ᐅ Length / Slope of Driveway to Garage / Carport

Hello,

I have a question regarding the driveway to the garage. Our plot has a slight slope, so the garage cannot be built at street level and a driveway is needed. I have created a sketch for this purpose (see attachment). The question is basically straightforward: How long should the driveway be? I read online that the slope should not exceed 15%, and if I plan just under 15%, I get a driveway length of 7 m (total elevation change of 1 meter (3.3 feet)). This would be ideal for us because then the 4 m (13 feet) area in front of the house would be level, with the driveway leading down the side to the garage below. Our architect advised against this solution and recommended letting the driveway start from the street level or reach all the way to the street. However, that would be impractical for the entire courtyard.

I find it difficult to assess whether “our” solution is practical.

I outlined my thoughts and based my calculations on the elevation plan. With a garage height of 2.7 m (8.9 feet), I calculated a floor slab elevation of 204.5 m above sea level. I would plan the driveway with a width of 3 m (10 feet), leaving 3.5 m (11.5 feet) to the house. The maximum elevation difference would be 1 m (3.3 feet), where it would be possible to slope the terrain over 0.5 m (1.6 feet) and build a small retaining wall. The main question remains: How long does the driveway need to be? What is practical?

Thank you!

We have planned an elevation change of 0.95m (3.1 feet) over a 6.5m (21.3 feet) driveway. I modeled this in a CAD program, and every standard car can just barely manage it without scraping. So definitely no more than that. This results in an almost 15% gradient.

Bauenaberwie schrieb:

We planned a height difference of 0.95m (3.1 feet) over a 6.5m (21.3 feet) driveway. I simulated this using a CAD program, and any normal car can just manage it without scraping. Definitely not more than that. That comes to almost 15%.

Thank you, that matches my calculation as well. Is the slope flattened at the top and bottom? Do you need to drive in especially slowly to avoid scraping, or is a normal speed fine?

Purely from the CAD model, a rounding is better but not necessary. In the model, no settling or similar effects were visible when moving up and down.

Bauenaberwie schrieb:

Purely from the CAD model, a rounding is better but not necessary. When moving up and down, no signs of setting or similar were visible in the model.

Great, I would love to have a model like that too, but the basic conditions are similar here. How did you build the wall? L-shaped blocks?

What advantage do you see in having a perfectly level surface at the start? If I were you, I would make it as flat as possible and therefore use the entire length.