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Reader with Suggestion on Reinforceing Concrete

editor: There is a good bit about reinforcing concrete below.

First of all I would like to thank you (I guess for all expats) for the incredible and fantastic work that you have done. It is informative, well done, and you must have spent hundreds of hours to make it happen. You also made this site free-and indeed it is not only free it is priceless.

Having said that, with your permission, I would like to introduce my-self. My name is Paul C. and I am also an expat and married to Thai lady for long time like you. My wife’s name is Wanida. I lived in Thailand twice; the second time in Pattya and Na Jom Tien in Sunshine Condominium, right next to the Marina Condos, on Sukhumvit road.

During my stay in Thailand we build the first Cooper Smelter & Refinery in Rayong, Thailand. Actually it is between Rayong and Bang Pa next to an old rubber plantation and the Eastern Seaboard Industrial Complex.

Now we are ready to retire and within the next 6-monts we are anticipating to move to Thailand, the vicinity of Pattya/Jom Tien/Satahip/Utapao, buy some property and build our own house. The reasons for doing so are about the same as yours. (Hence the beckoning and appreciation of what you have done with the Cool House)

Presently my wife and I live in Southern California in a city of Murrieta, between Riverside and San Diego. I hope I will hear from you soon.

editor: Thanks for the kind words. PS.:

If I may, I would like to add a small token of appreciation for your work, in a form of a suggestion:

reinforcing roads and other concrete slabs

The reinforcing roads, or wire mesh that are imbedded in concrete pads such as driveway, flooring, etc., enhance the allowable bending stress of the concrete. (Concrete allowable bending stress is very small). To accomplish this task can be done two ways:

a) By pre-stressing the roads before pouring, b) By simply imbedding roads or wire mesh inside the concrete.

The “magic word” is imbedding. If the contractor is using wire mesh, for example house flooring or driveway, it is important that the wire mesh is imbedded in the middle of the slab in lieu of laying it on the top of the ground where the concrete is being poured. It is easily accomplished by tying about 1 1/2″ flat piece of a concrete block or brick to the bottom of the wire mesh before pouring concrete. This ensures the positioning of the mesh just about in the middle of the slab instead at the bottom. Now you have a re-enforced concrete. Otherwise you only have a concrete.

Depending on load condition, etc., later-on, you will end-up with cracks in the concrete. Naturally if you have tiles on the top of the concrete they will react accordingly.

Regards, Paul and Wanida C., your fans.

Normally the contractors will pour the concrete and then pull up the mesh so it sit about in the middle of the slab. However, I agree that this is hit and miss and like your suggestion a lot.

3 Comments

  1. Hi Paul

    Good points there, The slab should be 80mm with the rebar halfway through. The pouring method is difficult to inspect unless your are always on top of the job. The block method is better but I prefer the red bricks for the job, smaller and more predictable. This way you can insist on inspecting all shuttering work before any concrete is poured (which is what is done professionally of course). Its one of several very critical areas in your building construction. Dont leave it to someone else. That 10 mins spent on inspection is priceless

    BTW you should be aware that jomtien is divided into 2 separate and very different admins Chonbury and Sattahip. The break point is half way down where the second police box is on the sea front. Rumour has it that you really dont want to be located in that tambon. Its a bit risky (as was evidenced by an acquaintance of mine who once rented a small villa down there).

    The answer is, if you want to know about a place go rent somewhere and live for 3-6 months, then you really find out the warts.

    The last thing is to listen to Pattaya talking heads especially in the realty trade.

    good luck

    Robin T

  2. I would like to point out that concrete depending on the amount of cement used and the amount of Slump (more cement stronger, excessive water used weaker) is tremendously strong in compression, but not very strong in tension, hence the steel placed where the tension is. Even where some Poor Thai cannot afford steel, and uses bamboo in his concrete, it is suppose to work. ? What one has to work out is where is the tension going to be ? in any span it needs to be nearer the bottom, with a cantilever slab like a balcony, it needs to be at the top. This is where the main steel does it’s job of resisting the tension,. Some times the Structural Engineer will specify two layers of steel in a slab which can only be to resist tension in either direction I can imagine, such as a Raft type slab with walls putting pressure downwards on the out-side. Beams have steel all around but usually with the bottom steel being the larger. All concrete should have a min amount of concrete cover , usually 20m.m. if exposed to the elements. Even with that cover it is advisable to give it a protective covering of some sort like a good Acrylic paint. I have had 60 years of experience with the so called Concrete Cancer , mainly in Sydney putting up Scaffolding and Swing Stages on High Rises to repair that problem. Apparently it has been established that water penetrates bare concrete by a m.m. per year until it reaches the steel, then in one year it will go right round the steel and start to blow the concrete out with the rust expansion. With swimming pools and even other concrete structures here, they are now using hot dipped galvanised steel a lot of times.

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