I am a student and am currently taking a studio where our brief constrains us to a 12 story building on a lot in NYC, even though the allowable FAR of the site would enable a much larger building. The reason is apparently because of the cost of construction—we were told that going over 12 stories in height (steel construction) becomes extremely cost prohibitive for this hypothetical client and project. The program is cultural in nature.
Does anyone have a more technical answer for why this threshold exists? Do you need to create more robust foundations or something? Could this ever be compensated for by spec'ing lower cost materials, for example, or is the cost usually way out of the ballpark and can't be compensated for elsewhere in the budget?
Thanks in advance!
awaiting_deletion
Sep 13, 15 5:45 pm
125 feet is when certain things in code change with regard to type of egress stairs, mechanical ventilation, etc.......construction wise not really. sure foundations but that has also to with soils etc....
gruen
Sep 14, 15 12:58 pm
I'm not sure why they chose 12 stories for cost and structural reasons. It's a tall building and the incremental cost to go to 13 or 14 stories shouldn't affect it.
They may be thinking about costs for water supply and HVAC. Generally water will go up 6 stories, then need to be pumped higher. Lots of times we'll put a mechanical floor at every 12th or 13th floor and pump water up and down, and HVAC up and down too.
In your building, you might make the 6th or 7th floor be mechanical, or partly mechanical. You could also make the top floor and basement be mechanical.
At the end of the day, your instructor gave you a requirement and it's up to you to accept it or to challenge it. If you want to challenge it, then you need to drill into the reasons why a building is what it is at different heights. This will require reading the building code closely, and possibly discussing it with a professional architect, structural engineer, HVAC engineer, plumbing engineer and fire protection engineer.
In terms of your question about cost and cutting costs elsewhere - you're not really going to be able to bring down the structural costs by cutting finishes, for example. The building will be steel framed, and probably have a concrete core for the elevators and services.
awaiting_deletion
Sep 14, 15 3:41 pm
Site Safety requirements change at certain heights as well....but as Gruen said,go by instructor. NYC is very complicated so there is never a straight answer ever.
I am a student and am currently taking a studio where our brief constrains us to a 12 story building on a lot in NYC, even though the allowable FAR of the site would enable a much larger building. The reason is apparently because of the cost of construction—we were told that going over 12 stories in height (steel construction) becomes extremely cost prohibitive for this hypothetical client and project. The program is cultural in nature.
Does anyone have a more technical answer for why this threshold exists? Do you need to create more robust foundations or something? Could this ever be compensated for by spec'ing lower cost materials, for example, or is the cost usually way out of the ballpark and can't be compensated for elsewhere in the budget?
Thanks in advance!
125 feet is when certain things in code change with regard to type of egress stairs, mechanical ventilation, etc.......construction wise not really. sure foundations but that has also to with soils etc....
I'm not sure why they chose 12 stories for cost and structural reasons. It's a tall building and the incremental cost to go to 13 or 14 stories shouldn't affect it.
They may be thinking about costs for water supply and HVAC. Generally water will go up 6 stories, then need to be pumped higher. Lots of times we'll put a mechanical floor at every 12th or 13th floor and pump water up and down, and HVAC up and down too.
In your building, you might make the 6th or 7th floor be mechanical, or partly mechanical. You could also make the top floor and basement be mechanical.
At the end of the day, your instructor gave you a requirement and it's up to you to accept it or to challenge it. If you want to challenge it, then you need to drill into the reasons why a building is what it is at different heights. This will require reading the building code closely, and possibly discussing it with a professional architect, structural engineer, HVAC engineer, plumbing engineer and fire protection engineer.
In terms of your question about cost and cutting costs elsewhere - you're not really going to be able to bring down the structural costs by cutting finishes, for example. The building will be steel framed, and probably have a concrete core for the elevators and services.
Site Safety requirements change at certain heights as well....but as Gruen said,go by instructor. NYC is very complicated so there is never a straight answer ever.