How can I route storm water away from my atrium?

Question

I have an atrium in my condo that is exactly in the middle of the house. It has gutters and downspouts around it and whomever built it, just let the downspouts empty into the open courtyard of lava rock. I want to put a solid floor in the atrium and have the gutters empty somehow else. There is no possible way to empty them into an underground system, nor even an above ground one. I cannot see anyway to reroute gutters to go off another point of condo. Is there a fix for this?

Answer 1

Can you tear up the courtyard and put a leach field under it before laying down the floor, thus preserving the through-ground drainage now present?

Can you consider rain-permeable material as flooring? (Some ideas here and here, or investigate other options.)

Other than those, the only idea I've got is a sump, a pump, and run the pump's output thru basement to outside.

(Or to drain and sewers if that's legal in your area; it isn't here.)

Answer 2

If the atrium is open to the sky, then it will always receive rainwater when it rains. Therefore, enclosing the space is the only way to entirely divert rainwater away from the space.

This points to the general solution, changing the direction in which the roof system slopes (as a useful abstraction consider the roof system to include the gutters and downspouts). If you cannot change the direction of the slope and the slope is toward the atrium, then you cannot divert water away from the atrium.

What is under your control is the meaning of solid floor. Something as simple as spaced deck boards will allow the area to become useable outdoor space while still allowing the water to drain. The key idea is permeability.

Other alternatives range from replacing the lava rock with pebbles as in a Zen Garden to exotic solutions like permeable concrete, to practical compromises such as providing a solid floor over only part of the area.

My advice is to proceed so as to avoid reducing the drainage capacity of the existing system. It works, and flooding is usually not worth gaining outdoor space.

Answer 3

Is there any way you could add a pipe going through the wall, and direct it to an adequate exterior drainage spot, and then route the gutters to that pipe?

That said, if this atrium is open to the sky, redirecting the output from the gutters isn't enough if you want to add a solid floor. Where is the rainwater going to go? You'd probably need to add a roof structure of some sort.