spend a lot of time and money to determine what is doable there with the resources, materials and labor available in Tanzania.

Building a prototype in Missisippi may be good for a show and getting funding and support, but everything else is meaningless.

It is true that masonry is the most common form of construction in the highly developed and developing world, but you have to recognize what you have to deal with as far as raw materials, other products, climate and available facilities/labor skills. I learned many years ago that what works in Milwaukee may not work in Minneapolis and the reverse. Going from a prototype in Mississippi will have many failings when it is magically transported to Tanzania.

As I recall, Tanzania is an areas that may have nsuitable aggregates, so quality aggregates for stucco may be rare and cement can be costly ($10 to $50/bag) because of logistics. Building a large section of the structure is out of the question for the mass housing because of trnasportation. Wood is probably not a readily available material and power for equipments can be variable in some areas.

Get a good reading on what is really the acceptible construction and what the materials are available to make the project work reasonably initially.

South Africa, Namibia and Botswana have good concrete products that have been well accepted into the suppling the need for improved housing. South Africa is the leader because of the availability of materials and the suitability of construction for the climate and low cost housing. When I was in either Botswana or Namibia, the cement had to be obtained from the local block company that also sold great chicken over the counter during the lunch period. - Nothing beats getting to know how deep the water is before you jump in. I went to Brazil to visit construction and expected chaos, but found high quality design and construction that surpasses U.S. masonry usage and they used 6" thick block walls to support 20 story loadbearing block buildings and used video camers for inspection and all materials were pre-approved and color coded before delivery to the site with 10 or more building being built at the same time.

After 41 countries, the best advice I had from a friend was "If it does not make sense, it must be true" if you expect to change and understand what people want and need. - You certainly do not want to build Buckminster Fuller dome homes, since they have not found a home in the world yet. There are some areas of Africa that have great housing sytens ranging fron Ghana to south Africa, but they are suited for the local preferences/needs and additional funding is possible from various U.S, government sources, equipment manufacturers, USAID and others if a positive system can be proposed. - You will need a good business plan if you expect to get beyond the dreaming stage.

Sounds like a fascinating challenge and enjoyable with dealing with international situations in an ongoing process. - Good luck on your venture.

Dick
 
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Old 06-23-11, 08:28 AM
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Thanks for the amazing reply Dick.

Everything you said makes a lot of sense and are things I've thought of myself during the course of this venture upon experiencing all the different problems that came up. It felt like I was basically thrown into a situation to try to figure out the solution to the Tanzanian housing shortage by myself without having any prior experience in construction, or in doing business in Tanzania. So yeah, it certainly seems like an insurmountable obstacle. We do have a very nice hotel that we have built in TZ though so we have some crews and guys with experience for that, but the housing portion is very green right now. We basically had a prototype designed for a house in Tanzania that was meant to address a lot of the specific attributes of their weather, climate, location, available materials, etc. I wasn't actively involved in the project when it was at that point but I presume (hope?) that the decision to go with concrete was well planned out. I know for the hotel, like you mentioned, the aggregate wasnt as strong so we had to monitor the mixing manually as well as double up the amount of rebar we used since the steel wasn't as strong.

The reason we ended up in Mississippi though was because after the protoype for the Tanzania house was built, some members of the group wanted to try it out in Tz while others decided it was best to at least try it out in the states first in a more controlled environment, since if we couldnt build it here then we would have no shot of doing it there. I certainly was put in a difficult spot here since on one hand I was trying to get this project built efficiently without going over budget, using a system that none of the locals here have experience doing, with a set of plans that doesnt explain things, without the right equipment, and initially without even knowing what language the construction guys were speaking, then once getting caught up to speed on that, I was faced with trying to figure out how this system will translate to Tz. I've been in contact with our guys and engineers from the hotel project in Tz to ask them a lot of questions about the labor there, the materials, the power, etc to try to see which problems we may encounter.

One positive thing I can say at least though at least is that one of the systems we're currently trying out is easy enough to where I'm at the point that I feel comfortable that if given general labor, the right materials (dirt, concrete, rebar, etc), that I could get the house built there as it is built here from start to finish. But I now am looking into other options that may be even easier and cost effective all around. It's interesting you mention the lack of wood since that's been one re-occuring theme I've had to abide by to guide my decision making here. We are basically trying to avoid any materials that we will have a hard time getting in Tz so we haven't used any wood here either. We've used steel framing and steel truss' for the roof, with all steel and concrete walls. Since you guys seem really helpful I figure maybe showing the system could be helpful to get other insight, so it's this system: Construction, Bond Building Systems, Fort Lauderdale, Florida, FL - The process for building their houses and pictures is on their site. They supposedly have been involved in a good bit of home building using their system in developing countries.

