ARCHITECTURAL | Design & Site Planning | 14 Questions (EASY-MODERATE)

A BUILDING WITH VARIOUS GENERAL RETAIL ESTABLISHMENTS

14 Questions - Difficulty Level: EASY to MODERATE)
by Raison John J. Bassig

PROJECT BRIEF:
You were commissioned by a client, who owns a 1.26-Ha. property located along a national highway in San Fernando, Pampanga, to design a building that will house various general retail establishments in the community. His lot is regularly-shaped with a 96.00-m frontage facing south along the highway, a 27.50-m RROW. All other lots adjacent to his property is still undeveloped. The whole vicinity, including his entire lot, has a constant downward slope of 5.00% from east to west.

DESIGN CRITERIA:
During your consultation with your client, you have ascertained the following preferences:

1. He prefers that the building will have ample natural light and ventilation all-around and does not want any firewalls or abutments extending to the property lines.
2. He wants the building positioned exactly in the center of his lot and have all sides of the building to be exactly equal, using the maximum dimensions as allowed by law, to reflect his advocacy of equality and fairness towards others.
3. He requires the building to be 3 storeys which will house all retail stores at only a 40% leasable area per floor (so that 45% will be for non-leasable spaces for large circulation, common areas, all open for public use and that the remaining 15% will be for utility and service areas with restricted access) and a flat roof/deck (for all utilities such as mechanical and electrical equipment that may be needed). All parking spaces will be outdoors and on-site (free parking).
4. Based on the existing stores in the locality, your client wants the units he will be leasing out inside the building to have an average floor area of 68.50 sqm per unit (no greater than 70.00 sqm per unit because most local stores might not be able to entirely use nor afford the higher rates per sqm of renting large units).
5. The desired floor-to-floor height of the building is as follows: G/F @ 1.00m above highest natural grade line of the property (in case of flooding); then, 2/F @ 4.15m above G/F; then, 3/F @ 3.85m above 2F; and lastly, Roof Deck @ 3.20m above 3F. A 2.70-m high parapet wall must be constructed around the flat roof/deck to conceal any large mechanical equipment.


6. Incremental setbacks are waived.

All answers should be based on the requirements of the National Building Code of the Philippines (PD 1096 and its 2004 IRR).

Q#1: What is the Maximum Allowable Building Footprint of your project?
a. 8,100.00 sqm
b. 10,710.00 sqm
c. 9,450.00 sqm
d. 11,002.50 sqm

Let's first define what the building parameters are based on the given description of my design problem.

Total Lot Area (TLA) = 1.26 hectares x 10,000 sqm/ha = 12,600 sqm
Lot Type = Regular Lot (Inside Lot)
Lot Frontage = 96m
Lot Depth = not given, but since regular lot, can compute by [TLA / Frontage] = 12,600 sqm / 96m = 131.25m
Road Right-of-Way (RROW) = 27.5m
Use = Retail Establishments = Group E, Division 2 = E-2 (per Sec. 701 and Table VII.1)
Zoning Classification = Commercial C-2 (per Table VII.1)
Preferred Abutments/Firewalls = None required by client
Preferred Building Dimensions = All sides equal = Square-Shaped
Number of Storeys = 3 + Roof Deck

Now, let's compute for the Maximum Allowable Building Footprint (AMBF). Side note: Remember that AMBF does NOT always mean the actual building footprint. AMBF means the maximum footprint ALLOWABLE in accordance with the code. The building footprint is the ACTUAL footprint occupied by the building based on design and client requirements, which logically, should be EQUAL TO or LESS THAN the AMBF to conform with the code.

There are several provisions in the the code to determine the basis for the AMBF. Let's look at some of them:

Based on Maximum Allowable Percentage of Site Occupancy (PSO) in Table VIII.1, we see that for COMMERCIAL 2 structures WITHOUT firewalls, the Maximum Allowable PSO is prescribed at 75% of the TLA. So,

AMBF (based on Max. PSO) = 75% x TLA = 0.75 x 12,600sqm = 9,450.00sqm

Next, we can also check the AMBF based on prescribed Setbacks for Commercial Buildings in Table VIII.3. Since the given RROW of the project is 27.5m, the setback requirements would fall under the "25.00 to 29.00 meters RROW" category in the table, where:

Prescribed Front Setback = 6m
Prescribed Side Setbacks = 3m
Prescribed Rear Setback = 3m

So, given lot dimensions of 96m (frontage) x 131.25m (depth), we can compute the AMBF based on the above prescribed setbacks as follows:

