4. Errors in the number of materials

Example:

The project provides for the insulation of the facade with a 140 mm thick insulation: an inner layer of 100 mm and an outer layer of 40 mm. The total scope of works is about 2000 sq.m. Those. the total amount of insulation will be: 2000 sq.m. x 0.14 m = 280 cubic meters . The estimate turned out to indicate the volume of insulation 380 cubic meters , i.e. with an area of 2000 sq.m. its thickness should be 190 mm, which is 50 mm. more than design thickness. At the same time , from 2000 sq.m. the volume of excess insulation amounted to 100 cubic meters . So someone's mistake reduced the cost of work and materials by about 100 cubic meters . x 8000 rub. = 800,000 rubles, and zeroed out the profit.

Provided that the brackets of the ventilated facade have already been mounted according to the project with a projection of 200 mm. from the wall, it was no longer possible to mount an extra insulation, so the customer terminated the contract for the cost of the insulation mistakenly included in the estimate.

Recommendations:

Absolutely always compare the design data with the estimate before deciding to conclude a contract.

3.2. Errors in project documentation – again losses

The attachment points of any structures have not been worked out

Next, we will talk about the most revealing errors in projects. An error of such a plan may be made in the project: the attachment points of any structures are not worked out, or they are made with an error.

Example:

Once we made a hinged ventilated facade on a two-story building, lined with hollow bricks of the “boar” type. But the designers did not notice this …

For fastening the brackets of the ventilated facade, they provided for the use of chemical anchors. According to the project, a chemical anchor was laid, 100 mm long. The technical supervision of the customer warned that we should use only such an anchor – and nothing else, because. the project has passed the state examination, and a step away from this requirement for us is execution.

But in fact, it was impossible to use such fasteners, because the wall of the brick is very thin (10-15 mm) and practically the anchor only holds on to it, because the brick inside is completely empty, as in the figure – this is the old Soviet brick “Kabanchik”, which is already have not been produced for a long time.

Yes, this project passed the state examination , it was accompanied by acts of testing chemical anchors for pull-out, which supposedly had to securely fix the brackets on this particular building, but nevertheless, this is what happened.

When performing facade work, it is always necessary to test specific anchors for pull-out from a particular wall or object, which must be confirmed by test reports. Accordingly, we called a testing laboratory to the site, which is very common with manufacturers or suppliers of fasteners. Tested chemical anchors. None of the 5 or 6 attempts to confirm their suitability was successful – the brick walls broke under the most minimal (up to 150-200 kg.) Loads.

When asked how the same laboratory (by the way, a world-famous manufacturer, I’ll regret their reputation …) gave the designers a conclusion that chemical anchors of such a length can be used on this object, the answer was something like this : “We don’t know, a person who we have this act issued, it no longer works for us … ”. I repeat, the project with this fastener passed the state examination .

At the same time, we also tested conventional facade anchors with a longer length – 250 mm, which successfully passed the tests, because. they were fixed in ordinary masonry, which followed the facing hollow brick. Having received new test reports, we refuted the design solution, for the third time I repeat, which passed the state examination , and received permission from the customer to use extended length conventional anchors. Question substitutions one anchor to another was also affected by an increase in the cost of fasteners, but with respect to other aspects, nevertheless, this allowed us to get out of the situation at relatively low costs.

However, there were some consequences:

1. Due to carrying out all the tests and agreeing to replace the anchors, a week of time was spent, which led to a delay in the completion of work for this period.

2. For the delay in obligations for this week, the customer (and the contract was state-owned) first presented us with a penalty, although in fact he was to blame. In such situations, government customers never accepted the argument that the time it took to correct the documentation was not our fault, but their own. It is not customary for them, otherwise the performers (technical supervision, department heads, etc.) will then receive a cap for violating the deadlines for carrying out work and failing to take action against contractors. After refusing to pay the penalty, the customer sued us and sued her.

3. We used more expensive anchors, no one compensated us for the difference in price, again because there is an estimate approved in the budget – please be kind enough to fit into it. This is called “replacement without increasing the value of the contract”. Although the increase in the cost of fasteners was about 20%.

Prevention measures.