One option I was currently in the process of looking into was framing up the entire house with steel studs, putting the roofing system on the steel studs, and then using hardie planks for the exterior. Originally I had dismissed this as an option when being told that you need OSB/plywood for support behind the hardie boards, but the other day I called the company up directly and they said it absolutely is not required and can be screwed right into steel studs. I asked around to local general contractors and they said they've seen it done as well before without any problems to the strength or integrity of the wall. It would be a much weaker wall compared with concrete of course but not weak enough to not last I was told. My framers/carpenters here say theres ways to add support to the hardie planks using steel as well. If this were feesible then it would alleviate the need to paint the planks, give a much better look to the house, and be overall a lot cheaper in terms of labor and material costs. I'm looking into what the shipping costs would be but since hardie planks don't take up a lot of space in terms of mass and we're shipping the roof over, I'm thinking this may be a good option. I was still researching it but if it was something that would seemingly fit then I would have this house built here first pretty soon. What do you guys think about hardie planks + all steel framing
 
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Old 06-23-11, 04:45 PM
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Thanx for posting the information on the corporation.

You will be like a "fish out of water" dealing with international construction in a developing/semi developed country.

The available resources and the addition items that are critical do not seem to be looked at and they can be the downfall of any imported building system. What is needed in FL is not necessary or needed in TZ. The materials have not been investigated (dirt and not aggregate?) and the labor pool for a new system are critical.

One source of funds and solution could be USAID or some other organization that may supply the money for a thorough study. They are not "gifts" and potentials and details must be provided based on the local needs, market, labor availbility (a system takes some qualified people for assembly) and the reliablr resources need to peoduce the products/components.

It looks like a real interesting and challenging adventure (sort of like doing a reconstruction study like I did in Bosnia for USAID or someone else).

Dick
 
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Old 06-24-11, 05:09 AM
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Will you be working anywhere near Moshi? My wife does a lot of work at KCMC and they have a house at the Doctors Compound.

I spend a lot of time in Central America and just got back from supervising the construction of a block house. Their method of block wall construction is quite different than in the states. They pull a string for the line of block and lay two strips of mortar on the footer. Then they set the block down into the mortar, leaving the appropriate gap between the blocks. The blocks are not buttered before setting. Then someone else comes along with a simple wooden form that they drop over the joint between blocks and they pack mortar into the joint. This method seems to reduce the experience needed to handle block.

Then for the stucco face a straight board is tacked in place vertically on the wall, spaced about 1/4 to 1/2" away from the wall. Then mortar is thrown into the gap between the board and wall and packed solid. Mortar outside the board is scraped down so that the mortar touching the board is highest. The board is then removed leaving a thin strip of smooth mortar top to bottom on the wall. The process is repeated about 6 feet down the wall and repeated until all the walls have their guide strips. Once the guide strips have dried a day they come back and throw mortar onto the wall between the guide strips starting at the top. After a 2-3 foot section has mortar a screed board is dragged down the wall. Each end of the screed board is supported by the mortar guide strips. This creates a relatively smooth, straight stucco finish between the guide strips. Low spots are easily visible and more mortar can be thrown on the wall and re-screeded. If a smoother finish is desired it is followed up with a quick, simple troweling. Very little experience or skill is required.

I've gotta get to work but the steel frame and Hardi/cement board construction is also popular. I'll try to post back with some of those construction methods and I'll see what I have for pictures.
 
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Old 06-24-11, 08:48 AM
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It sounds like you are leaning towards the steel frame & fiber cement siding. I don't have pictures of that type construction at my office but I did have some shots showing the alternate way to do cement block walls.

Here you can see the gap left between blocks. Also any poured concrete is generally left until the end so it's easy to hold boards up to the block wall for forms.


On the pile of blocks you can sort of see the simple wooden form used to hold the mortar between the blocks.


Here is the form straddling the blocks. Mortar is simply packed down from above and then the form is moved to the next joint.


Here you can see some of the guide strips of mortar on the wall below the corners of the window.
 
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Old 06-24-11, 09:21 AM
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Here's my two cents worth. I would not bother with building anything here in The States. Shipping anything over to Tanzania is very slow and expensive even for a prototype and the materials & techniques from here may not translate well to Tanzania. I think you need to work with the people, materials and methods available in country. Go over and spend a few days watching how they do things and how the people live and use their homes.

I have seen pre-fab housing made similar to portable restrooms out of HDPE. It seemed like a great idea. They are easily mass produced in the USA, shipped flat and assembled on site. Except for disaster relief in more developed countries I don't think they have caught on in most of the world. I have noticed that in many areas people do not want something that is too different. If the house is not like their traditional housing it's just not well accepted. Heck, I once thought everyone would enjoy a hot shower. Not so. Even when the hot/warm water is just a turn of the knob some will stick with the cold water that they know and trust.
---
I have not done any construction in TZ but have seen a fair bit similar to what you are considering in Costa Rica. They are not built USA style with steel studs for structure. Almost always there is a steel support structure usually with square tubing for corners and then spaced down the length of exterior walls which support the steel roof trusses, similar to a commercial steel shell building here in the states (Except there are no custom beams or girders. Generic ladder truss is probably the only thing not locally made from regular stick material). Then steel studs are used as required to provide support for the fiber cement siding and to create interior partitions. The steel studs do not provide real structural support so they tend to be used sparingly and are spaced as needed.

