Left 4 Dead Wiki
L4d da construction.jpg
Chapter 3
The Construction Site
Campaign Dead Air
Dead Air Chapter Chronology
Chapter 2
The Crane
Chapter 3
The Construction Site
Chapter 4
The Terminal
"It figures, the only thing in the damn city not on fire is the one thing we need to burn down!"
"Hope this isn't the plane we saw..."

The Construction Site is the third chapter of the fourth campaign, Dead Air.

In this chapter, the Survivors exit the safe room and walk down an alleyway to find themselves in an unfinished construction site. The way to the next alley blocked by a barricade which must be removed by destroying attached gas canisters. This sets off an explosion which brings in a horde that must be combated.

Leaving the alleys, the Survivors cross a street to the grounds of a power plant and finally enter the airport's precincts. Unfortunately, this facility has been comprehensively damaged and its forecourt area is littered with crashed aircraft components. The Survivors enter the airport terminal's safe room via the parking garage sky-bridge.


Also see: Tactics

All campaign walkthroughs are done on Normal difficulty in single player, and are meant to give tips on what to do and generally point out things that might otherwise be missed.

There are, of course, a few key things to always remember:

  • Stop, look, and listen.
    • Being observant might alert you to something nasty ahead of time, like a Witch, Special Infected or Tank, and allow you to prepare yourself.
  • Teamwork.
    • This cannot be stressed enough. Left 4 Dead is supposed to be a cooperative game. Communicate with your teammates, if you're playing with others, or if you're by yourself with the AI, point out things they might otherwise miss. In all cases, watch out for each other and take care of each other. You are not going to survive the zombie apocalypse by yourself.
  • Be ready for anything.
  • Don't panic.

The good news is, you're one step closer to the airport. The bad news is, you have to get through an abandoned construction site to get there. However, it's possible, especially if you've made it this far. Stay focused, and you won't have much of a problem.


When starting from this chapter, all Bot Survivors will grab the Pump Shotgun.

When the Tier 2 weapons are found:

Otherwise, they will keep the weapons they from the last chapter (See The Crane for a list of weapons they will grab there).

The construction site.

Players start off in the safe room with First aid kits and Tier 1 weapons. On leaving the safe room, it is possible either to turn left (the most obvious route) or take a detour to the right and go around the block of storage rooms. Apart from encountering a few stray infected, the only benefit of the latter route is the chance of finding a second pistol in the third corner.

Leaving the safe room area, players follow a right-angled alley to the construction site. On the way, weapons will be found on a walk-up ledge to the right.

The construction site is complex, multi-level map containing numerous passive infected, weapons and explosive supplies. For example, there is a Gas Can on the scaffolding immediately ahead and Molotovs, Pipe bombs and an extra Pistol on the floor above. To the right is a more complete cement structure with an upper floor accessible via a plank or ladder and cable reel. Up here is blanket-covered corpse and Tier 2 weapons, more gas cans and other offensive-defensive supplies: depending on what The Director decides to spawn.

Visible on the far right at ground level is a barricade with some self-evident gas cans. Shooting these cans will destroy the barricade but also attract a horde.

There are many ways of dealing with this challenge:

  1. Spread the gifted gas cans out strategically, wait up on the floor with the corpse with or without the Tier 2 weapons and fight the horde from there. Be careful because a Smoker always spawns in the area from which players arrived. He is very accurate and will drag a player off the building unless either gunned down first or a shooter is smart enough to wait for him, crouched and behind the cover of a cement pillar.
  2. Stand on the scaffolding nearest the barricade. As a result of a glitch, Infected will not be able to get close but will instead repetitively run towards the ladder from the second floor, drop down, run a few feet towards the scaffolding, climb back up the ladder, run away in the opposite direction, turn around in an endless cycle. Even Special Infected will have trouble attacking. Only the Smoker really poses a threat, as he can pull a player away from this special area.
  3. Stand right in front of the barricade, turn 180° and players will see a small staircase. Bring the entire team up these stairs and into the corner. This position deals with Smokers efficiently because Survivors will only get constricted against the railing which is right beside the group and they can easily be freed.
  4. On the ground floor of the concrete structure, there is a rescue closet in the far right. If one or two people head out and destroy the barricade, then immediately run back to regroup at the closet; the entire team can fight from the closet. This provides an excellent choke point for the horde.
  5. Find an easily defensible corner and wait out the attack there: the simple solution.
  6. Shoot the barricade from the second floor of the semi-constructed building and run back to the safe room.
  7. Blow the barricade, rush past it and camp out at the ammo pile down the alley.