Allow. Max. Bldg. Width = Lot Frontage - Left Setback - Right Setback = 96m - 3m - 3m = 90m
Allow. Max. Bldg. Depth = Lot Depth - Front Setback - Rear Setback = 131.25m - 6m - 3m = 122.25m
AMBF (based on Setback Requirements) = 90m x 122.25m = 11,002.50sqm

Lastly, we can also check the AMBF based on Lot Types as seen in Figures VIII.2 through VIII.8. As the property is an Inside Lot and the use/occupancy is Group E, we see that the required open space (TOSL) is 15% of the TLA. Therefore, the AMBF can be computed as,

AMBF (based on Lot Type) = TLA - 15% of TLA = 12,600sqm - 0.15 x 12,600sqm = 10,710.00sqm

Now, we have calculated three different values of the AMBF:

AMBF (based on Max. PSO) = 9,450.00 sqm
AMBF (based on Setback Requirements) = 11,002.50 sqm
AMBF (based on Lot Type) = 10,710.00 sqm

Since we are looking for the MAXIMUM, then, the LEAST value shall govern as it is the most stringent. Therefore, the AMBF is c. 9,450.00 sqm.

Q#2: Once the building is situated in the center of his property, what would be the actual total area of the front and rear yards?
a. 3,768.00 sqm
b. 3,960.00 sqm
c. 11,736.00 sqm
d. 3,712.50 sqm

Since the building is required to have all sides equal in dimension, then, we are looking at a square-shaped building plan. As the lot is rectangular in shape, where the width is smaller than the depth, then, the maximum allowable width of the building must govern as the measurement for all sides to obtain a square-shaped plan.

Based on Table VIII.3 (Setback Requirements), the allowable maximum width of the building is up to 90m (as there should be setbacks of 3m on both sides). This means that the square-shaped building is 90m x 90m in maximum dimensions. So, once the building is positioned at the center of the lot, the remaining space for the front and rear yards can be computed as,

Front & Rear Yard Total Depth = Lot Depth - Max. Bldg. Depth = 131.25m - 90m = 41.25m
Front & Rear Yard Total Areas = Front & Rear Yard Total Depth x Lot Frontage = 41.25m x 96m = 3,960sqm

The actual area for each of the front and rear yards is equal as the building is positioned in the center (1,980 sqm each yard) or 3,960 sqm total for both. Therefore, the answer is b. 3,960.00 sqm.

Q#3: This project would fall under which use/character of occupancy?
a. Division C-1
b. Division C-2
c. Division E-2
d. Division E-1

Use = Retail Establishments = Group E (Business and Mercantile), Division 2 (Retail Stores) per Sec. 701 and Table VII.1.
Zoning Classification = Commercial C-2 per Table VII.1

Therefore, answer is c. Division E-2 (or Zone C-2).

Q#4: What is the elevation from the lowest point to the highest point of the natural grade line of the property?
a. 4,500.00 mm
b. 6,562.50 mm
c. 1,920.00 mm
d. 4,800.00 mm

Since the entire lot is sloped from east downwards west (along the axis of the 96-m lot width parallel to the road) at 5%, then, the elevation can be computed as,

Elevation = Slope x Lot Width = 0.05 x 96m = 4.8m = 4800mm

Therefore, the elevation from the lowest to the highest point of the property is 4.8m or d. 4,800.00 mm.

Q#5: What would be the actual Total Gross Floor Area (TGFA) of the building?
a. 24,300.00 sqm
b. 25,392.00 sqm
c. 32,400.00 sqm
d. 33,856.00 sqm

Recall that in Rule VII (Guidelines on Building Bulk and Development Controls), the Total Gross Floor Area (TGFA) is defined as,

"The total floor space within the main and auxiliary buildings primarily consisting of the GFA and all other enclosed areas together with all other usable horizontal areas/surfaces above and below establish grade level that are all physically attached to the building/s which SHALL CONSISTS of the following:

1. Covered areas used for parking and driveways, services and UTILITIES. The TGFA specifically excludes provisions for courts above grade level;
2. Vertical penetrations in parking floors where no residential or office units are present;
3. UNCOVERED AREAS for helipads, AIR-CONDITIONING COOLING TOWERS or ACCU BALCONIES, OVERHEAD WATER TANKS, ROOF DECKS, laundry areas and cages...xxx..."

Since TGFA is the total floor area INCLUDING ROOF DECKS and OTHER services, it basically means it is the ENTIRE CONSTRUCTION FLOOR AREA (CFA). Note that the TGFA does NOT include uncovered parking areas.

