Hello, I’m new to the forum and my name is Ingo. I have just purchased an apartment that is about 40 years old and in need of significant renovation. Among other things, I would like to enlarge the bathroom, which would require moving some walls inside the apartment. According to the original building plans, the walls are marked as LW, which likely stands for lightweight wall. In reality, these seem to be 10 or 12.5cm (4 or 5 inches) thick Ytong walls.
Is it possible to simply remove such a wall, or would the concrete ceiling risk collapsing? Do I need to support anything?
What is the best method to build or fix the new wall? I would probably use 10cm (4 inches) Ytong and instead of plastering, cover it with drywall panels (I’m not skilled at plastering, but I have installed drywall panels before at a friend’s place).
Best regards,
Ingo
Is it possible to simply remove such a wall, or would the concrete ceiling risk collapsing? Do I need to support anything?
What is the best method to build or fix the new wall? I would probably use 10cm (4 inches) Ytong and instead of plastering, cover it with drywall panels (I’m not skilled at plastering, but I have installed drywall panels before at a friend’s place).
Best regards,
Ingo
B
Bauexperte26 Mar 2014 11:41Hello Ingo,
What radiator recesses do
In past decades, architects liked to place radiators in recesses under windows, if desired. Hiding the radiators makes a room appear larger and with smooth surfaces. Saving heating energy was not a priority then. Our generation now faces the challenge of integrating the existing building fabric to meet today’s demands as best as possible. Because the wall in radiator niches is thinner than the rest of the wall, it cools down more at that spot. A significantly cooled part in a building results in a thermal bridge. At this spot, condensation forms first upon reaching the dew point, with all its negative consequences. Only the heat from the radiator prevents this from happening. This gives the impression that the radiator needs more energy because it sits in a niche. That is partly true, as heat does escape to the outside there. However, the amount of energy saved by insulating radiator recesses is generally overestimated. You should not overdo such measures to keep them cost-effective. Additionally, incorrect insulation can even promote condensation and cause even more damage overall.
Which insulation makes sense
External insulation is always preferred but cannot be implemented everywhere. That is why many manufacturers promote more or less well-designed internal insulation systems. The most common solution is reflective foil. It is cheap but does not achieve real success. With insulation on the inside, the wall cools more, and the dew point moves further inward. Once warm air reaches this point, condensation and soon mold will develop. The most radical solution would be to completely wall up the radiator recesses and mount the radiators on the flat wall. If that is not possible, you can use a vapour-permeable mineral insulation fixed over the entire surface to the wall. Don’t forget to insulate the reveals as well, because moisture from the other, cooler surfaces behind the insulation may otherwise get in. Keep at least a 5cm (2 inch) gap behind the radiator to avoid hindering convection. Make sure the exterior wall is dry, and no moisture penetrates from outside during driving rain. If you use a vapor barrier, it must be perfectly airtight, which is often difficult to achieve.
So your chimney sweep is the worst possible consultant in this case. Which further proves that external expertise—expertise on site—must be obtained.
Best regards, Bauexperte
Ingo.M schrieb:I see you more in the position of providing details – if you want information on the "how," then you need to give the users here as much detailed input as possible.
No one has asked me here for exact parameters yet,
Ingo.M schrieb:I have been doing my job long enough to read between the lines.
the apartment was certainly not a bargain, and I didn’t ask for “cheap” answers here, you are reading something into that yourself,
Ingo.M schrieb:The drainage will most likely have to be modified, since you are changing the flow volume in the existing wastewater pipes. Whether the wall can be moved or not, nobody can answer who does not know the multifamily building you live in. Is it a structural wall, meaning does it have a load-bearing function? Since you don’t have the structural analysis, it makes sense that you will need to consult a structural engineer.
I understand that I still need to invest about 20-25k€ in the apartment, of course, I would prefer to do some work myself, which generally saves money, but before contacting tradespeople, I’d like to inform myself a bit in advance. The bathroom wall should be moved by about 40cm (16 inches); there is a bathroom underneath as well. The drainage must not be altered. I just want to install a larger shower and have a bit more space in front of the sink and next to the toilet.
Ingo.M schrieb:No house is like any other! No alteration to the structure is comparable! If the architect confirms this statement in writing (in case it’s wrong; old plans sometimes have their own pitfalls and people make mistakes), then that’s fine. I don’t dare make such a remote assessment, and most other users here probably don’t either. For example, if you had mentioned right at the beginning of your post that it is a lightweight construction, you would likely have had helpful DIYers jump in.
And about the external expertise – well, I assumed that a housebuilding forum would also include professionals with the expertise you mentioned. Meanwhile, I spoke on the phone with an architect who told me that walls marked with LW in the construction drawings are generally not load-bearing, or they only support themselves. Such a statement could also have been made here by professionals in the forum.
Ingo.M schrieb:With some quick research, you could have found the reasoning yourself… E.Curb (architect) expects some initiative.
And also the answer that radiator recesses shouldn’t be insulated, without any explanation, does not really help me. My chimney sweep advised me on site exactly the opposite – the wall, brickwork plus (wood panel?), behind the radiators is only 14cm (5.5 inches) thick, and a lot of heating output would be lost to the outside. I should insulate or even completely wall up those recesses, at least that was his opinion.
