The guarantee of reliability and durability of any structure is the foundation. Even the strongest walls without a normal foundation will gradually collapse, and reinforcement is usually used to make it strong. But it also needs to be connected correctly in order to end up with a strong structure that can withstand the weight of the entire building. That is why the reinforcement knitting process requires special attention and careful approach.
In order to create a solid foundation for the foundation, individual metal rods can be welded together. But this method is now used much less often than knitting for a number of reasons.
Firstly, with independent construction, the welding process is usually impossible, because few people perfectly know all the subtleties and nuances of this business, so it is much easier to turn to knitting. Moreover, it also happens much faster.
Secondly, oxidizing processes may gradually begin to develop in the welding places, which means that the welded seam will become not so strong, and the foundation will lose some of its reliability. When tying reinforcement, the risk of corrosion is significantly reduced, which becomes another advantage of this method.
Thirdly, when welding, especially incorrectly, the structure of the metal is disturbed, which does not have a very good effect on the final quality of work. If the binding of the reinforcement is done correctly, then the foundation, lintels and other reinforced concrete structures will be reliable and durable. But the emphasis here must be made precisely on the correctness of the work.
Reinforcement knitting materials
To knit reinforcement, you must first buy everything you need. First of all, this is the reinforcement itself: steel rods of a certain diameter and length are used. The reliability and strength of the finished foundation directly depends on the thickness of the reinforcement, and the rods should not be less than 6 mm in diameter. In length, basically, all rods are standard – from 6 meters. It is better to purchase fittings with delivery: it is convenient and will save time and effort spent on the construction of the foundation. It is also worth paying attention to the surface of the reinforcement, because there are smooth products, and there are rods with notches, ridges, corrugations. The latter are distinguished by better adhesion to concrete, therefore, as a result, a more durable structure is obtained.
Metal rods are connected either with wire or with plastic clamps. And it is the quality of these connecting elements that directly affects the integrity and strength.
The wire for tying reinforcement is selected with a round cross section and a diameter of 1.2-1.4 mm: if you take a thinner one, then it will not cope with the load, and if it is thicker, it will be difficult to bend it. Annealed steel wire, which is usually sold in coils, is excellent for this purpose. It bends easily, quickly takes the desired shape, but at the same time it is characterized by high strength and durability. It is better not to use unbaked wire for these purposes, it is much more difficult to work with it: it is difficult to bend it, it often breaks, but if necessary it can be turned into baked wire. So, it is enough to hold it over an open fire, and then leave it to cool in air for half an hour.
For knitting, you will need pieces of wire 25-30 cm long: it is not very convenient to cut or bite off the necessary piece each time, therefore experienced experts recommend folding the wire several times, observing the length necessary for work, and then simply cut the folds with a grinder. Thus, in a few minutes all the elements will be ready, and you will not have to be distracted for constant cutting.
Nowadays, plastic clamps are becoming more and more popular, but many builders remain conservative and do not trust this method of fastening. Nevertheless, the use of clamps provides reliable fixation of the reinforcement, but it is also associated with many subtleties. So, a “bare” frame does not withstand dynamic loads, and if you incorrectly step on the upper elements of the entire structure during assembly or fill it incorrectly with concrete, then some fasteners may not withstand and crack. Vibration equipment will also need to be used with extreme caution when compacting concrete. The obvious advantage of plastic clamps is the simplest process of using them, because you just need to tighten the clamp well at the junction of the two rods, and this can be done quickly and easily.
Rebar tying tools
Of course, you can knit wire by hand, but the process will be simpler, faster and more efficient if you use special tools for this. So, you can use a hook for knitting reinforcement: there are a lot of these in hardware stores, and buying them is not a problem. You can find both the most common models and screw and semi-automatic hooks: although they facilitate the work, they still require the application of physical force, even if not on the rotation of the hook, but on the pulling of the tool. Many professionals say that store hooks are not always convenient, they are short, and they rust quickly, so they advise you to make such a tool for yourself: in the end, you can save money and make the future knitting process more convenient. To do this, you may need a piece of corrugated reinforcement, and a bearing can be built into the handle to make it easier to work. For these purposes, a nail is also suitable, which can be used as an attachment for a screwdriver.