As our actual building footprint is 90m x 90m or 8,100sqm (measured at ground level), with the building having 3 storeys and 1 roof deck, and there are no other building projections or sub-grade floors mentioned, the TGFA can easily be computed as,

Actual Building Footprint x Number of Storeys (including Roof Deck) = 8,100sqm x 4 = 32,400sqm

Therefore, the actual TGFA is c. 32,400.00 sqm.

Q#6: Based on the preferred average size of leasable units, how many actual shops/stores can the building have?
a. About 90 units
b. About 189 units
c. About 355 units
d. About 142 units

Given average size of each leasable unit = 68.50 sqm (no greater than 70.00 sqm)
Given leasable areas per storey = 40%
Calculated actual floor area per storey = 90m x 90m = 8,100 sqm
# of storeys with leasable units = 3

Based on the given parameters and calculated floor areas, we can compute the actual quantity of leasable units as,

Leasable Areas per storey = 40% x Actual Floor Area = 0.40 x 8,100sqm = 3,240 sqm
Total leasable areas inside building = 3,240sqm x 3 storeys = 9,720 sqm
# of Leasable Units = Total Leasable Area in Building / Avg. Area of Leasable Unit = 141.9 or ~142 Units

Therefore, the actual number of shops/stores the building can have is d. About 142 units.

Q#7: Using the minimum prescribed parking space for cars in perpendicular parking layout, how much total area, at the minimum, will be needed for the actual on-site car parking?
a. 887.50 sqm of car parking area
b. 1,775.00 sqm of car parking area
c. 2,362.50 sqm of car parking area
d. 1,125.00 sqm of car parking area

The minimum dimensions for a parking space for cars is given in Sec. 707.4.b,

"The size of an average automobile (car) parking slot must be computed at 2.50 METERS BY 5.00 METERS for PERPENDICULAR or diagonal parking and at 2.15 meters by 6.00 meters for parallel parking...xxx..."

Since we will be using perpendicular parking layout, then, each car parking slot will have an area of,

Parking Area per slot = 2.5m x 5m = 12.5sqm (perpendicular car parking)

The minimum required number of parking slots based on building use/occupancy (Commercial Units) is given in Table VII.4, under 5.2 (Division E-2) "Units located in office, COMMERCIAL or mixed-use condominium buidings/structures regardless of number of storeys", where it reads,

"Units with a gross floor area of from 18.00 to 40.00 sq. meters - provide one (1) pooled parking slot for every two (2) units or for a fraction thereof;
Unit with a gross floor area of from 41.00 to 70.00 sq. meters - provide one (1) parking slot for each unit; and
Unit with a gross floor area of more than 70.00 sq. meters provide one (1) parking slot for every 70.00 sq. meters and for a fraction thereof."

Since the floor area of all our commercial/leasable retail units will never go past 70.00 sqm each (average provided is 68.5 sqm), then, the parking ratio of 1 : 1 shall be used. So,

# of Parking Slots (1:1 ratio) = # of Leasable Units = 142 slots
Total Parking Area = Parking Area per slot x # of Parking Slots = 12.5sqm x 142 = 1,775sqm

Therefore, the actual total area for parking (on a perpendicular layout) on-site is b. 1,775.00 sqm of car parking area.

Q#8: Based on the design criteria of your client, what would be the actual Gross Floor Area (GFA) of the building?
a. 20,665.00 sqm
b. 24,300.00 sqm
c. 18,225.00 sqm
d. 9,720.00 sqm

Recall that in Rule VII (Guidelines on Building Bulk and Development Controls), the Gross Floor Area (GFA) is defined as,

"The total floor space within the perimeter of the permanent external building walls (inclusive of main and auxiliary buildings) such as office areas, residential areas, corridors, lobbies and mezzanine level/s. The GFA shall also include building projections which may serve as floors or platforms that are directly connected to/integrated with areas within the building/structure, e.g. balconies and the GFA EXCLUDES the following:

1. Covered areas used for parking and driveways, services and UTILITIES;
2. Vertical penetrations in parking floors where no residential or office units are present;
3. UNCOVERED AREAS for helipads, AIR-CONDITIONING COOLING TOWERS or ACCU BALCONIES, OVERHEAD WATER TANKS, ROOF DECKS, laundry areas and cages...xxx..."

In short, the above listed (a) to (c) in the code is EXCLUDED in the GFA, while it is INCLUDED in the TGFA.

The design criteria during your consultation with the client specifically states that in EACH STOREY, the alloted spaces shall be,

40% = leasable areas (i.e., retail units)
45% = non-leasable areas (i.e., circulation, common areas, all open for public use, such as toilets, elevators, stairs, if any)
15% = utility and service areas (restricted access)

So, in each storey, if the TGFA includes all (the 100%) of the spaces as enumerated above, the GFA must EXCLUDE the areas for UTILITY AND SERVICE. This means the GFA only consists of the 40% leasable area + the 45% non-leasable areas open to public use = 85% of the floor area per storey.