What radiator recesses do
In past decades, architects liked to place radiators in recesses under windows, if desired. Hiding the radiators makes a room appear larger and with smooth surfaces. Saving heating energy was not a priority then. Our generation now faces the challenge of integrating the existing building fabric to meet today’s demands as best as possible. Because the wall in radiator niches is thinner than the rest of the wall, it cools down more at that spot. A significantly cooled part in a building results in a thermal bridge. At this spot, condensation forms first upon reaching the dew point, with all its negative consequences. Only the heat from the radiator prevents this from happening. This gives the impression that the radiator needs more energy because it sits in a niche. That is partly true, as heat does escape to the outside there. However, the amount of energy saved by insulating radiator recesses is generally overestimated. You should not overdo such measures to keep them cost-effective. Additionally, incorrect insulation can even promote condensation and cause even more damage overall.
Which insulation makes sense
External insulation is always preferred but cannot be implemented everywhere. That is why many manufacturers promote more or less well-designed internal insulation systems. The most common solution is reflective foil. It is cheap but does not achieve real success. With insulation on the inside, the wall cools more, and the dew point moves further inward. Once warm air reaches this point, condensation and soon mold will develop. The most radical solution would be to completely wall up the radiator recesses and mount the radiators on the flat wall. If that is not possible, you can use a vapour-permeable mineral insulation fixed over the entire surface to the wall. Don’t forget to insulate the reveals as well, because moisture from the other, cooler surfaces behind the insulation may otherwise get in. Keep at least a 5cm (2 inch) gap behind the radiator to avoid hindering convection. Make sure the exterior wall is dry, and no moisture penetrates from outside during driving rain. If you use a vapor barrier, it must be perfectly airtight, which is often difficult to achieve.
So your chimney sweep is the worst possible consultant in this case. Which further proves that external expertise—expertise on site—must be obtained.
Best regards, Bauexperte
Bauexperte schrieb:
Hello Ingo,
The drainage will probably need to be changed, since you are altering the existing flow rate of the current wastewater pipes. Whether the wall can be moved, no one unfamiliar with the apartment building you live in can answer that. Is it a structural wall, meaning does it have a load-bearing function? Since you don’t have the structural calculations, it’s logical that you need to consult a structural engineer.
If you had mentioned lightweight construction at the beginning of your post, you would have likely received helpful advice from fellow DIYers.
The most drastic solution would be to brick up the entire radiator recesses and install the radiators on the wall instead. Why would the flow rate of the existing wastewater pipes change? Where would the water come from? Whether I shower in an 80cm (31 inch) compact shower or a 1.2m (47 inch) shower, the water volume doesn’t change; the faucet simply doesn’t deliver more water.
I will have the wall checked again by a structural engineer on site.
In the original post, I did mention LW (lightweight wall).
Do I understand correctly that the only proper solution is to brick up the radiator recess? That wouldn’t be a problem. I had expected an expert answer like that. Because of possible mold risk (which I also read about online), I already picked out a diffusion-open material (wood fiber insulation board).
Regards, Ingo
Ingo.M schrieb:
There is really a lot going on in the forum here, 3 questions asked and after 3 days not even 1 answer, respect! What you shout into the forest is what you get back......
If your architect can assess, remotely and based only on the abbreviation LW in the drawing, whether the wall is structurally necessary, then: hats off! I would never provide structural advice without having even seen it in a photo.
Best regards
E.Curb schrieb:
You get what you give......
If your architect can determine from a remote assessment, and only by the notation LW on the drawing, whether the wall is structurally necessary, then hats off! I would never provide structural information without even having seen a photo.
Regards I had emailed the original construction drawing to the architect (a friend of a friend). After reviewing the drawing, he told me on the phone that LW (lightweight walls) are generally not load-bearing walls, which is also supported by their thickness of only 10cm (4 inches) and the Ytong material used. Furthermore, the main walls throughout the house are laid out in roughly square sections of about 5x5m (16x16 ft), which suggests that the concrete ceilings are cross-braced (whatever that means). Since I only want to move the bathroom wall by 40cm (16 inches) parallel to the exterior wall in a middle apartment, he sees no problems. Still, I will get a formal structural engineer’s assessment to be absolutely sure.
Regards, Ingo
Ingo.M schrieb:
I sent the original building plan by email to the architect (a friend of a friend). After reviewing the plan, he told me on the phone that lightweight walls (LW) are generally not load-bearing walls, which is supported by their thickness of only 10cm (4 inches) and the material used, Ytong. In addition, the main walls throughout the house are square-shaped, about 5x5m (16x16 feet), which suggests that the concrete ceilings are cross-braced (whatever that means). Since I only want to move the bathroom wall by 40 cm (16 inches) parallel to the exterior wall in a middle apartment, he sees no problems with this. However, I will still consult an official structural engineer for confirmation.
Best regards, IngoI have to admit... I have very little knowledge about this topic; I am a homeowner, like many here... but you yourself say: ...generally... and ...which suggests... I would describe a 100% certain answer differently. These are remote assessments.
Similar topics