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Conceptual errors and thermal bridges - yard in Antwerp
PXL_20201203_073501457.MP (1)

Decoupling of new outer walls with the common walls (Koudebruggen)

After my advice to disconnect walls and avoid thermal bridges, the engineer writes the following:

"I read in the report of the developer's expert that the new rear wall must be disconnected from the right-hand partition wall. I strongly advise against this, as this wall also provides the transverse stability of the partition wall. I do not accept any any form of damage claim related to construction damage if these walls are not anchored to each other.


The engineer is taking his position here and I understand his concern.


" I strongly advise against this as this wall also provides the transverse stability of the partition wall ".


I also hear from him where his concern is most directed, and this on the first floor on the common wall of the neighbor on the right. Here he states that there could be a bend at the common wall in the direction of insulation and new wall because it could press the insulation!




















In this I replied that there are sufficient solutions to counteract this and still disconnect the wall. He does not speak about the insulation itself and decoupling, it is more about the transverse stability of the chemical wall!


I declare


What has been done now?


1) Quickbuild is not bound in the common wall!

2) Would steel bars have been placed in the common wall and between new masonry? How this was done and to

   how many layers is not clear to me, and is this done with chemical anchor and correct?


So because the new fast-build is actually just built against it and is only fixed with these anchors, I don't see the problem in disconnecting this wall. It is also not a major destructive intervention to adjust this!

I'll give you some examples:

Use of the correct flameproof insulation as a solution. After my research there are certainly two possibilities.


1) XPS insulation boards: with the following properties - XPS stands for extruded polystyrene. XPS is also called polystyrene rigid foam.


What is it used for?  


XPS insulation boards are often used to insulate basements, cavity walls, interior walls, exterior walls, floors and roofs because they are pressure-resistant! are available in different thickness.



















2) Foam glass blocks = cellular glass is a light, hard and durable insulating material and consists of millions of hermetically sealed

   glass cells. Foamglas insulation offers an exceptional combination of properties including non-combustibility, very high

   compressive strength guaranteed water and vapor tightness and long lasting thermal performance.

























Since these foam glass blocks are not cheap, one could have used this on the first floor, and this 5 cm thick so that it fits nicely with insulation that one would place inside the common wall.


One could have used XPS on the ground floor.

In practical terms, a cold bridge (thermal bridge) is a connection in a construction in which the "cold" is conducted from the outside to the inside of the construction. The consequence of this thermal bridge is, in addition to heat loss, especially condensation of water vapor in the warm air, which sometimes causes mold and odor nuisance. In the summer it is the other way around, because then warm air can enter through the 'cold bridges'!


Can be solved perfectly with my two proposals!

After my answer to his writing, below answer from the engineer!

" I maintain my position here that the walls should not be disconnected. There are compression-resistant insulation materials that, in conjunction with anchors, can provide a thermal break while still guaranteeing the connection . Your expert's proposal with foam glass is a good example of this , However, this is a very expensive solution for the thermal break. This expert's proposal is possible from a stability point of view. "

This is not an expensive solution if you compare it with the problems that can arise afterwards, by the way if one places Perinsul during the erection of fast-build, this is only a small act to place it right against the common wall. Only the material is more expensive than other insulation, but this is only a few meters!  

The architect should have known this, but when I spoke to him about it on site, he fell out of the sky. So I consider him responsible for lack of knowledge of this.

My answer to the architect:

I stand by my position that these walls must have been disconnected, so still to be done!

Conceptual errors  when using steel beams and columns instead of concrete!

The story begins  in the plans drawn up in 1930:

Reading and understanding very old building plans " it's a must" , which is a basis for a graduate architect and must manage the necessary knowledge thereof, Incomprehensible that was not the case here, and the consequences of conceptual errors weigh heavily!

existing and new building plans!

On my closer investigation I noticed the following.


1) On the existing building plans dated. from March 21, 1930 I notice that the mean walls 28 cm or 36 cm are indicated here

   (36 cm has been crossed out) existing situation is 18 cm, as well as cesspool with partition and lid (access via outer courtyard)

   drawn within the construction area and just against the outside toilet.







































existing building plans dd. from March 21, 1930                       New plan dated. 04/11/2020

2) On the adjusted plans dated. from September 26, 1958, this house has already been renovated and is no longer mentioned!

3) On new plans dated. of 04/11/2020 the cesspool was drawn incorrectly and the mean wall thickness of 28 cm was taken from

   the existing plans from 1930.


   Also a dividing wall of 18 cm hall and sitting room / intermediate room was taken over, existing situation 10 cm .

4) Intermediate wall of the hall and sitting room/intermediate room is indicated on the old plans as 18 cm or 10 cm!

5) On the new plans dated. of 04/11/2020 the following is stated: "no destructive testing performed" You do not need

    tear down constructions to notice different things on the spot!


