hello, I plan to buy a lot soon and we've been scouting around as to how to build a house on a budget. My husband and I came across a company building houses with prefabricated slabs which comes in .60 and .90mwidthx110m.x 2" or 3" depending on your desire for low and medium cost houses. Imagine they can build a 36sq.m. house in just 7 days or a 110sqm. with a two storey in just 14 days. On a second floor they will just install slabs not the conventional way of pouring concrete on the second floor. What is conventional is the pouring of concrete for the foundations and columns. Does anyone know how to compute for this slabs. They claim they can put up with the 3000psi. their slabs doesn't have rebars but gravita, cement and sand. Their project transpired from the creation of leggo blocks for children. If you want to add another room, or change the design, you can detach the slabs. Can you give me your own opinion? Do you have a formula for the slabs? tnx.

 

First, check out the company with the Dept Of Consumer Affairs, then get a copy of the plans from them and show them to an architect. You may want to hire the architect to oversee the job.

 

In all the countries (37) I have studied construction, I have never found a precast assembly that sucessfully works without the panels being reinforced with steel. This is for handling and for strength, especially in thin panels.

What is "gravita"? The only information I get on "gravita" is related to lead processing and batteries.

All precast structures have a possible weak/critical point, which is the connection of the slabs that provide structural stability.

When you mentioned Lego block, the concept of ICF comes to mind. This is the process of stacking polystyrene foam blocks and filling with concrete. This is really not low cost or easy for a DIYer.

A better description would help to provide an opinion.

Dick

 

Well to tell you honestly, my father was an architect and we managed to put up a construction company a long time ago. But since he passed away in 1998, my mother decided to close the company because neither me (an interior designer) nor my sister (personnel management background) is unlikely to manage the company accdg. to her. We get our projects from the local government. While there were undergoing projects, some companies go to us and introduce their prefab. I am knowledgeable of the styrofoam with small rebars (probably 9mm) used in prefab for interior walls but just like you we doubted the strength especially when strong storm and earthquakes appear. Although it's cheaper but it was new in the market. Now big contractors apply this to their housing projects and the other one which I recently mentioned.
Actually, now i have a problem,we hope to buy this commercial lot which we plan to build our own house (because it's situated in a village)and convince him to use the slab.
we will have to attend the seminar as to how to install it. The good thing about this, you can just remove the roof easily and add more floors if we want to convert this into commercial building. They will probably adjust the columns and beams to a bigger size before putting up the second floor. I doubt if this company will give me the specs for the slabs. Because its confidential. They will only teach us how to install it.
Gravel's size is about 3/4". Gravita is like a pebble size. Much smaller than gravel.
How about checking on the internet? And tell me what you think. It's very interesting to note, that every year new things in the construction business are being developed and I hope I am not left behind. I hope to hear from you guys. Tnx for your opinion.

 

moniquet -

In what part of the world do you live and intend to develop your structure? - I could guess, but I learned long ago to not assume anything when it comes to construction.

For centuries and in very advanced modern areas, umit masonry (brick, block, etc.) has been proven to be the most commonly used material for residential construction in the world whether 1 story or 20 stories. - This is because the the ability to use uniform, controled units that fit many different details and structural requirements. The cost and speed of construction are also important even though it works for an individual building his own home.

Precast usually is more "industrialized" beause of the manufacturing controls required and the equipment needed during construction. It can be good for properly desgned large, repetitive projects, since the engineering and problems with details and connections can be developed to overcome some of the deficiencies. When a structural system is used in the wrong areas, disasters can occur such as the deaths in an earthquake disaster in Albania, which was based on a Russian sytem that had worked elsewhere.

There is no question that you can create a "one of a kind" precast panel system structure that will serve the purpose for a period in that local condition. Any "slab" that can be detached and move easily is just creating a "house of cards" or a structure of dominos. Any time you can just remove a roof and add another floor, you must be positive that you have a sound structural system, which can be difficult with a precast system.

There are some very good precast systems in the world, but they must be produced in a factory to obtain the performance necessary. Doing a do it yourself panel is very dangerous since it is costly and very difficult to acheive the quality and tolerences possible in a factory. - Just don't spen money on a seminar since it is obvious the system has really not be proven and established in accordance with your local codes and stadards.

In your example, you mentioned you would have to remove/adjust the columns if you add a second level because the walls are not loadbearing. This would be a major change because it would entail destroying the first floor if it was not designed correctly for the addition. This is closer to a demolition than a addition.

Good luck -

Dick

 

Yes I understand what you mean, Dick. I have the same thought too. But I just don't understand why this company won an award. It has passed several tests already. I will really need to talk to their engineer because of the business proposal I would like to put in front of the property. I plan to put 2 commercial units in front while our house sits in the back. Sounds awkward huh? This is to augment our future bank loans. Well please check this website vazbilt.com Come to think of it, if you are building a two or more floors and you are using wood as subflooring, i thought those panels would utilize the same thing if they are to compute the load bearings. If they have become successful in their business, you can also inquire from them and probably make investments. In that way, you can provide jobs for unemployed. And who knows you will be the first to introduce it in your area. But there is also one question, in our economy, people who are unemployed just have to find a way to make a living, so they can afford to buy homes. What a dilemma huh?
In 1998, we already felt the downfall of construction business. We lost over $100,000.00 from several projects because our clients failed to pay due corruption and not only that, most contractors have experienced it to from private clients. Sad to say.

 

moniquet -

I looked at the Vazbuilt site and found very little good information that really said something factual. It looks like a "smoke and morrors" situation to use an American term.

In one of the photos, I did get to see the sytem and it appeared to be an older typical post system with the precast concrete panels between to columns. There seemed to a big emphasis on having "textured" on both sides of a thin panel.

Based on the thicknesses you described, I would seriously doubt the structural adequacy of the system if it was built so the panels could be relocated.

As a structural engineer, I would not like to leave anything behind if a serious occuance occured (typhoon, earthquake, etc.). I would definitely not want to be in such a unit based on the information provided. I would much rather be in an Indian apartment built out of concrete block since that is far superior.

If you are considering doing it yourself, I would have second thoughts because there is not justifaction to allow an amateur to build a commercial building in that manner.