One logical way to find what size and rebar requirement is to dig to a site of the back of the kitchen existing footing. After digging it you can see the size of the footing then hack a part of it to review the rebar. From then one just add a foot to the dimension to be sure and add more rebar than the existing.

I believe the developer has done studies of your soil condition by engineer and been approve to be safe by local council. By making it stronger than your existing footing you can have peace of mind. Also check by digging deeper if pilling was made, if so just follow.

Anyway you still have to dig the existing footing and its rebar when reno so as to connect the old rebar to new rebar holding each other at the cold joints.

Isn't this answers all the queries above, simple and definite without being an engineer!

Cheers

First I talked only about footing, not column. First thing first, are you disputing the suggested footing?

2nd, whether it is footing or specification for columns what you suggest TS to do? Hire engineer? Yes, that is the right way to do but that is a bomb to pay. There are shortcuts and alternatives and am suggesting if you cannot go by air go by sea, something like that. Shortcut sometime is even better and more effective, save time and effort and money.

There are many ways of solving a problem when we think out of box especially when the cost of doing it "correctly" is beyond reasonable as far as price/cost is concerned in this case.

One other think out of box or shortcuts is go to the developer and look for the architecture or structural drawing and follow. Another place to get such information is from the land office or local council (am not sure which one). The authority should have such information or request such information when approving housing projects.

So, hiring an engineer is also not a definite answer compare to what has been done by the developer more thoroughly done, than one personally hired engineer, in a big or bigger project of many houses.

It is healthy to dispute and everyone learn from each other. I was not thinking of column but only footing which is only a part of the whole reno consideration.

Cheers

New house? How long has it been. If too long time ago the developer dont give a damn to dig the files.

When your house is at hill cut area, the area has to be left 10 yrs to subside and pilling needed. Usually you can see your next neighbors are you next to one that is lower than yours and how high is yours? Or the back of your house is hill or the front of your house is higher? Then you can guess if pilling is required or not. Pile only for the column. Footing no need to pile.

Like I said dig the existing footing where you want to extend and follow accordingly.

One other way for column is to dig deep and wide till you hit hard ground, concrete cement, sand and stones are cheap, after all you need only 2 or 4 column max.

If the extension is not a big area, on top of the footing, reinforced concrete the whole extension area like a slab. As such when the extended structure were to sink or subside it has to sink the whole reinforced area.

Just visualise yourself. A table with 4 feet on a sandy area, at a beach. You sit on top and another man also go on top. All the 4 feet sink into the sand. When you put the table upside down you and one other man stand on the upside down table, what happen? The table will not sink into sand as it now has big big surface area on the sand. Another 2 men go stand together or even 6 men altogther, no problem!!!! Make the reinforced concrete normally 6 inches thick, make it 8 if you want to.

You are right, want to do do it properly, but hiring an engineer is only partly correct and may be a waste of money as nobody is checking on the work of the engineer. There is no check and balance. The major part of it is construct it correctly.

Cracks. When we talk about crack, where the crack is? Crack is not always due to subsidence. The most common problem with crack is Cold Joint and shrinkage of new concrete. What appear of a crack between the existing main building and the new extension usually is due to poor joint. As concrete cure (especially the first year) is shrink alot. As it shrink it is pulling themselves together, as such it is pulling away from the existing new building and so cracks appear there. This is only one of the reason concrete crack there due to poor cold joints. It has nothing to do with subsidence. The proper way to prevent such crack is to dig out the existing main building rebar from its beams and columns and hook join to the new concrete rebar then pour concrete. When concrete set or cure over the years as it shrink, due to the hooking of the rebar the existing building is holding the new extension from pulling away and therefore no crack at the cold joints.

There are other types of crack which also got nothing to do with subsidence or due to new extension foundation sinking/subsidence. The foundation, footing and column and beams are hook together in concrete as one piece but not the brick walls and if cracks appear between this one piece and the walls then it is due to, again, poor cold joint between them. such cracks usually appear at the top of the brick walls and beam due to wall concrete shrinkage and gravitational pull. Less obvious is the crack along the column and brick wall, and again this got nothing to do with sinking.

Why spend your money on a "suspicious" engineer (suspicious because no check and balance) when it is so much cheaper to build a slab (called slab foundation) reinforced with the footing as one single piece and yet much secure foundation

See pic of a slab foundation


This post has been edited by stevie8: Nov 17 2013, 02:32 PM

There is no need to be sarcastic. If you are so called expert give your valuable comments. When you are not a doctor do not talk like one as though you are, okie

Here we talk so that people can understand the logic. There is no need for an engineer trying to frighten others. Even with engineer calculation still many buildings (not extension,OK!) has more than 2 inches crack and some of it you can put your hand in. There is major problem with soil and the engineers failed to notice that. Do you also know that our twin towers is now not at its original site due to extended studies of the soil deep underneath that were not suitable?

This is extract from this website

http://civil-engg-world.blogspot.com/2013/...ONAS-Tower.html

"....The geotechnical survey discovered that the actual construction site was situated partially over decayed limestone deposition and rest over soft rock. After discovering this, the structure was relocated to avoid limestone deposition. The whole foundation was rested on 104 piles. To reach safe bed rock the piles were extended to depth ranging from (200-374) feet. To reach this depth, PETRONAS Tower became the structure having the deepest seated foundation of the world....."