1. Extremely vigilantly compare not only the estimate with the project, but also the project with the real object.

2. Be sure to correspond and notify the customer in writing about the identified errors and inconsistencies in the design and estimate documentation, draw up acts for all, including commission inspection acts. In the future, this can help not only to make changes to the project documentation correctly, but also to justify the change in the cost of work.

3. Carefully read the contract, sometimes it provides for the possibility of an increase in the cost of work or materials upon bilateral agreement with the customer, but as a rule, such an increase is limited to an amount up to 10 or 15 % of the total contract value.

metal weight

Profit can be lost even where you do not expect it at all.

Example:

We had one object where, among other things, we had to make porches or canopies over the entrances to the building. We had an estimate, which included the amount of metal needed for the installation of the porches in tons, and the project did not contain a word about how these porches should look, no diagrams or sketches. If I'm not mistaken, the estimate was about 300 kg. metal without specifying its type, dimensions, profile and thickness. In the estimate, this metal was listed as processed metal, that is, as finished metal products, which immediately increases their cost, probably twice as much as the cost of pure metal. Complete lack of clarity on how to do the job…

The technical supervision explained how to be something like this: “Do it normally, so that it is reliable and beautiful enough, but without frills …”

We looked at how this is usually done at other objects, figured out what metal would be needed, its thickness, sketched out how it would all look like, figured out that snow could fall on the visors from the roof … It seems everything turned out fine on paper. We bought metal, welded spatial frames, racks, assembled everything, painted it. We are waiting for acceptance by the construction supervisor .

A representative of technical supervision came, measured each element of our porches, measured the thickness of each of their elements. In general, I calculated the real weight of the metal that we spent on the whole thing. In fact, it turned out to be 40 percent less … Accordingly, she said that since there is less metal, there will also be less money, and these 40% were cut out of the cost of work.

We went nuts from such a “flagrant injustice”, because the porches looked quite presentable, reliable. We did not expect this at all – we simply did not think that someone could have such an approach to the formation of technical specifications and to the acceptance of work. They conveyed their claims to the customer, explained that there was nowhere to sculpt excess metal, insisted on accepting 100% of the work … To which an absolutely logical answer followed, that we mounted exactly as much metal as we were paid for, and no matter what salary we paid workers for this work.

As a result, this money was withdrawn from us and it was useless to prove something, except that it was possible to weld this missing metal somewhere else, but it was just stupid, because. the structures were already absolutely finished, it was already unprofitable to pay for these works anew and spend time on this.

Recommendations:

If you are dealing with weight volumes and do not have a project for the execution of work, check everything in advance using a metal weight calculator or metal weight tables.

Even if you have both a project and an estimate in which the amount of material is the same, still compare, at least selectively, the weight of the metal that will be needed the most, again using the metal weight calculator or the metal weight table.

4. Why it is impossible to deviate from the design on the example of facade work. The right approach to preparing for facade work.

When a customer decides to update the facade of his building, he usually asks: “How much will it cost to mount the facade?”. Whatever the question is formulated …, such is the answer. In this review, we will figure out what questions, how and to whom to ask in order to get the right answer.

The solution of the facade issue is a series of stages that mutually influence each other, and at some point it may be necessary to revise the original plan completely.

1. Preliminary concept

First, the desired appearance and, accordingly, the materials used are determined. It is important to understand that in addition to the main cladding of the building, you will have to plan the cost of installing window slopes and ebbs. Also, the cost of installing a new parapet will come out if the roof is flat, and if you have small cornice overhangs, then they may have to be increased.

Of course, you can hire a designer to draw everything approximately or exactly for you. At this stage, no one can tell you the exact cost of the work, but only the order of numbers. Alas, this is just the beginning.

2. Coordination of the facade and its changes by the state executive authorities

For example, in Krasnoyarsk there is a procedure approved by the city administration for approving the passport of the facades of buildings and structures, with the exception of individual housing construction. Therefore, your lawyer should check the existence of such requirements for your object.

In Krasnoyarsk, as part of the documents, it is necessary to provide information on the color scheme, on the materials used, lists and layouts of additional equipment, elements and devices, architectural lighting scheme, etc.

This means that it is easier to make a project than not to do it. But in fact, the project needs to be done. Now check it out.