The street.

Once the above phase is complete, players proceed through the removed barricade into a long right-angled alleyway. Doors on both sides open into rooms often containing Pills, Pipe bombs and Molotovs.

An ammo pile and sometimes a spare pistol will be found in the angle of the alley.

At the end of the alley is a wide street which is filled with loitering Common Inflected. From here onward players are entering a dangerous space on account of the extreme likelihood of encountering Special Infected up to, and including, a Tank.

On entering the street, look in the store front on the left as supplies sometimes can be found inside. Opposite is the power plant, again look for weaponry on the ground at the entrance and in the storage room (pills and grenades) on the immediate left behind the crashed truck.

The path to take to move on is to the right of this crashed truck. Players can elect either to stay in the open avenues between the banks of electrical transformers or they can take a more protected route through the transformer stations. The former is more open with longer sight lines, whilst the latter is tighter but with better choke points and Smoker tongue-blocking obstacles. Note that the Common Infected in this area are generally more alert and teams must expect at least one hurry-up horde to attack.

In the early part of the route, a large dark double-width opening is worth entering for extra supplies such as a Pistol, Pills and grenades. It is possible, but less likely, that Tier 2 weapons will be in here too.

Care is needed from here on since a Tank has an above average chance of spawning in the transformer park if he has not yet already done so.

At the end of the transformer park, the route takes teams towards two windows (one of which is burning) and a pattern of intensely bright 'come here' lighting which leads players into a large garage containing pressure vessels and a small side door to a control room.

The airport entrance.

This control room is the last real supply point before the safe room and it is highly advisable to stock on here on the resources available: weapons, grenades, first aid kits, pills and ammo.

Continuing onward through the building brings players to a room with a broken wall and a set of double doors which both open onto the airport forecourt. Before leaving, it is recommended that a quick search be made of the two bathroom stalls found at the rear of this room; a grenade or pills sometimes spawn in there. At this point too, expect a hurry-up horde to attack; especially from the rear.

Before quitting the building, teams can thin out the number of Common Infected outside by throwing a pipe bomb through the aperture in the broken wall.

"What idiot bombed the airport?" Who indeed, for Metro International has been substantially damaged by high explosives.

Once in the airport forecourt, players must scramble over rubble and smashed aircraft components to reach the airport's front doors. There are numerous relatively alert and aggressive Common Infected in the area. Worse, is the risk posed by Smokers who will lurk high up on the overhead roof beams and road flyovers. A Witch may be encountered as well as a Tank. Players must anticipate at least one horde attack; more if a stray round should strike the alarmed car near the entrance to the parking garage. There is no question about it: this area is one of the most dangerous in the campaign and oftentimes a team will enter the equally risky parking garage low on both health and ammunition.

The airport's garage.

The airport doors are barricaded and the only way inside is via the sky-bridge from the parking garage. Opposite the garage entrance next to a pile of suitcases will be found at least one grenade and some pills. One of the most important things to avoid at this stage is the aforementioned alarmed car and it will be a distinct relief to get past it and into the parking garage.

The parking garage environment is a mix of light and dark spaces occupied by a significant number of relatively passive Common Infected. Teams must go up the ramps to the third floor. A Witch, Boomer, Hunter, Smoker and, if The Director wills it, a Tank must be anticipated. A Tank spawn is especially dangerous since the spaces are confined, the team may be hurting for health and ammo and the Tank has ready access to cars to throw at his opponents. It is not unknown for an entire team to be taken out by him in this area: thus forcing players to start all over again from the last safe room.