I declare:


a) Common walls: if you look at the common walls at the back of the house (garden), you immediately notice that the dividing wall on the left is only 18 cm instead of 28 cm! Hereby one comes to adjust the new plans "before" the works had started!

b) Also from the garden, you immediately notice a lid outside the building area that gives access to the cesspool!

c) Intermediate wall of the hall and sitting room/intermediate room: if you had looked closely at the old plans from 1930, you could notice that the

   architect of the time left two choices for the contractor, all wall thicknesses are 36/28 - 18/10 - 28/18, in the hall on site

   was it also easy to check whether it is 18 cm or 10 cm? So it's 10 cm!





















I note that the house has been examined too little or not at all on the spot and has simply used the old plans from 1930 as a yardstick, except for the cesspool because it was drawn incorrectly.

It is very clear that this had a very big impact in a later imperative change that had to be made "during" the construction works that had already started. In particular, a stability change that has the consequence that there are now columns everywhere and infills of at least 20 cm are now necessary, and this in full gyproc walls with an enormous loss of space. Before this change, the engineer had provided overlays everywhere "in" the mean 28cm walls which would have been a big difference from what we see now!

The architect writes the following in his site report, during the started work:


"Overflowed stability study: Ing. Adjusted the study so that the structure would become lighter. Here, shatter walls of 28 cm thickness have been taken into account. When checking, there is doubt whether the shatter walls have the drawn thickness of 28 cm. the plans from the archive). The study will be adjusted again, since in the absence of the 1.5 stone screed walls, the slippers cannot be carried out on them."


Of course, this determination should have been determined in advance, and this during a preliminary study before the plans are submitted to urban planning!

The architect


If the architect could "understand and understand" the old plans from 1930, and that he had made a comparison on the spot, that would have been a completely different matter. In my opinion he has in no way done a thorough study in this file, with the known consequences, and a very big disappointment for the owners, and serious additional costs. The architect did not work professionally in this, and I lack experience in such a project.


The contractor is also not exempt from this, a contractor is expected to manage the full knowledge of construction events, if he had done better and more thoroughly when visiting his site, and this in comparison with the architect's plans, he would also have had this errors in his plans.



The architect writes:

Steel girders: Laying steel girders on a common wall is feasible but also expensive
because of the risks. The entire execution of the steel was discussed with the contractor and
engineer during the first site meeting on site. In accordance with the applied
implementation determined. Here again we follow the advice of the engineer. Nor do I think that the
engineer had suggested a different version to another contractor."

Contrary to what the architect writes, the engineer had indeed developed a different version, all steel structures were indeed intended to be imposed in the common walls that the architect indicated to be 28 cm , and not 18 cm as they are now! The result is that there are now columns everywhere!


















In view of all this previous history of this house, I maintain my opinion that it would have been better to opt for concrete construction in versions than steel, then many problems regarding extra costs and loss of space due to steel columns would have been solved with it!


In the end, the architect admits in his second letter that concrete construction was indeed possible here, when I read this I almost fell off my desk chair! Much too late to get over that. He always insisted that I knew nothing about it and that my report was full of errors, gaps and discrepancies? He also asks himself whether I am experienced enough and had received an education, until the engineer confirmed my findings and did not disapprove, the architect's response is different now. I do not expect such statements from an architect who has had a solid education, I can expect that from a contractor! 🙂

His answer:

"Steel construction – concrete construction: The structure of the new rear building indeed had
concrete can be carried out."

This clearly shows how inexperienced this architect is and has too little knowledge to be able to successfully complete such a project according to the needs of the owners!

There are also quite a few questions about the architect's responsibility in this regard; In particular, the lack of regular supervision with regard to the comments, and keeping the new owners informed about matters with a significant impact on the daily use and enjoyment of this property.


The architect has an audit assignment as well as an obligation to provide assistance to the client. If he notices shortcomings during the execution of his audit assignment, he must first of all inform the client about this, in the first instance by means of site reports.


These site reports are essential so that the architect can demonstrate that he has complied with his duty of regular site inspection and that he has informed the client of the shortcomings he has identified that have been committed by the contractor and that they have corrected them.


The contractor

Here the contractor is used to always using steel structures as opposed to concrete structures because the contractor has no experience with that?  


And yet he is a general contractor?

The contractor is not exempt from this either, a contractor is expected to manage the full knowledge of construction events, if he had done better and more thoroughly before visiting his site, and this in comparison with the architect's plans, he would also have these errors in his plans also noted.

If this contractor does not have enough experience to be able to carry out these works according to the needs and assistance at the request of the owners, he should never have accepted this!


A contractor is also expected to be able to assist the architect and engineer, in order to be able to discuss his experiences in stability and construction events that he has to manage in this way with them and the owners, such as in concrete construction instead of steel, and what the impact is there. of the daily use and enjoyment of this home, anda cost!

Very sorry for this beautiful project!

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