3. Design

3.1. Design surveys, encumbrances

When constructing the facade, we increase the overall dimensions of the building. This value can be different, from 100 mm to 700 in my memory. In addition, often in the process of facade reconstruction, the owners decide to additionally arrange canopies over the entrances to the building or even porches – accordingly, this is an indent from the building up to 2 meters. Behind the facade, the blind area can also shift.

Therefore, at the design stage, it is necessary to check whether, after the reconstruction of the facade, the violation of the red lines, the boundaries of easements and the security zones of engineering networks will not occur – otherwise, you will have to dismantle everything that you mount in such areas.

3.2. Purpose, fire safety class of the building, height of the building

The parameters indicated in the title of the paragraph affect the requirements for the materials used, the arrangement of individual components of the facade structure, and further on the cost of work and materials. As a rule, most facing materials (granite, plaster, metal and composite panels) meet such requirements, but all kinds of PVC do not. The same with insulation, mineral wool – does not burn, polystyrene foam – is limited in use. In addition, heaters have restrictions on the height of the lined structures. In general, there are enough subtleties.

3.3. Inspection of the condition of walls and suspended structures

There is no point in explaining this. It is clear that all worn-out sections of the structures will need to be restored, which is not firmly fixed – it is necessary to remount. A project for such work is necessary by definition.

3.4. Fastener testing

During the examination of the walls, the type of facade anchors and insulation fasteners used is determined. It is not always possible to use conventional anchors, and chemical ones may be required. But the choice of fasteners is made not only by calculation methods, but is confirmed by acts of laboratory tests for pull-out directly at the object. Typically, pull-out tests cost about 5 – 10 thousand rubles. plus a round-trip if the facility is a long distance away, but manufacturers can do these tests at their own expense if you express interest in continuing to purchase and use the tested fasteners from them.

3.5. Thermal calculations and choice of insulation

This is generally a very important question, because. the cost of heaters ranges from 2000 to 9000 rubles / m3 , and possibly even higher. Expanded polystyrene heaters – provide better thermal insulation, but have limitations on use, because. are not non-combustible, unlike mineral wool . A combination of less dense (“cheap”) and denser (“expensive”) insulation materials is allowed to achieve optimal thermal insulation of the walls.

Often, customers have no idea about such subtleties and make a decision “by eye” and at a price – which is fundamentally wrong.

3.6. blind area

Depending on the chosen type of facade, its installation begins either directly from the blind area, or with an indent from it by 20 mm – if a ventilated gap is needed. Therefore, before performing facade work, it must already be completed.

But there is a certain problem with the blind area – this is the state of the soil and its seasonal swelling. The condition of the soil can spoil both a single flooding of the site, and a change in the state of groundwater, showers, etc. In this case, improper performance of work on the blind area may lead to its rise.

From practice, the lifting height can be both 50 and 100 mm. Accordingly, the pressure from the blind area passes to the facade elements, crushing them like an "accordion", shifting the facade subsystem along with the cladding. As a rule, a gap is made between the profiles for thermal expansion of the metal, but it is only about 10 mm. Considering everything, in the best case, only the facade of the first floor, or its lowest part, may suffer, in the worst case, the deformation of the facade will go higher.

Therefore, the development of a project and a survey of the state of the soil in terms of the blind area during the construction of the facade are mandatory.

3.7. seismicity

The choice of facade materials, fasteners, etc. the seismicity of the area in which the object is located. Therefore, in areas with high seismic hazard, the materials used must be certified for use in such conditions, and in the event of earthquakes, they must minimize the risk of injury during failure. This also makes adjustments to the final appearance of the facade, its technology and cost.

3.8. Gaps between metal elements of the facade

Often, customers want the joints between the individual panels of the facades not to be visible and ask to make the installation without gaps. Alas, due to the thermal expansion of metals, facing materials can become unusable, deformed. Even designers forget about it, but you must remember and demand compliance with these standards.

3.9. The layout project of the profile system, cladding and individual components of the facade

Only at this design stage it is possible to see the future appearance of the facade as close to reality as possible, to see the visualization, to understand the cost of work and the need for materials.

But, now we have to wait for the decision of the supervisory authorities … And only then either correct the project, or finally start the work in accordance with the current regulations.