We recently did a search for a good synopsis of the basic differences in costs and requirements for different heights/stories of apartment buildings. Finding none we decided it was time to fix that.
3 stories
Type VB construction does not require rating of the structural frame.
(Just ratings between units and corridors)
No elevator required
Ground floor accessible
NFPA13R
125/sf
4 stories
Type VA construction you need to rate ANY beam that fall under certain restrictions
Or
Type I podium with Type VB above 3 hr Floor
Elevator Required by ADA
All Floors Accessible (This means more Type B units, not that they are really changed from floor to floor)
NFPA 13R Fire Sprinkler System
150/sf
5 stories
Type III construction, 2 hr rated exterior walls (with fire retardant treated wood), and rated floors for Type IIIA
Or
Type I Podium with Type VA above 3 hr floor
Elevator Required by IBC and ADA
All Floors Accessible
NFPA 13 Fire Sprinkler System (Sprinklers in cavities)
Increased detailing for differential shrinkage of wood (Brick relief joints etc)
Increased shear wall detailing and increased structure on bottom floor
3 thoughts on “3 Story vs. 4 Story vs. 5 Story Apartments”
I have a project right now that we are bringing through the entitlement process. Currently we are planning on going 3 stories and we’re doing exterior stairs. The city would rather have us go 4 stories and bring the hallways and stairs on the interior and use an elevator. The benefit is we get more units but we have never built a project of that size and are unsure of the additional costs that will bring to project. I see in the blog it points out to add an additional 25 per sq ft for this jump. I was wondering if anyone could share more details on what causes that jump in price. Thanks
Juliane,
That is because at five stories, you have to go from type V construction to type III construction. Can still be wood frame, but it needs to be fully fire rated and therefore is very uneconomical to do. As a result, you don’t see a lot of five story wood framed buildings.
Great information. However, there is no cost per sf for the 5 story wood construction; only for the 3 and 4 story types.