An alternative to hooks and all homemade products is a rebar knitting gun. This is a device that greatly simplifies and automates the entire process and will become simply irreplaceable when it comes to large-scale construction. The device itself spins the wire with the required force and to a certain extent in a record time – 0.8 s. In addition, such devices weigh a little, so the second hand can be free to hold the mount. Depending on the diameter of the reinforcement, a specific pistol model is selected, and the modern assortment allows you to select equipment for any diameter of steel rods. Due to the high cost of this device, it makes sense to buy it only for large construction companies.
At home, you can create an alternative to a gun for tying reinforcement and convert a conventional screwdriver for this: the drill will not work because of the higher rotation speed. A kind of crochet hook is inserted into the tool holder, which can be made independently from a wire with a cross section of 4 mm, a thick chopped off nail, a piece of electrode, etc. You don’t have to rotate with your own hands – you just need to press the button and hold the tool firmly.
With a gun, knitting of reinforcement is 5-7 times faster than using a hook, but this method also has its drawbacks. It is very poorly suited for hard-to-reach places, consumes more wire and needs regular battery recharging or connection to the electrical network.
Methods and schemes for knitting reinforcement
First of all, it is necessary to prepare all the materials for installation, transfer them to the installation site, if necessary, align the reinforcement and place plastic clips under it, which are placed between the reinforcement and the formwork and are necessary so that individual parts of the reinforcement do not stick out from under the concrete. Now you can make a bundle. Rebar tying can take place in several ways, depending on the tools and materials used.
So, if self-tightening plastic clamps are used for knitting, then no questions can arise here in principle, and most importantly, tighten them well. The situation is even simpler with a pistol, which does everything itself literally in an instant. The most difficult and laborious is the process of tying reinforcement using a wire and a hook: several basic methods and techniques are used.
Today, there are many options to tie the reinforcement, which differ in where the wire is bent. In principle, in terms of reliability and strength, all options are almost the same, and everyone can choose the technique that is most convenient for him.
Method number 1
The simplest and most common option, which includes the following sequence of actions:
- fold the piece of wire in half;
- we pass the wire under the reinforcement, to the place where the two rods are connected;
- we pass the hook into the loop of the wire;
- we pull the free end of the wire with our fingers to the hook and put it on it, bending it slightly;
- we begin the rotational movements of the hook, twisting both ends of the wire;
- after 3-5 turns, when the connection is securely fastened, the hook can be removed from the loop.
Method number 2
The process has a lot in common with the previous one, but is still slightly different:
- we fold the wire in half and put it under the reinforcement, to the required connection point;
- crochet the loop;
- we bend the second end through the hook, so that an O-shaped loop is formed as a result;
- we twist the resulting loop until a reliable twist is achieved, and then we take out the hook.
Method number 3
According to many experts, this method is the most convenient, since it frees one hand:
- we start the wire under the reinforcement;
- insert a hook into the loop and hook the second end of the wire with it;
- bend the wire down;
- pull the hook towards you, twist it several times, and you’re done.
Method number 4
- fold the wire in half again and put it under the armature;
- press it well against the rod, and bend the ends towards ourselves;
- insert the hook, make a few turns and take out the hook.
This method allows you to get a more reliable twist. The most experienced craftsmen advise to bend the wire before twisting, so as not to make a lot of turns, because reliability will not increase, but there is a possibility that the wire will simply break. The optimal number of revolutions is 3-5.
As you can see, all methods are very similar, and differ only in nuances. If you need to knit reinforcement with your own hands, then after several attempts you can get used and choose the best option for yourself. Some craftsmen claim that the hand knitting process is simplified by using screw hooks, but this is a matter of technique and habit.
Tying reinforcement is not the easiest thing to do, but, in principle, it can be done even by the most inexperienced craftsman. You just need to stock up on the necessary tools, choose the appropriate knitting method and get started. Of course, using plastic clamps is the easiest and cheapest way, and a special knitting gun is even faster, but it will be very expensive, so many still use a special hook: even though it works longer, but with a certain skill it is not difficult, but in the end strong connections are obtained.