How to organize a project by floors and zones (the LBS)

What an LBS is, and what it is not

A Location Breakdown Structure (LBS) splits the project by where: site, building, floor, zone. It is a tree, and every branch is a physical place a person can walk to with a tape measure and a set of drawings.

It is often confused with the Work Breakdown Structure (WBS) or the cost breakdown, which split the project by what: concrete, masonry, drywall, electrical; or, in a cost code system, by division and section. Both are needed, and they are not rivals. They are the two axes of the same grid.

A line item of the estimate is the crossing of the two: gypsum board (what) on Level 5, Zone A (where).

A quantity without an address

Take a small change: 130 SF of drywall to close up walls after a plumbing reroute. As a number it is correct, and almost useless. The estimator can price it. Nobody else can do anything with it.

Now say 130 SF, 57 of them on Level 3 and 73 on Level 7. The superintendent knows that Level 3 is already taped and painted, so those 57 SF are rework in a finished area, and they will need protection and a painter coming back. Level 7 is still open, so those 73 SF ride along with the hanging crew at no extra mobilization. The scheduler knows which activity to touch. The project manager knows the change order is two conversations, not one.

The quantity did not change. What changed is everything anyone can decide with it. That is the whole argument for an LBS: a number with an address can be scheduled, checked, billed and fixed. A number without one can only be added up.

The levels: from the project down to the unit

Most building projects need the same five levels. Not all of them every time: a single building does not need a building level, and a warehouse may not need units. But this is the order, and levels are not skipped or swapped.

Where to stop

The most common way to ruin an LBS is to keep going. After the unit come the rooms: kitchen, bath, bedroom, closet. It feels thorough. It is not. The smallest location is the unit, the suite or the shop, never the rooms inside it.

The reason is practical. A location earns its place when someone schedules, tracks, inspects or bills against it. Nobody schedules the drywall of a closet. Nobody bills the second bedroom separately. Nobody sends a crew to one bathroom and another crew to the kitchen next to it. A level that nobody uses is only a level where quantities get lost, because every item now has to be assigned to a room, and half of them (the wall between the kitchen and the living room) belong to two.

Below the unit, count, don't organize. Three bathrooms per unit, twelve doors, one kitchen: those are attributes of the unit, or quantities in the takeoff, not branches of the tree. When a punch item needs more precision than «Unit 503», the description gives it: «Unit 503, primary bath, vanity mirror».

On non-residential work the unit level may disappear. An office floor leased whole has no units; zones are enough. A hospital wing may use departments instead. The rule does not change: stop at the smallest space that is built, inspected or handed over as a whole.

Naming floors and zones so the names survive

An LBS is used by a dozen people across two or three years, printed on daily reports, typed into RFIs and read out loud over a radio. The names have to survive all of that. A few rules do most of the work.

• Use the architect's level names wherever possible. The drawings already say «Level 3» on every plan and section; an LBS that says «3rd Floor» forces a translation every time someone cross-checks.
• Give every name a short code and a readable label: L03 · Level 3. The code sorts and fits in a column; the label is what people say.
• Pad the numbers. L01 … L10, not L1 … L10. Otherwise a sorted list puts Level 10 right after Level 1, and every report comes out in the wrong order.
• Say which one is the ground floor. In the US, Level 1 or the 1st floor is at grade. In the UK, Spain and parts of Latin America the ground floor has its own name and the «first floor» is one up. On an international team, write it down once.
• Name zones by position, not by trade or by company. Zone A / Zone B, or North / South, or Grid 1–6 / Grid 6–12. «Drywall area» or «Smith Electric side» stops making sense the day the next trade walks in.
• Number units the way the owner will. Apartment 503 on Level 5 is a convention buyers, mail carriers and first responders already understand. Use it.
• Never encode something that will change. The tenant's name, the phase, the contractor, the unit type. «Retail 2» survives a new lease; «Coffee shop» does not.

Typical floors: copy, don't just multiply

Residential towers, hotels and dormitories repeat the same floor plan five, ten or thirty times. The temptation is obvious: measure the typical floor once and multiply by the number of floors. For a schematic estimate that is exactly right. It is fast, and at that stage the difference between floors is smaller than the uncertainty of the number.

The trouble comes later. A multiplied floor has no address. «Typical floor × 8» cannot be scheduled floor by floor, cannot show that Level 6 is done and Level 7 is not, cannot bill Level 4 this month and Level 5 next month, and cannot absorb the change that only affects Level 10. The day any of those happens, somebody has to explode the multiplier into eight rows, by hand, usually under pressure.

The method that holds up is to measure once and copy: take off the typical floor carefully, then create each floor as its own location carrying its own copy of those quantities. The work is the same; the result is eight floors that can each be edited, tracked and billed. Keep a note on each one saying which floor it was copied from, so an error in the original can be traced to the copies.

Typical is a claim, not a fact

Before copying, check what is actually typical. The usual exceptions:

• The first residential floor sits on the podium or the transfer slab, often with terraces, amenity rooms or a different structure.
• The top floor has the roof above it: different ceiling heights, penthouse units, roof drains running through it, mechanical shafts ending.
• Setbacks change the footprint partway up.
• Unit mix changes: two units combined into one, a different corner unit type.