Once clear of the garage, players climb a short flight of stairs to the sky-bridge and can sprint to the safe room on the airport side. From time to time however a Witch may spawn in the sky-bridge and, worst case, right outside the safe room door. More rarely, a Tank has been reported even to spawn in the safe room itself!

The point is thus clear; this is one of the longest and most tricky chapters in the game.

Left 4 Dead 2 Version[]

In response to player feedback, an update on September 9th, 2011, changed how the survivors approach the Crescendo Event in the construction site. Players were originally able to exploit the event by throwing a molotov or pipe bomb through one of the wall's "windows" to hit the gas cans on the other side to trigger the event from a distance and run back to the safe room for safety. The windows are now sealed up to prevent this. Fences were also added to create a point of no return; a fence was added in the alleyway to prevent survivors returning to the safe room and a fence was also added on the floor above the closet to block survivors from getting back to the safe room as well.

It's still possible to throw a molotov or pipe bomb through the opening on the floor above where the second fence was added. With precise aiming, it will hit the gas cans and will activate the crescendo event and you can return to safe room since you didn't go over the fence in the alleyway yet.


The Survivors[]

Now that humans are controlling the Special Infected, things can only get harder. However, they can't spawn until you leave the safe room. That doesn't mean that you should let them have a good chance to find just the right spot, though! Hurry up and get your supplies, and get running!

Exiting the safe room should be done as swiftly as possible especially on this level. Dawdling inside will give the Infected the opportunity to set up deadly ambushes. On this level, there are several potentially excellent ambush positions for the Infected. Head on out, and don't let them get an advantage!

The Crescendo Event at the barricade will be a problem for a badly coordinated team of Survivors. Find a closed off corner and bunker down for a fight. Remember that in Versus, closets and choke points are removed. Also, do not attempt to run back to the safe room for this. The door cannot re-close in Versus.

The Tank has some dangerous spawn points in this level, particularly in the car park where cars are abundant and everyone is already hurt. Watch out for the Tank. Also, to some degree, this applies to the Witch. She can spawn in tight corridors where you cannot get past her. Seeing as Versus is about cooperation and speed, you may be forced to attempt to "cr0wn" her.

The safe room, despite being called the "safe room," may not be so "safe." Infected like to hang out in there and wait for the arrival of Survivors, especially lone Survivors. Because of this, do not rush ahead of your teammates when you are close to the safe room. You could end up getting killed. Stick with your team, remain cautious and you should be fine.

The Infected[]

See also: The Boomer, The Hunter, The Smoker, The Tank

The Survivors have made it far, but just their luck, they tipped you off to their location with an unfortunately placed exploding generator. Make them wish they were bombed with the airport!

Overall Tips

  • Any survivors that choose to run ahead of or fall behind their teammates will be much easier to seriously damage and kill. The farther away they are from their teammates, the more likely they are to be incapacitated or die before their teammates can reach them.
  • The Survivors all have outlines around them, showing their status and location. Green means they're healthy. Yellow means they're hurt. Red means they're low on health. Purple means they've been covered in Boomer bile. You can probably discern which to seek out first if possible.
  • Think like a Survivor. When you play as one, when are the worst times that something could come at you? Exploit that knowledge.
  • Teamwork, as aforementioned. Has a Boomer gotten their bile all over the Survivors? Jump one of them or a clean one. They can't see their teammates' aura until they're clean...and by then, it might be too late.
  • As much as teamwork is a strength for you and your enemies, a lack of it will be their downfall. If you can focus all of your energy on killing one of the Survivors, the rest will be that much easier to take down. Not only will they have one less gun, but they will have three Survivors to your three incapacitating Infected.

Boomers: Fat and fragile, you're not ideal for this world. To thrive in this level, you need to keep some things in mind: scaffolding, ledges and high places. These are all key to your success. During the Crescendo Event, make the Survivors' lives miserable. Vomit on them excessively. If they decide to fight from a corner with an overlooking ledge, use that ledge to your advantage. From up there, rain down your thick vomit and watch your bile-followers ravage the Survivors. Work with the other Special Infected by vomiting on them to create a distraction so your fellow Infected can attack easily. Alternatively, when an Infected attacks and causes their own distraction, seize the opportunity and cover them in bile!