In lower cost construction the exterior cement siding is it and there is no interior sheeting. This method eventually poses a problem when thieves figure out that it is easier to break through the wall than to mess with bars over the windows & doors so sometimes those houses end up being retrofitted with poured concrete or cement blocks to fill in the walls to increase security.
 
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Old 06-24-11, 09:59 AM
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The type of construction seen in Dane's photos is very common throught the world because it is very strong, durable and produced using available materials and labor. Few people recognize the benefits of using local labor and creating trades and stability, especially when it comes time to get any outside investment/funding.

Even the Bricklayers Union (contracted by a funding organization) was strong in the training of the Polish people to provide housing using local materials, skills to provide stability and acceptible /tradition all housing for the economy immediately after the break-away from the old USSR. It eventually evolved into masontu high/mid rise housing, just as what is acceptible in most of the world.

I really don't see the logic of the pilasters in the homes shown in the photos because of the loads that can easiily be handled by the 6x8x16 block that are the standard in many parts of the world since they can easily handle any loads for those structures or even 10 story apartments. - A little too problematic, time consuming and costly, especially when looking at the South Africa methods, but that is the tradition that is hard to change.

Dick
 
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Old 06-29-11, 11:26 AM
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Will you be working anywhere near Moshi? My wife does a lot of work at KCMC and they have a house at the Doctors Compound.
Not sure how far Moshi is but it sounds familiar. I'll be near Morogoro/Dodoma/Dar es Salaam.

The available resources and the addition items that are critical do not seem to be looked at and they can be the downfall of any imported building system. What is needed in FL is not necessary or needed in TZ. The materials have not been investigated (dirt and not aggregate?) and the labor pool for a new system are critical.

One source of funds and solution could be USAID or some other organization that may supply the money for a thorough study. They are not "gifts" and potentials and details must be provided based on the local needs, market, labor availbility (a system takes some qualified people for assembly) and the reliablr resources need to peoduce the products/components.

It looks like a real interesting and challenging adventure (sort of like doing a reconstruction study like I did in Bosnia for USAID or someone else).
Yeah, I've gone through our material listing to look at all the small things that we may take for granted in the states to see if it would be available in TZ since without it we'd be stuck, as you say. Something like self-tapping screws that allows for screwing into metal studs would be very important and probably not available there I don't think. I will look into USAID to see if they would assist us at all.

It sounds like you are leaning towards the steel frame & fiber cement siding. I don't have pictures of that type construction at my office but I did have some shots showing the alternate way to do cement block walls.
I was looking into the fiber cement siding but wasn't convinced that having fiber cement with no OSB support would be good. I'm still looking into how available it is to maybe have it sent from South Africa possibly but have geared back towards the block option because I've been discussing with our engineers in TZ and they say that 90% of construction there is done with block. He said the materials are very available and the local labor is very familiar with the very process I mentioned to him of block walls with a stucco'd exterior. I'm not sure what system they use for their block laying but the one in your pictures looks interesting.

Will update thread periodically on how things are going. Should be interesting.
 
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Old 06-29-11, 12:28 PM
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Block or brick are the most common materials for residential housing in the world.

If there is clay brick can be available, the quality may be low if you need uniformity or strength depending on the minerology, manufacturing equipment AND firing temperatures. In many area "mud" brick are just molded and dried. Unfortunately, the number of available shapes and sizes are severly limiting and reinforcement can be very difficult.

Concrete block are usually used because they are made from local "hard aggregates" and a relatively small amount of cement that can easily and cheaply be transported from anywhere. Because of the explosive expansion in China it imports cement because wood is not an acceptible material and bad for ecology (some may even come from the U.S.). They would make the most out of the samll amount of arable land they have. The block sizes are usually controlled by local customs. In many places a standard unit is 6" thick, but in the U.S., the standard is 8" or 12" thick because or basement traditions (retaining soil) and the number of high walls. Additional shapes can also be made if there is sufficient demands. Any size can be reinforced as required for wind or seismic, but usually structural reinforcement is not needed. Some reinforcement for continuity around openings or on the top course is common.

Dick
 
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Old 06-29-11, 01:14 PM
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Ah, you are more along the center coastal area. Moshi is north central close to Mt. Kilimanjaro and the town of Arusha.

Yes, screw fasteners could be a problem. Not only sourcing the fasteners but the tools to install them. Cordless tools are uncommon and the power has not been very reliable this year because of the drought (little hydroelectric) so corded tools could be useless without a generator. More reasons why masonry is so common. Most mixers are gasoline powered and if that breaks down they just dig a shallow hole in the ground and mix mortar in the hole. Need to do a concrete slab... no need for the mixer. Just put the sand, gravel and cement in the area to be poured, add water and a bunch of guys with shovels to mix it in place. It's amazing what can be done with almost nothing.
 
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