The more experience I gained with ISOTEX blocks, the more I marveled at how perfectly developed this more than 30-year-old technology is. For example, I knew from the methodological materials that on the side of the corner block a continuous block is supposed to come, but I didn’t understand why.
At first glance, it is exactly the same block as the UNI block, only slightly shorter. So why complicate the delivery with another type of blocks? Do these continuous blocks have higher strength and strengthen the corners? Why do these blocks have grooves for reinforcing wires from above and below? When UNI blocks have these grooves only on one side and on the other side the partitions form a solid base.
By about the third row, I understood the principle. 🙂 The secret is that they are “shorter”. Namely, the fact that the blocks should be put together is clear to anyone who has ever built something. It is also clear that concrete is being poured into the blocks that actually form the lost formwork. But the way the blocks are arranged internally is unique. These contain internal baffles to ensure sufficient strength of the blocks and here is the “magic”! Despite the fact that you are laying the blocks on the binding, over the middle of the block, the next block is one row higher, all the partitions across all the rows are nicely under each other! This ensures an even distribution of the concrete, which forms nice solid posts inside. And in order for it to work like this, it is necessary to use shorter continuous blocks in the corners, which nicely define the spacing of the internal partitions.
Unlike UNI blocks, these continuous blocks are asymmetric, i.e. One side has a shorter distance to the partition. And it is this side that must be adjacent to the corner block. And depending on whether the corner is left or right, then you have to rotate the continuous block accordingly. That is why it is necessary to have grooves for reinforcement on both sides. Since the UNI blocks are symmetrical, turning them upside down makes no sense, and the reinforcement grooves are only on one side. They are simply placed with the thermal insulation on the outside and the groove for the reinforcing wires on top. It’s simple there. But with continuous blocks, care must be taken not to give wider spacing to the corner block. This would then lead to the loss of the principle of vertical covers of the ribbing, which, I estimate, will lead to a lower strength of the structure.
Another trick is the corner blocks. From the methodological materials, it is clear that every other block must be cut in half to create a bond. For this purpose, these blocks have a distinct groove on both sides. You don’t have to measure anything, estimate anything. You just put the saw on the groove and it makes a nice straight cut. I believe the groove is there for this very reason. There is no vertical groove on other blocks. I like technologies that are thought out in detail.
And don’t worry about throwing away the other halves of the corner blocks. Rarely does your wall work out in such a way that the binding fits exactly on the entire block. Although it is not impossible. It is enough to give precise instructions to the architect, in which multiples the lengths of the individual walls should be. However, if you happen to have a gap in the middle of the wall, the offcuts from the corner blocks usually fill the gap well. At most, minor trimming is required. Corner blocks, like continuous blocks, are double-sided. That is Trimmed off-cuts that are asymmetrical can be rotated to maximize the vertical coverage of the crossbars.
My mistakes
As I write in the introduction, it took me a while to understand these principles. Even though I have watched all the instructional videos from ISOTEX and others that I have found on the internet about the use of this material. The manufacturer supplied a nice color brochure with the blocks, and even though this information is basically there, it is not so half-hearted that a layman without experience can understand it right away. So it happened to me that in some places these principles were not fully observed, i.e. the transverse partitions are not completely under each other. But since it is in places where the wall is very short (1 to 3 meters), I believe that it will not be such a problem. The corners will strengthen the wall sufficiently. We have a very cornered house. 🙂 Just the corner after corner. In addition, according to the architect’s instructions, we do not skimp on reinforcement. In each row, two centimeter reinforcing wires running parallel. This gives a very strong strength.
A couple of times I’ve had the UNI block upside down for some inexplicable reason, which I didn’t notice until I was laying the reinforcing wire. Suddenly there was nowhere to put it. Instead of turning the nicely fitted and level block, I simply cut a slot in it. It was faster than taking the line apart and refitting. Again, I do not believe that this would negatively affect the overall strength of the structure.
My gadgets
During construction, I used some simplifications that ISOTEX does not write about. Great emphasis is placed in the methodology on the correct laying of the first row. I underline this! If you lay the first row perfectly straight, then laying the other rows is a piece of cake and it goes very quickly. On straight sections, I achieved a laying speed of 1 running meter in 10 seconds. In the next article, I will write how to achieve such a pace and how to accelerate it even more. However, when the bottom row is not straight and it is necessary to align the blocks more significantly, it significantly slows down the work.
