Building Efficiency Factor vs Ratio?
Upsilon Architects is assembling a proposed construction budget. Construction costs are $350 per gross square foot, and the city has provided them with the following guidance for the interior spaces of the new regional community center:
 If 1 Floor: Use 1.0 cost multiplier
 If 2 Floors: Use 1.1 cost multiplier
 If 3 Floors: Use 1.2 cost multiplier
The city has decided on the following supplemental space requirements:
 Community Health Center: 3,500 nsf
 Administration Suite: 2,400 nsf
 Multipurpose Spaces: 8,900 nsf
 Maximum area per floor: 9,500 gsf
What is the construction budget for the interior spaces?
$ _______
CORRECT RESPONSE
$6,965,000
CALCULATIONS
1. Determine gross floor areas:
 Entry Lobby: 600 gsf
 Community Health Center: 3,500 nsf x 1.25 (nettogross factor) = 4,375 gsf
 Administration Suite: 2,400 nsf x 1.20 (nettogross factor) = 2,880 gsf
 Multipurpose Spaces: 8,900 x 1.15 (nettogross factor) = 10,235 gsf
2. Calculate sum of gross floor areas: 600 gsf + 4,375 gsf + 2,880 gsf + 10,235 gsf = 18,090 gsf
3. Calculate number of floors: 18,090 / 9,500 = 1.9 floors = 2 floors
4. Calculate construction cost: 18,090 gsf x $350 = $6,331,500
5. Calculate floor cost multiplier: $6,331,500 x 1.1 (cost multiplier for a twofloor community center) = $6,964,650
CASE STUDY RESOURCES USED
Scenario
Client Space Requirements

Divyang,
Sure thing! it took me a while to figure it out. Efficiency factor is different than efficiency ratio.
The factor is 25% which means the gross square footage is the net + 25% of the net.
that's why they multiplied 1.25 to get the gross.
My understanding is the factor is gross/net
and the ratio is net/gross.
thats why
 Community Health Center: 3,500 nsf x 1.25 (nettogross factor) = 4,375 gsf
4375/3500 = 1.25 building efficiency factor
and
3500/4375 = 80% building efficiency ratio
Please sign in to leave a comment.
Comments
4 comments