ᐅ What is the required slope for a driveway and parking space?

Hello everyone,

Please take a look at the following height measurements. Is there enough slope planned towards the street? We want to pave the areas! (No eco-friendly paving!)

1.)
Length of the driveway to the garage: 8 m (26 feet)
Finished height of the garage floor: 40.86 m (134.1 feet) above sea level
Height of the street: 40.78 m (134 feet) above sea level
(DIFFERENCE ONLY 8 cm (3 inches)!!)

2.)
Length of the parking space to the street: 6 m (20 feet)
Height of the side of the parking space away from the street: 40.86 m (134.1 feet) above sea level
Height of the street at the parking space: 40.81 m (134 feet) above sea level
(DIFFERENCE ONLY 5 cm (2 inches)!!)

Isn't there anyone familiar with this? So far, I have always read that most people take 2%. Does that mean that 1% or 0.5% is not possible? Or that it is not recommended?

Who has experience with this?

Nobody will stop you from doing less. Is the slope away from the garage or towards the garage? How is the drainage planned? If you place it somewhere 5m (16 feet) or 6m (20 feet) away from the garage, achieving a 2% gradient is easily possible.

I don’t see the problem.

toxicmolotow schrieb:
How is the drainage planned? If you place it about 5m or 6m (16 or 20 feet) away from the garage, achieving a 2% slope should be easy.

We need to allow the rainwater on the property to infiltrate into a soakaway system. The plan is to direct the water at the driveway to the garage and the parking area each into a drain at the transition to the street, which then leads to the soakaway.

Having a drain in the middle of the site is not something we find very appealing.

toxicmolotow schrieb:
No one will stop you from using a smaller slope. Is the slope going away from or towards the garage?

I’m not looking for anyone to stop me from doing something. Rather, I’m looking for someone who knows what is practically feasible. In other words, would slopes of 0.5%, 1%, or 1.5% also be sufficient? Or would that be problematic? Honestly, I have no expertise in this area. However, we do want to have the drains located at the end of the garage driveway, basically at the transition to the street.

Thank you very much for your help!

Does anyone happen to work in this field and can tell me more about it?

From this, I understand that the street is the lowest point.

A practical solution (and this is even available with a concealed, attractive, and paved 1cm (0.4 inch) channel) would be to slope 2m (6.5 feet) from the street at 2%, then install the channel, and then raise it again by 12cm (4.7 inches) over the next 6m (19.7 feet). This way, you maintain a 2% slope everywhere.

The problem with a shallower slope is that water won't drain well, and depending on the wind direction, it could push water into the garage. Alternatively, the garage floor would need to be raised by 4cm (1.6 inches).

You won’t be at risk with less slope; the water will just stay longer where it fell, especially during heavy rainfall.