So, having your house extension do you think you should do a extended study like our twin tower??? Small issue going beyond what is necessary. The answer my fren is you dont even for building a housing estate with landed houses and apartment blocks.

Do you see people extending thier house bring along load of concrete to test the foundation? You dont, ok! It costs you a bomb or the whole renovation cost by doing so!

I just wonder what the engineer will do and what test he will conduct and by the way you got a house? Your parents got. So you or your parents did any extension to the house and called an engineer to do it?

This post has been edited by stevie8: Nov 17 2013, 06:44 PM

When I said slab foundation so people know what it is. If I were to say raft foundation, many would not know what I was talking about. Understand this brother. Here extract from the same website and if you worry do this than to hiring a engineer. Money wisely spent on your extension than paying the engineer. See the last line, it is economy having this type of foundation and strong.

"...Raft foundation is a thick concrete slab reinforced with steel which covers the entire contact area of the structure like a thick floor....Now I shall discuss where raft foundations are required. Raft foundation is required where soils have low bearing capacity and have to support heavy structural loads. Normally structures on marshy land, soft clay and land that are made up of sanitary land fill or other materials (like debris, unconsolidated soil and solid waste etc. where differential settlement is suspected)-require raft foundation. Raft foundations are preferred in the soil that are suspected to subsidence. Subsidence may occur from different sources like change in ground water level due to climatic change specially in case expansive soil or foundation in mining area.
In one words, where deep foundation like pile foundation are not economical and feasible and isolated column footing is impracticable due to large footing size or over-lapping of neighbor footing , raft foundation is the economical solution...."

This post has been edited by stevie8: Nov 17 2013, 06:56 PM

Never mind, bro. Am not here to show off my knowledge. Am just wanting to help.

Here you go. For those who over worry too much and wanting to hire engineer and no such budget do a slab foundation. (I prefer to use the word slab) Your pilling or column no need to be big and deep hitting hard ground.

Again, if the sand is 10 feet deep and your table is 3 feet high, 2 men keep jumping on top of the table the 4 legs will go deep into the sand until it hit the top of the table. When you put the table upside down, 6 men keep jumping until the cow comes home, not an inch of the table face will sink into the sand! That is slap foundation.

Cheers

When you do not agree you can ignore, ok? Let others judge themselves From a blog is better than some so claimed to be expert. I am not a civil engineer but my knowledge and experience don't fail me. I did my house extension 2 times on 2 houses already and am going to do another. No civil engineer. I have a niece a civil engineer expert in bridges but no need for her service for my house extension, not necessary at all.

If people need only experts to comments, this is not the place for putting your queries. Go see expert and pay and get conned. "Conned" here means pay unnecessarily.

Are you? if not shut up. Otherwise, answer my question. Did you or your parent did any house reno calling or paying a civil engineer???

That's is interesting. So did the son did the load bearing and bring in equipment and load?

So, you do not want to answer my question, right? no load test no telling what kind of test, so you are lying. What kind of engineer are you? Dont mind show a copy of photo the cert or ass? And so how your brother use what to see 10 feet under the ground? Your bro got the equipment? The one empty talk is you that is why you are so defensive otherwise the conversation should have ended long before. What have you commented? Nothing but get an engineer, get an engineer....engineer...engineer, we are engineers... I have so many engineers surrounding me and none show off, hardware, IT, software, civil, mechanic, telecommunication, electronics. None says we engineers... something like that to push for a point.

Cert pls or ass

Thanks for the trophy, not throphy, mr proud engineer.

Well written. But there is something we called real world as the world we are actually living in. All these approvals and engineers specs are mostly non-existing but just rubber stamps! Draft man draw and engineer sign and stamp, local authority sign and stamp and indon construct the reno extension. No engineer come to site even step in to look at it! So, If you were to hire an engineer the most is he steps on site, curi curi test and charge you a fee. So, suspicious engineer he is because he can even signs and stamps without being on site on most occasions. That is reality otherwise please tell me all these reno extensions all of them hire engineers and so to be approved by local council? We buy the stamp only la.

Haha...Teacher teaches you learn, ok. If not when you do your spec and if you accidentally wrote an extra digit "0" it is 10X more.

The tidak apa people are also those who don't visit sites.

By the way, it is not Malaysia and to single out malaysia is most unfair. Building collapses, bridges collapsed are everywhere from Japan round the world and back to Japan and including oz your ideal country. This is the real world, not only buildings and bridges but nuclear plants included! I can google and point you to the sites but waste of time, you can google yourself.

Anybody who would bought my house(s) would be in for extra benefit with added rebar and higher grade concrete from specifications and personally supervised by me, just for your info. Wrong words. Not cut corners, spend wisely. We who understand the real world and to live with it, wise people like us like what Weikee said, we OVER DO IT!!!

And if you were to ever buy a house with extension, my advise to you is demolish it, be very careful because we are all tidak apa people and one day it would collapse on you!

Aquaria said, there are book+experience and strictly follow book only. You need experience and live with it to survive better in this imperfect world. Good to fight for ideal but you cant fight it here. First change within your group, your engineer peers.

Cheers

Finally you got it CNY soon can't start reno right away, right?