Hunters: You are the leader of the Infected waves. You strike with lethal force and rip apart anyone in your way. Fortunately, cities are where you're at your peak. Leap from incredible heights and crush the Survivors. When the Survivors are about to burn the barricade and they are foolish enough to send only one Survivor away from their defensive position to do it, pounce him! You'll be able to do decent damage before his friends can help him. Mainly, do not attack as soon as you spawn, attack at the opportune moment: when a Survivor is alone or a small distance away from the group.

Smokers: This is a fabulous area for you. Scaffolding, high ledges and rooftops. Tug them from far away and separate the group. When the Survivors reach the barricade, grab someone if they go to start it alone. If the Survivors create fire, punish them. Grab a Survivor and drag him through it, the fire will conceal your presence and hurt the Survivor. Keep in mind that your role is not to charge in, but to hang back undetected and snare a lonesome Survivor.

Tanks: Here, the Tank can be strong. His actions can define the outcome of a Versus game easily. However, you lack the rooftops of the previous levels. Don't let this stop you. Improvise! So you can't be rid of them by tossing them over an edge. Why not toss something at them instead? On impact with the Survivors, objects that you can smash in to them instantly incapacitate them. So find something to bash about and go for it! It is also important to remember that once you've incapacitated someone, do not continue to beat that person until they die. If you do, you'll likely be killed first. Your priority are the ones who can still run, can still stand, and can still use their main weapons.


See also: Survival Mode

As it turns out, the barricade is not flammable. The waves of Infected are relentless and the barricade blocks the Survivors' escape. How long can they hold out?

Overall Tips

  • Teamwork is essential to long-term survival.
  • In this mode, most of the popular choke points, closets and easily defensible corners are removed. Even if you find one that has not been removed, it is not recommended that you fight from there as The Tank will quickly defeat you when he arrives.
  • You have an infinite amount of time to prepare. Use this to your advantage. Take as much time as you can to set up gas cans, propane tanks, oxygen tanks and to find a good place to fight from.
  • When searching for a place to fight from, remember that you need a location that not only limits where the horde attacks from, but also gives you a fair chance against the Tank. You either need to be able to fall back and deal with the Tank easily, or have a good enough vantage point to kill him before he can get too close.
  • Ammunition is a problem. Unless you are being overrun with Infected or fighting a Tank, try to use your pistols as much as possible. Conserving ammunition should be a priority, as trying to get more during a horde attack can often be fatal. When you do head out for ammunition, remember to take at least one teammate with you.

Scaffolding Method

The survivors on the scaffolding

The first and often most effective method is to spread the gas cans out strategically, find a nice and safe vantage point on a scaffolding of your choice, and fight the horde from there. Remember that your scaffolding location needs to give you and your team a chance at besting the Tank. At the very least, you need an emergency escape route to avoid him.

Stairs Method

Standing right in front of the barricade, turn 180° and you should see a small staircase. Bring the entire team up these stairs and into the corner. You can blow the barricade from there. This tactic deals with Smokers efficiently because Survivors will only get constricted against the railing which is right beside the group; therefore, they can easily be freed. However, this tactic does not deal with Tanks. When a Tank shows up, it is recommended that the entire team moves together and fights it elsewhere.

Window Method

Another position for the crescendo event is at the end of the upper floor of the half-finished building, you'll reach a window that is reachable by jumping. It gives a nice vantage point, you can see both sides of the wall. You can also shoot the gas can to start the event. Common Infected cannot reach you in this spot, but getting pounced by a Hunter could be fatal if no one else can get there. Needless to say, Smokers can still get you, too. Another downside: the ledge is very small, so the jump has to be precise.
"Back Door" Method
If you go back to the other barricade that is near the safe room, there is a area called "the back door deck" area. You can move towards this area and stock explosives (gas cans, propane tanks etc.) behind the damaged car; it will be a safe place to store explosives. Only two narrow ways are infected able to come through, and they usually come through the alley. This does not apply for Tanks and Smokers, as they usually try to attack from the catwalk to your upper right. When Tanks come, go onto the deck to your right and fend him off there, as the Tank cannot throw the Dumpster at you from there. Facing the Tank on the ground can be fatal, as he can hurl the Dumpster and instantly incapacitate you.


