Weight of plantings

While I can't help you on the weight restrictions- look at it this way...if your plants are too heavy for the structure you could be on the hook for any an all damages. Water finds the path of least resistance, and once a weak point is found it could cause extensive damages. Your building is right to have over restrictive interpretations.

Right.

I've seen weight per planter not more than 150 lbs., concentrated weight not more than 50 lbs. per ft², soil not more than 30 lbs. per cubic foot, etc.

The concrete slab is not the vulnerable point. It's the waterproof membrane between the slab and top terrace surface. Also, the loose soil can gradually wash out and clog the drains, letting rainwater pool and find a way through cracks in the parapet wall.

Every NYC terrace-scaper knows how to meet the standards, so just leave it to them.

Thanks for the comments and I do understand the issues. It all makes sense. however, there is a difference between appropriate and over-restrictive. One doesn't buy a penthouse to not have plant Inge. Any examples of guidance would be very much appreciated.

NWT, do you have any recommendations for a terrace-scraper? Many thanks.

Our building had the engineer set up the guidelines based on the structure below. We listed a conservative weight because people were buying fast growing plants. They started off within the weight guidelines, but within a few years the plants grew and exceeded the guidelines. We had a few apartments with enormous terraces and they planted a lot of trees.

1. The heaviest part is the water, not the trees themselves. So use an irrigation controller, and water lightly and frequently (which is not always the pattern that keeps plants happy, especially trees).
2. Always use "potting mix", which is much lighter than soil.
3. It's not the soil that can clog drains, but the leaves, twigs, etc. that fall. So screen the drains and be sure to clean them off regularly.
4. Grow these tomatoes: Cherokee Purple, Kellogg's Breakfast, Blondekopfchen, Burbank Red Slicing, maybe Marglobe. Plus Rubel blueberries, lots of them.

What is a terrace-scraper?