The first row must fit not only dimensionally, so that the corners correspond to the dimensions and placement of the houses according to the project u. It is also necessary to hold the horizontal plane, which is a little more difficult. Especially if you have a larger house and an uneven foundation. I managed to catch both and the almost 2 cm difference between the concrete plane on one and the other side of the house as well. At one wall, however, I missed the plane of the blocks. Not that I didn’t notice, but the concrete in this spot was so uneven (centimeter bumps) and overall higher than the other side that I couldn’t level it better unless I raised the height of that part. I thought I’d make it up in the second row. Although I eventually made it up to the fourth row, this is due to my inexperience with this activity and probably also the influence of the sun.
And the trick? Of course, it is possible to underlay the slanted block on the lower side with small scraps from the blocks, but I found it a suitable combination to grind the higher part of the lower block. Due to the nature of the material, coarser sandpaper is sufficient for this, and when it is put into the drill, it goes very quickly.
I will save further experiences for another article.
So I definitely recommend ISOTEX! The longer I work with it, the more excited I get about it. The speed of construction is admirable, the thermal properties shocked the designer. He had never encountered such an insulated object here. I wish I had a commission for every block you buy based on my referral. 🙂 But next time I will also mention something negative.
3 comments
Hi Vit, i just read a part of your stories regarding your choise for Crete, the purchase of a plot of land and the making of a foundationd for the building of your home and on Crete. Its very interesting because we are also looking at the possibilities of building our own house in Greece and perhaps also Crete. I also find the method of building with ISOTEX blocks very interesting. I had already read something about this on the internet and then saw your blog. We are still in the initial phase and are looking at what the possibilities may be and what and how we can and want to do it. We do not yet have any concrete plans or a house or plot of land in mind. I saw your blog “How to build on the basis of ISOTEX”. I am curious how you did this. I find this very interesting and would very much like to see it. However, when I open the blog I see 3 lines of text and that is it. Is it possible that you still need to update this blog or am I doing something wrong? Hopefully you can send me a message to see what I am doing wrong. Thank you in advance for your message and I look forward to your to see it. However, when I open the blog I see 3 lines of text and that is it. Is it possible that you still need to update this blog or am I doing something wrong? Hopefully you can send me a message to see what I am doing wrong. Thank you in advance for your message and I look forward to your Kind regards, Ron
Thanks, Ron, for your question! Unfortunately, a few months ago some posts disappeared from our blog. I don’t know how it happened. It could be a hacker or some inattention on my wife’s part. 🙂 Since we were going through some kind of internal crisis, I didn’t have the strength to publish it again. The manuscript also disappeared from my computer. 🙁 But I have to rebuild it soon somehow! I like ISOTEX a lot, it’s very fast and relatively cheap, only one problem is that it needs skilled workers to pour the concrete. Maybe I’ll write a new article on this very topic. Shipping costs are also significant , but if your plot will be near Heraklion or Chania, it will not be so dramatic.Shipping from Italy to Heraklion was about half of the total shipping cost in our case!
Hi Vit, Thank you very much for your message, it took a while before I had the opportunity to read the message. I hope you are doing well and the construction is progressing steadily. Too bad you had problems with grinding the messages. Hopefully you can still find them somewhere on your computer. Thank you for explaining the difficulties you experienced during the construction and your explanation to others to prevent this. All beginnings are difficult and certainly if you are not used to doing this, but you are inventive and know how to achieve it in a beautiful way. Now that I have read your message I have become even more enthusiastic about Isotex blocks. What you indicate that the 1st layer of blocker must be laid properly is indeed very important, after all, it is the basis for all the layers that follow. It is also good that you indicate that you have to pay close attention to which blocks you use at the corners, a very useful tip that will make things a lot easier if you do it right the first time. You write that you use reinforcement wires according to the architect’s instructions, but are they 2 cm thick or am I misunderstanding this? Have you finished building all the walls and pouring the concrete for the walls? From what I understand, the wall needs to be filled with concrete after 6 layers and the placement of reinforcement wires. If you want a wall of about 2.5 meters high, this needs to be done in 2 parts. I am curious how that went because you write that skilled workers are needed to fill the walls with concrete. Could or were you allowed to help with that yourself or did this have to be done by the men who brought the concrete? Did you also make a cellar or crawl space under your house or did you make a concrete slab with reinforcement wires on the ground and start from there? Does the architect still come to see you regularly to see if everything is going according to the rules and the drawing? I am curious how far you are now and how the construction is going. Maybe a lot of questions, but take the time to answer them at your leisure. Good luck with the building of your home and I look forward to your next message on movetocrete. Good luck! Kind regards, Ron