On the other hand, the entire roof deck (100% of the roof deck floor area) which is included in the TGFA, is now excluded entirely in the GFA based on the code provision. Meaning, the entire roof deck floor area will NOT be counted in any GFA computations.

This means that the GFA of the entire project would be,

85% x Floor Area per Storey x # of Storeys = 0.85 x 8,100sqm x 3 = 20,655sqm

Therefore, based on the design criteria, the actual GFA of the building is a. 20,655.00 sqm.

Q#9: Based on the type of use or occupancy of the project, what is the Building Height Limit (BHL)?
a. 15.00 meters
b. 18.00 meters
c. 10.00 meters
d. 21.00 meters

As per Table VII.2, the BHL for Commercial 2 (C-2 Zone) is "18.00 meters above highest grade". As there are no specific prescriptions for any other development controls related to angular views for C-2 structures, or any mention of approaching/departing planes for areas near an airport zone, or any mention of stricter local ordinances in the design problem, then, the table shall be deemed as the most restrictive.

Therefore, the Building Height Limit (BHL) is b. 18.00 meters (measured from the topmost grade level of the property).

Q#10: What is the actual building height of the structure based on established grade and the design criteria of your client?
a. 17.30 meters
b. 14.60 meters
c. 12.20 meters
d. 14.90 meters

In the notes prescribed for establishing grade in Table VII.2.a, and Figure VII.3,

"In case of sloping grade where the edges of the building footprint (AMBF) running perpendicular to the RROW has a difference in elevation of less than 3.00 meters, the highest adjoining natural grade (ground surface) or finished grade (sidewalk surface) shall be considered the established grade elevation;

In case of sloping grade where the edge of the building footprint (AMBF) running perperndicular to the RROW has a difference in elevation of MORE THAN 3.00 METERS, the AVERAGE GRADE LEVEL of the building footprint (AMBF) shall be considered the ESTABLISHED GRADE ELEVATION;

The building/structure height shall be measured from the highest adjoining public sidewalk (finished grade) or ground surface (natural grade); PROVIDED, that the height measured from the LOWEST ADJOINING SURFACE shall NOT EXCEED such maximum height BY MORE THAN 3.00 METERS...xxx"

Since we have already computed that the difference in elevation between the highest and lowest grade lines is 4.8m, then, we must consider the above provisions in the code pertaining to the established grade elevation if the difference in elevation is more than 3m.

So, since the road and the lot has a consistent slope, the average grade level of the building footprint can be considered as half of the difference of elevation, or 4.8m / 2 = 2.4m. This means that from the midpoint of the slope, we still have to add the 2.4m elevation to the actual building height measured from the topmost grade line.

Based on the design parameters, the floor-to-floor heights have already been given as,

Highest NGL to G/F = 1m
G/F to 2/F = 4.15m
2/F to 3/F = 3.85m
3/F to Roof Deck = 3.2m

This means the total height from Highest NGL to Roof Deck = 1m + 4.15m + 3.85m + 3.2m = 12.2m.

But we still have to add the calculated average grade level/difference in elevation of sloped lot, which is 2.4m to the above height. So, 12.2m + 2.4m = 14.6m

Lastly, we also must consider the 2.70-m high parapet wall in the calculation of the building height. As Sec. 707.2.a states that only "signages, masts, antennae, telecom towers, beacons, and the like" are EXCLUDED in the height above the roof of the building. So, 14.6m + 2.7m parapet = 17.3m.

Therefore, the actual total building height based on established grade is a. 17.30 meters.

Q#11: What is the actual FLAR of the project?
a. FLAR = 0.771
b. FLAR = 1.446
c. FLAR = 1.640
d. FLAR = 1.928

Recall that FLAR (or Floor to Lot Area Ratio) is the "ratio between the Gross Floor Area (GFA) of a building/structure and the Total Lot Area (TLA) of the lot/property on which it stands. The FLAR is determined by dividing the GFA of a building/structure by the TLA. The GFA of any proposed or existing building/structure should not exceed the prescribed FLAR multiplied by the TLA."

Take note that only the Gross Floor Area (GFA) and NOT the Total Gross Floor Area (TGFA) is considered in computing the actual FLAR of a building. So, based on our calculated GFA above, our FLAR can be easily computed as,

Actual FLAR = Actual GFA / TLA = 20,655sqm / 12,600sqm = 1.6392857 or 1.64

We can check Table VII.G.1 (Reference Table of FLAR Designation/Rights) to see if we exceeded the limits. According to the table, C-2 buildings have FLAR rights of "3.60 up to 9.00". This means our actual FLAR of 1.64 conforms with the code and there are no mentions of any other more restrictive FLAR limits from any local ordinances mentioned in the design problem.

