Basement Carpark on sloping site.

[Nikolaos]

Just wondering, how a sloping site affects the feasibility and cost of a basement carpark.

Specifically, if a site has a slight slope downhill from the front of the block to the back, how can you "calculate" what the ground level is. From my understanding, a basement carpark can protrude above ground by up to 1 metre from ground level. Would you just take the median level of the block ? In this case, quite a large chunk of the basement carpark would be mostly above ground, toward the rear of the block.

Also, would such a site mean it's cheaper because there is less excavation required ?

 

[RPI]

Height above depends on the Council. 1m is common, 1.25m is also around. Sometimes measurement is to the underside of the basement ceiling, sometimes it is to the top of the slab of the ground floor.

Natural ground level is taken at every single point on the block.

Water, drainage and overland flow issues need to be thought of on sloping blocks also. Sloping up from the road can be a good thing because you can excavate and drive straight in off the road while having lower levels above NGL. It is quite site specific.

If you are happy to PM me the site address I will make some comments back through here sans identifying info.

 

[Tools]

Recently built a basement where the block had 2m fall from front to back. It meant that the we were chasing the fall down the ramp and the ramp didn't hit the basement until it was well towards the back of the block, but it did work. Because of the fall the basement ended up 4.5m deep at the front.

Tools