Copy the typical, then edit the exceptions on their own floors. That is exactly what a multiplier cannot do.

Zones sized for the work

Floors are given by the building. Zones are a decision, and the best rule for making it is this: a zone should be one crew's work package for one period, the piece of the floor a trade can start, finish and hand to the next trade in a predictable amount of time.

This is the idea behind location-based scheduling and its best-known chart, the line of balance. Instead of a list of bars, each activity is drawn as a line climbing through the locations over time: framing moves from Level 3 to Level 4 to Level 5, and drywall follows behind it. The slope of each line is the crew's production rate. When two lines converge, two trades are about to land in the same zone at the same time; when they drift apart, space is sitting idle. Takt planning pushes the same idea further: pick a rhythm (one zone per week, say) and size the zones so every trade can keep it. Location-based management has an established literature of its own, and the chart itself began in industrial production planning before construction adopted it for repetitive work.

None of that works if the zones are arbitrary. In practice:

• Zones of similar work content. If Zone A has twice the partitions of Zone B, the crew finishes one in two weeks and the other in one, and the rhythm breaks.
• Boundaries at physical breaks: the core, a corridor, a fire wall, an expansion joint, a pour break. A zone boundary through the middle of a unit invites arguments about who finished what.
• The same zones for every trade, whenever possible. If the concrete sub wants half-floor pours, place the pour break on the zone boundary rather than inventing a second set of zones.
• Few zones per floor. Two or three on a typical residential floor is common. Ten zones per floor turns the schedule into noise.
• The core as its own zone. Stairs, elevators, shafts and corridors follow a different sequence from the units, and often a different crew.

Worked example: a 10-story building with a podium

The numbers that follow are illustrative. They are chosen to show how the structure works, not as benchmarks for real partition quantities.

The tree

Note what is not there: no bedrooms, no bathrooms, no «typical floor × 8». The units appear as a list inside each zone, because turnover and punch need them, but the zone is where the crews and the schedule work.

How one quantity rolls up

Take interior gypsum board partitions, measured in square feet of wall. Every row below is a location the takeoff assigned the quantity to; the totals are just sums.

The same quantity, read across the tower by zone instead of by floor:

Now compare it with the shortcut. Typical floor × 8 = 11,800 × 8 = 94,400 SF. The real tower is 94,800. Four hundred square feet will not sink anybody's estimate. What matters is that with the multiplier nobody knows those 400 SF exist, or that they are on Level 10, and the drywall foreman plans Level 10 Zone B like every other zone and finishes a day late without anyone knowing why.

Each person reads the same table differently. The estimator prices 99,800 SF. The scheduler sees that each residential zone carries a similar load, so one zone per crew per period is a reasonable rhythm, with L10 Zone B a little heavier. The superintendent sees that the podium is a different job altogether, with little drywall and a lot of parking. And the project manager can bill L05 Zone A as complete the month it is complete.

One LBS, six uses

The payoff of doing this carefully is that the same tree is used everywhere, and every document on the project speaks the same geography.

The condition is that it really is the same tree. If the estimator uses «Floors 3–10», the scheduler uses «Tower» and the superintendent uses «North» and «South», there are three LBSs, and every report between them needs a translation that someone will get wrong. Agree on the tree before the takeoff starts, and change it in one place when it has to change.

Several buildings on one project

Multi-building jobs (two towers on a shared podium, a campus, a row of warehouses) add a level and bring a problem: name collisions. Every building has a Level 1. Each one may have a Unit 101. A punch item that says «Unit 101» on a three-building job is a coin toss.

• Put the building in every code. T1-L05-A, not L05-A. The prefix feels redundant on the day you create it and saves you on the day two reports are merged.
• Keep building codes away from floor codes. If the basement is «B1», the building cannot be «B1». Use T1/T2 for towers, P1/P2 for parking levels, or letters for buildings and numbers for floors, and write the convention down.
• Treat a shared podium as its own building. Its floors do not belong to either tower, and its schedule usually precedes both. The towers start at the first floor above it.
• Give sitework its own branch at the building level. Paving, utilities and landscaping are real locations with their own crews; lumping them into «Building 1» hides them.
• Follow the owner's unit numbering if they already have one. If Tower 2 units are numbered 2501, 2502…, adopt it rather than inventing yours.

The most common mistakes

• Going down to rooms. Hundreds of locations nobody schedules, and quantities split arbitrarily between them.
• Multiplying typical floors until the end, then discovering at the first pay application that there is no way to bill Level 4 alone.
• Mixing «what» into «where»: zones called «Drywall area» or «Electrical phase 2». Trades and phases belong to the WBS and the schedule, not the location tree.
• One LBS per department. Estimating by floor, scheduling by wing, field by grid line. Every hand-off between them is a translation.
• Zones of wildly different size, so no crew can hold a rhythm across them.
• Forgetting the places that are not floors: roof, site, façade, shafts, the parking ramp. Quantities with nowhere to go end up in «General» and stop being checkable.
• Renaming halfway through the job. Every RFI, photo and daily report written under the old names becomes harder to find.

Frequently asked questions