Therefore, the actual FLAR of the project is c. FLAR = 1.640.

Q#12: If based on historical data within the locality and based on your past projects, the land development (construction of pavements, gates, fences, grading, drainage, exterior improvements, etc.) costs approx. Php 1,400/sqm and the building construction (actual structure, including decks, and MEPF systems) costs Php 28,000/sqm, how much will be your total estimated / probable construction costs for the whole project?
a. Php 953,758,400.00
b. Php 924,840,000.00
c. Php 698,040,000.00
d. Php 913,500,000.00

Given that there are two separate costs per square meter mentioned in the question, we must categorize which areas of the project fall under land development and building construction.

For the building construction (actual building/s), we can easily compute it based on the design criteria and our previous calculations above as, 90m x 90m footprint x (3 storeys + 1 roof deck), which is actually our equation for the TGFA (or total construction floor area, CFA), then multiplying the costs per sqm. So,

Building Construction Cost = TGFA x Costs/sqm = 32,400 sqm x Php28,000/sqm = Php 907,200,000

For the land development (areas excluding the building), we can also easily compute it by just subtracting the building footprint from the total lot area, then multiplying the costs per sqm. So,

Land Dev't Cost = (TLA - Actual Bldg. Footprint) x Costs/sqm = (12,600sqm - 8,100sqm) x Php1,400/sqm = Php 6,300,000

The total estimated / probable construction costs would then be,

Total Estimated Costs = Php 907,200,000 (for Bldg.) + Php 6,300,000 (for Land Dev't) = Php 913,500,000

Therefore, the answer is d. Php 913,500,000.00.

Q#13: What would be the actual percentage of impervious surface area of the project if you allocated the minimum allowable true open space?
a. 8.9%
b. 14.1%
c. 27.8%
d. 30.7%

"True open space" is the Unpaved Surface Area (USA) as per Sec. 803.3.b.ii, it reads,

"Unpaved areas within the lot that are with exposed soil and planted (softscaped), i.e., the Unpaved Surface Areas (USA); this sub-classification is the TRUE OPEN SPACE."

In Table VIII.1, we can see that the minimum USA for C-2 zoned commercial buildings without firewalls is prescribed as 5% of the TLA. So,

Minimum USA = 5% x TLA = 0.05 x 12,600sqm = 630sqm

Since in our previous computation, we know that our actual Building Footprint or site occupancy is 8,100sqm (i.e., 90m x 90m bldg.), our actual Total Open Space within Lot (TOSL) can easily be calculated as,

Actual TOSL = TLA - Actual Building Footprint = 12,600sqm - 8,100sqm = 4,500sqm

Since TOSL = ISA + USA as per Table VIII.1, then, computing the Actual Impervious Surface Area (ISA), given the minimum USA will be,

Actual ISA = Actual TOSL - Minimum USA = 4,500sqm - 630sqm = 3,870sqm

Therefore, the actual percentage of ISA of the project is 3,870sqm / 12,600sqm = 0.3071428 or d. 30.7%.

Q#14: What adjustments do you need to do for the actual USA to conform with the minimum prescribed in the code?
a. We need to increase the USA to 20%.
b. We need to increase the USA by about 1,350sqm.
c. We need to increase the USA by exactly 3x the minimum allotted area.
d. No adjustments needed as the maximum ISA and minimum USA requirements are both met.

However, since in Table VIII.1, we can also see that the maximum ISA (paved open space) can only be at 20% of the TLA (i.e., 0.20 x 12,600sqm = 2,520sqm), then, our calculated actual ISA of 3,870sqm will NOT conform with the code. We must decrease the actual ISA and increase the minimum USA by 3,870sqm - 2,520sqm = 1,350sqm. So,

Conforming USA = Minimum USA + 1,350sqm = 630sqm + 1,350sqm = 1,980sqm or 15.7% of the TLA
Conforming ISA = Actual ISA - 1,350sqm = 3,870sqm - 1,350sqm = 2,520sqm or 20% of the TLA

The actual percentage of ISA of the project will now be 2,520sqm / 12,600sqm = 20%; while the actual percentage of USA of the project will now be 1,980sqm / 12,600sqm = 15.7%

Therefore, the adjustments we need to do is b. We need to increase the USA by about 1,350sqm (hence, reducing the ISA by the same amount).