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Making your own concrete
This is a typical concrete mixer to mix concrete and mortar to lay bricks used on site, they can be electric or have a petrol engine.
Stepped foundations, when the ground is not flat it is necessary to lay the foundations with steps in them, so that the foundations are level for the bricklayers to lay bricks on them. See the picture this is a typical way of laying the foundations.
This is one short concrete stump with ants capping; These type of stumps could be used up to 2.4 meter high under the houses, after that a bigger stump would be required.
Making your own concrete
Making your own concrete on site from scratch
Dear readers, this post is the continuation of our last post, Australia affordable houses, where we were talking about, how we build these affordable house in the sixties, when I came to Australia, we had reached a point where we were about to explain how we make our own concrete on site. Now, let me explain what is meant by concrete in buildings and how it is made would be good to know; if during your life you are going to do any sort of renovations, it would be useful to know how to make your own concrete properly, so that you might understand what is required and how and why it must be done in certain ways, you will find it written in this hub. Some people might say here that today thing are usually done in a different way, so why bother to tell us all this stuff about how to mix concrete properly, when we can buy the concrete ready mixed by truckload, or in bags and all you have to do is to add water to make concrete.
Here I would like to say, that perhaps today in the big cities and large towns, you may not need to know what I am going to write here, because most thing are ready made: but anyhow, I am still going to write how concrete is made for the outback, and for those people that happen to live in a poor country, and for them it would be helpful to know how concrete is made from scratch.
Anyhow, it would be helpful to know how concrete is made from scratch, because that is the only way if you don’t want to make costly mistakes when you build something using cement and other building materials. Therefore, let me tell you how we were mixing our own concrete in the sixties and also what is usually required to do that and how it is supposed to be done, if you want a good job done and the concrete to last a long time.
By the way here we need to clarify one thing as I am worried that some people might not be sure what is meant by the word concrete, because usually they would replace it with the word cement; on building the word concrete means all the element mixed together able to harden to a solid consistency within a certain length of time, therefore it has got to be done the right way.
One of the most important things while mixing concrete is that the concrete should be well mixed and to a workable consistency using the least amount of water possible, because if too much water is used then the concrete becomes weaker, therefore it must be done properly.
Usually concreting and other jobs are done according to its specifications, you see any good firm that makes building plans, which may be just a small house or something else of more importance, and they have to writes also the specification how the job needs to be done. In these specifications it will be written what material to use how to use it and also the quantity and quality required. Therefore, to concrete say a foundation for an average small house, the specification written in those times could usually say that the concrete should be mixed to a consistency at least 1 to 6; for people that knew this it meant that to mix the concrete you should use 1 part of Portland cement 2 parts of river sand and 4 parts of gravel (aggregate) and mix it as required until an even consistency is achieved. For the stumps usually would be a bit more cement than the foundations. But I have to say that sometimes even these rules had to be changed a bit depending on the material that could be delivered on that local site.
Now let us say that we are ready to start mixing the first batch of concrete, as we have made everything ready, and everything has been delivered. To make concrete you need at least four elements of materials plus clean water; 1 Portland cement, 2 washed river sand, 3 clean or washed gravel and 4 reinforcement steel rods, and also it is helpful if you have a mixer if you have to mix a large amount of concrete, because to mix by hand is hard work and the concrete needs to be well mixed.
Now let us start the mixer and make the first batch, while the mixer is turning around, the very first thing you put in the mixer is water, one must be careful not to put too much water to start with, it has got to be just enough to mix everything to a certain consistency, so let us say that we put 8 litres of water (the amount of water can be different, since it depends on the amount of water that is already in the (sand gravel) aggregate) then we put in the mixer cement, next is the river sand twice as much as the cement and then the clean gravel 4 time as much as the cement; here the mixer is going around and mixing everything together.
For people that do this job all the time it is easy for them to see if the concrete that is being mixed has the right consistency required; if it is too dry just add a bit of water and if it is too wet you have to add a bit of everything else. There you are it is not too hard if you know how to do it.
What I have written above here applies only to house building of less importance, for building that are large and important the concrete needs to be to a very high standard and specifications.
Concrete requires team work
To concrete usually requires team work
In order to concrete well and do a fair amount of work on these houses you need a team. Our team was usually three of us, I as builder labour, John as bricklayer and Con the contractor who was a bricklayer and concreter. So I was usually on the mixer mixing the concrete, one was with a wheelbarrow taking the concrete from the mixer to the foundations that we were concreting and one was fixing the concrete in place.
Fixing the concrete for the foundation was physically the lightest job, when we were mixing the concrete with this mixer on site, but it also was/is the most responsible job, because while concreting the foundations first of all you have to make sure that the steel rods reinforcement was in the right position, at the same time you had to pack the concrete down and then the concrete in the foundations has to be finished level, this was easy when the ground was level, but when the ground was not level, it was necessary that some steps were made and they had to be to gauge, which was equal to the thickness of one or two laid bricks or more, or perhaps the thickness of a laid block, if blocks were going to be used to build the walls on this foundation, whatever was going to be used to lay on the foundations, we had to try to make an adjustment while we were laying the foundations; therefore this was the job for the experts, at that time it was not that hard, because mixing by hand even using a mixer was a slow job, so the bloke that was fixing the concrete had plenty of time to do his job right.
What I have written above is how we used to lay some small foundations in the early sixties, which are much the same as we would lay foundations today, except that today we just order concrete already mixed, but we have to be really ready with everything and everything has got to be in the right place, because the concrete ready-mix truck will unload its concrete very quickly, so there is no time to do anything else except to fix the concrete at the right level as quickly as possible and as required.
Concreting stumps on site
Concreting stumps on site
Now let me go back again to the early sixties, when we were concreting these stumps on site, as this is not done very much today, the reasons for this change it is because the buildings have gradually changed in many ways and also today some of these stumps can be made in a concrete factory and when cured can be delivered to the building site, where the worker can erect them as required. There are other reasons also and later on we will be looking at this also.
To concrete these stumps on site we had some steel forms of various length, and these forms were assembled together with steel pins, so we first of all we would assemble these steel forms and then start to mix concrete, we had also make sure that the stumps were exactly in the right place by using the marked profiles and tight line between them.
In this case it was an easy job for the fellow that is mixing concrete, but a lot harder for the blokes that had to pour the concrete in the stumps formwork and make sure that the stump was exactly in the right place and finished at the right height and were also plumb (perfect vertical position). It was also necessary that some reinforcing rods were placed in the right position with a purpose made devise. These are how we made those onsite stumps in the sixties.
These concrete stumps that we made in the sixties were better that the timber stumps that they were replacing, because it was an improvement as they did not rot with the passing of time and the white ants would not eat them, as they did with the timber stumps. Here we could say that these concrete stumps on site were easy to make, if you knew the procedure, in fact it was easier to make a set of stumps than to fix concrete stumps made in the factory, as there was no heavy lifting involved.
But although these concrete stumps were easy to make, they would be hard to move to a different position. So to anyone that is going to attempt to dig out these stumps to move them to a new position, they better think twice because I tell you that the part that is under the ground is a lot larger than the stumps at the top. Remember what I said in our previous hub, we had to dig a hole sixty centimetre dip in the natural ground, and at the bottom should be a level base not less than forty centimetres square.
I believe that we have said enough in this post as we have explained the work that we did on this affordable houses and we will be coming back to talk about more building work in our next post, house building in Brisbane. See you soon.