ᐅ Issue with Ceiling and Floor Clearances

Hello hardworking home builders,

I reached out here a while ago about floor coverings for a luxury house I’m working on for a school project and received many helpful responses. Unlike a typical student, I didn’t hand it in a few days late but, being diligent, submitted it a full 3 months early... ;-P I wanted to use the extra time to thoroughly review my house design, and I noticed a few flaws I wanted to fix before submission. For example, when I determined the ceiling thickness, I completely forgot about the screed and floor covering and planned the stairs accordingly. It would have been a great house, just unfortunately without any flooring... +^^+ A bit embarrassing.

Starting with this “problem,” which was quickly fixed thanks to an eraser and calculator, I found more and more issues. The best part is that a solution in one area basically created a problem in another.

Here are some key details about the house:
Site coverage ratio: 0.2
Floor area ratio: 0.4
Plot size: approximately 5,000m² to 8,000m² (about 1.2 acres to 2 acres)
Maximum number of full storeys: 3
Living area without basement (which still needs to be designed): 1,169.24m² (12,580 sq ft)
3 full storeys present, 2 at 495.52m² (5,335 sq ft) each, 1 at 178.2m² (1,918 sq ft) (all external wall dimensions)
Ceiling height, ground floor: 3.00m (9.8 ft)
Ceiling height, first floor: 2.70m (8.9 ft)
Ceiling height, second floor: 2.70m (8.9 ft)
Ceiling thickness including floor covering: 0.36m (14 inches)
Stairs: riser height 0.17m (6.7 inches), tread depth 0.30m (12 inches)
Basement (planned): 608m² (6,547 sq ft) >> 38m x 16m (125 ft x 52 ft)

That’s the overview. If you need more info, please let me know. I’ll provide what I can.

Now to the main issue, which I hope I can explain clearly. The house is shaped roughly like a flattened T, sometimes called a “protruding annex.” The house will have a basement but not in the same shape—instead, the basement will be rectangular, meaning it’s larger than the house above. So far so good, until…

…the part of the basement that extends beyond the house footprint is planned to be covered with grass and plants, not just lawn. To accommodate as many plants as possible, I designed the soil depth at 100cm (1m) (39 inches). From my design, the distance between the bottom of the ground floor and the ceiling of the basement is about 150cm (59 inches). From what I have read online, the floor slab between basement (KG / cellar) and ground floor (EG / first floor) is assigned about 50cm (20 inches) plus screed and floor covering, totaling around 65cm to 70cm (26 to 28 inches). That still leaves about 80cm to 85cm (31 to 33 inches) of empty space, which shouldn’t be there.

Do you have any ideas on how to solve this?

Thanks in advance for your great help, and I look forward to your replies.

Best regards,

C.

Take a simple approach: How much soil do you really need for plants and grass?
Usually, 30cm (12 inches) is sufficient for planting grass, roses, and similar plants.
The bigger issue is: Where will the water go when it rains? How do you drain water along the perimeter of the basement wall to prevent waterlogging?
If you have the freedom to plan: Consider marking an area with gravel or crushed stone using different colors in your plan and place potted plants there. If done well, it can look very elegant.

Would a glass roof for the basement be an alternative?

Rather less... The sections in question are relatively large. In addition, one part is directly above the basement garage... Therefore, a glass roof is actually not an alternative.

The areas measure 7.40 m x 7.60 m (24.3 ft x 24.9 ft) on both sides. Actually, that is too large for me to cover with gravel there...