I want to put an observatory on the roof of the building, I m afraid it will be crushed. Please help

First of all, I envy your observatory project, this is a dream I've had since I was a child, but I haven't been able to achieve it. Hehe... Okay, let's talk about some personal opinions about your plan.

Here's a summary of what you said:

1) The prefabricated hollow slab roof cannot be constructed according to the human roof.

2) Load-bearing system of brick-concrete structure.

1. First of all, it is not recommended that you use a concrete base, and your observatory is only 200kg, but I calculated that your base weighs tons of weight. Moreover, the diameter is only not supported on the load-bearing wall at the bottom, so it will be problematic to say that it is done.

2. According to the prefabricated hollow slab used before, the weight of 200kg is no problem (plus the weight of 80kg observer), if you want to be safer, it is best to place the observatory above the wall (the load-bearing wall of the 6-story building, you can find a knowledgeable person to help you take a look), there is no problem.

3. Waterproofing is a big problem, and the linoleum has been diluted at present, because the anti-aging resistance is not enough. It is estimated that the house of 85 years, the linoleum is not broken, it is almost the same, get you an observatory, and then you have nothing to step on it, and it is not normal to not leak. The recommendations are as follows:

1) At the place where the observatory is placed, the passage from the roof entrance to the observatory, the observation and standing part of the observatory... These places are covered with waterproof materials (linoleum is the cheapest, let's use this, as long as you can buy it) (full of asphalt) for waterproof strengthening.

2) After the waterproofing of the above parts is strengthened, some lightweight plate materials are used to lay them, so that the waterproof layer is not damaged when walking and standing (it is best to lay with high-density polyethylene or other hard plastic plates, and if you can't find it, you can buy some children's mats (that is, the kind of square, the edge is a zigzag joint, elastic plastic mat), try to buy some of the thicker, and then glue it to the roof with special floor glue)).

3) If the observatory is to be fixed, it is best to find a lightweight engineering plastic chassis to fix it. I really can't find it, if you have to fix it on the roof, you can only seal and irrigate the installation bolts with waterproof ointment after fixing, if you don't do it well, it will leak.

A 200kg observatory, placed on a round platform with a diameter, adds 40kg per square meter, i.e.

Now the cast-in-place floor slabs are fine, and the old-fashioned prefabricated slabs I think are enough to choke.

For the sake of my friend who is an astronomy enthusiast, I would like to add another explanation. The distant starry sky is destined to be the destination of the vast majority of us.

1.What is the size of your observatory chassis? The first thing to do is to make sure that the old floor slabs will not collapse, otherwise nothing else will be possible.

Is your prefabricated concrete chassis suspended underneath, or is there an original wall?

2.The original waterproof must be destroyed, and the original waterproof linoleum can be lifted during the specific construction, and the original linoleum and the contact position of the concrete chassis should be chamfered during construction.

3.After solving the above first problem, I will tell you how to configure the concrete by hand.