MrtnBuilder

Thank you all for your time and help. If anyone has any other ideas on how to solve this problem, I'd be very grateful. I'm concerned about whether it's even possible to combine several hipped roofs into one on such a rectangular structure?

After analyzing the height and the required eaves, it turns out that the first floor must be at least 300 centimeters high so that the straight eaves don't overlap the 220-centimeter-high window. A straight eave is created by extending the truss beyond the face of the wall. In this case, this is not possible because it further increases the building's height. Assuming the eaves extend from the truss rafter, we need to lower the rafter by over 60 cm to achieve a straight eave of 100 centimeters. This, assuming the windows are 220 centimeters high, creates a room over 280 centimeters high without any floor finishes. In this situation, constructing a truss ceiling won't help either. The only solution that might help is a multi-pitched roof consisting of several hipped roofs. A flat roof is also possible, but I want to avoid this due to the cost and complexity of the structure. The roof eaves can be created by extending the lower chord of the truss in front of the wall by a specific length, but this is only possible in this situation if the roof can be created by combining several hipped roofs into one, as this will allow for additional height to extend the eaves in a straight line.

Regarding the truss system, if it would help the building's height, it might be worth considering. Placing the trusses closer together might allow for the elimination of some of the beams supporting the ceiling, but wouldn't that drastically increase the budget? Regarding the roof overhang, the building authorities have planned for a 100 centimeter overhang. project.pdf

I was thinking about a solution: a truss ceiling or something similar on the ground floor, which would allow for MEP installations to be carried without lowering the ceiling by as much as 20 centimeters. The problem, unfortunately, is the span of the rooms, which requires supporting beams, which unfortunately have large cross-sections and require the construction of a structure, drastically increasing the height of the rooms. If I could eliminate the need for additional beams supporting the ceiling, perhaps I could keep within the building's height. On the first floor, the solution is more complicated because I can't move the MEP installations to the attic. The city's administrative decision only allows for two full floors, so with this assumption, it's impossible to have an attic above the second floor. The situation is further complicated because the city requires a wide roof overhang. At a height of 265 centimeters, the eaves on the second floor are so long that they overlap the windows.

I'm more worried about the cost of production, unfortunately in our country flat roofs or those with a low slope are expensive due to lack of knowledge and fear of leakage problems, there are few qualified companies in this field, so the price is high.

Thank you. Maybe we can do something about it to build this building. Tomorrow I'll call a few companies and ask if they produce or know if it's possible to order such trusses anywhere in Poland. Thank you again for your help; I was losing hope that anything could be done about the height of the building

I had no idea something like this existed. I wonder if they manufacture it in Poland and if anyone builds roofs on such trusses. I've contacted several companies in Poland, but no one has presented me with such a solution. Regarding the flat top of these trusses, how is it treated to prevent water from getting in? However, it's a part with a smaller slope, so it probably requires special solutions. I don't know how the office will react. In this case, wouldn't they consider the roof to be without an angle or not sloping? I don't know if they'll consider the roof to be flat on less than 50% of the total surface area.

We don't need access to the roof from the inside. I'm more interested in whether it's possible to combine it with a hipped roof and how to do it correctly without sacrificing the height of the rooms underneath. In Poland, flat roofs are among the more expensive roofs due to the lack of knowledge and fear of installing this solution. But in my situation, where the maximum building height is fixed, this is probably the only possible solution?

The administration allows a maximum of two floors in a building, so if we already have two floors, even the side part of the mansard roof is unfortunately counted as a roof. Unfortunately, in Poland, such situations are not easily resolved by the authorities. Our officials usually don't help the investor, quite the opposite. In Poland, to obtain a building permit, you must submit three volumes of documents, each usually over 100 pages long, and the wait for a decision often exceeds a year. In this situation, I have no other ideas for this roof; I don't think I can simply build this house. I tried to combine several hipped roofs in Revit to reduce the final ridge height, but I don't know how to combine them properly, I don't even know if it's possible to combine such roofs with a rectangular shape.

I was thinking about a mansard roof, but from what I've read, the first part of a mansard roof has a high pitch, often 50-60 degrees, and unfortunately, in my case, only a pitched roof with a pitch of 30-45 degrees is permitted. Does a mansard roof that only covers this range make sense? Is it even possible to create such a roof with only this pitch? The building authorities also state that flat roofs with pitches of up to 10 degrees are permitted, but they can be used on a maximum of 50% of the roof surface. Unfortunately, the problem with this roof is that I don't know how I could connect it to a hipped roof. In this case, the hipped roof wall would have to be higher to extend the membrane from the flat roof to the hipped roof wall. In this situation, would the height of the rooms above the hipped roof have to be even greater? Because if the flat roof is lower, there will again be a problem with the height of the rooms under this roof

In this difficult situation, is there any other option to divide this hipped roof into several smaller sections, which would allow for a lower height to the ridge? Unless dividing the roof would require the roof to be constructed individually, rather than using prefabricated trusses? In that case, I'm not sure it makes sense to do it at all, as the roof would be extremely expensive if the prefabricated trusses had to be abandoned

That's exactly what they came up with, which isn't very smart because the foundation should be slightly higher. In my case, the ground is sandy, so it's only 10 centimeters lower than the entrance to the building, but there will also be a terrace on the ground, so the design shows that the ground is level with the entrance to the building, therefore the ground and the entrance to the building are at the same height.

The plan I attached at the beginning included truss beams. Unfortunately, intermediate beams supporting the ceiling must run beneath these beams (these are the beams shown on the plan as dashed lines), so I'm not sure if it makes sense to do this, since I'll have to lower the ceiling anyway to accommodate the beams supporting the trusses. Another option was to place the supporting beams directly into the truss, but in that case, it would block the access to the utilities. I don't know what to do in this situation. After the company stole my money, I'm left to my own devices and don't know how to handle all this. I encounter problems with every solution. I'm starting to doubt whether this building can even be built given the 950-centimeter maximum height

Unfortunately, in Poland, the building height is measured from the lowest point of the building entrance to the roof ridge, including the roof finishing layers. Regarding the roof height, assuming I'm 30-40 centimeters short, I would have to lower both rooms by 20 centimeters. Unfortunately, I don't know why, but I have a ceiling joist in every significant place where ventilation ducts could be passed through, so after talking to the contractors, they said I would need to lower the ceiling. It's also possible that sewage pipes would be required in some places in the ceiling, so the room height is such that we don't have to worry about the height of the building and the rooms. Regarding the sewage system, it's possible that a ceiling passage will be required because the design was changed after the sewage system and foundation slab were installed. Unfortunately, we had to terminate the contract with the company that was supposed to build the building due to constant delays. They then stole the money we paid for the materials and fled the construction site. We had to change the design to be able to financially continue the investment, hence the extra height in the rooms.

the height of the rooms is 290 centimeters because we intend to install a mechanical ventilation system and install beams in the suspended ceilings, after lowering 20 centimeters for the installation, there will be 270 centimeters of clear height in each room.