  • It's worth noting that the Survivors can light the barricade on fire and run back to the safe room, from the second level of the construction site, to fight the horde in a cheap, easy way. Along with this strategy, it's possible to throw a Molotov from just outside the safe room, lighting the barricade, and not risking the horde from spawning near the safe room, making it harder to get back.
    • To make this method easier, take a Molotov and turn left around the corner. Face the first concrete hole opening, and put your cross-hair right below the top of the window, then throw the Molotov. It should travel through that window, the second window, and light the gas cans on fire. This can also be done with a pipe bomb. This allows for easy survival of the Crescendo Event.
    • Due to an update in Left 4 Dead 2, this method no longer works and survivors are forced to set of the crescendo event directly in the construction site. They are also unable to return to the safe room once they proceed to the site.
  • This is the only chapter in Left 4 Dead with a Crescendo Event a player or even a bot (on usual occasions) can set off accidentally without preparing for the horde.
  • Although the airport would indicate that it has been bombed, as would the graffiti and the comments of the Survivors, it is never actually confirmed. It is entirely possible that planes have simply crashed into it as much debris from a single plane can be found scattered around.
  • This is the only chapter so far that requires the Survivors to shoot something to start the Crescendo Event, instead of simply activating something.
  • Quite often, AI-controlled Survivors will attempt to destroy some connecting planks that are serving as a bridge across the two construction platforms, thus annoying some players. If this happens, it is possible to jump across instead of doing a circle; however, this is not recommended with health below 40%, as you most likely will not be able to jump far enough.
  • After leaving the safe room, if you look past the fence, you will see that there is no riot fence in the street, no red car (only a green one), and no trash in the street.
  • When you wait at the safe room in this level (the last one) and watch the "bridge" that is leading to the safe room, you can see the spawning of the Special Infected.
  • This is the longest chapter in terms of traveling.
  • Also in Left 4 Dead 2, the side room next to the ending safe room cannot be entered, an invisible wall blocking human player entry, despite the door being usable. Despite numerous updates to balance the map's difficulty, this issue has never been fixed. Since the room is simply a spawn point for common infected and contains no items, it does not significantly affect gameplay. This issue is not present in Left 4 Dead.
  • In very rare cases, it's possible for Director to spawn The Witch on the spot where the gas can has been set off once the fire is gone. Provided no one has visibility on the burning barricade.
Left 4 Dead Left 4 Dead 2
L4d no mercy.jpg
No Mercy
The Apartments / The Subway / The Sewer / The Hospital / Rooftop Finale Price chopper.jpg
Dead Center
The Hotel / The Streets / The Mall / The Atrium
L4d achievement survive garage.png
Crash Course
The Alleys / The Truck Depot Finale Torch-Bearer.gif
The Passing
The Riverbank / The Underground / The Port
L4d death toll.jpg
Death Toll
The Turnpike / The Drains / The Church / The Town / Boathouse Finale Midnight rider.jpg
Dark Carnival
The Highway / The Fairgrounds / The Coaster / The Barns / The Concert
L4d dead air.jpg
Dead Air
The Greenhouse / The Crane / The Construction Site / The Terminal / Runway Finale Ragin cajun.jpg
Swamp Fever
Plank Country / The Swamp / Shanty Town / The Plantation
L4d blood harvest.jpg
Blood Harvest
The Woods / The Tunnel / The Bridge / The Train Station / Farmhouse Finale Weatherman.jpg
Hard Rain
The Milltown / The Sugar Mill / Mill Escape / Return To Town / Town Escape
Supreme sacrifice.png
The Sacrifice
The Docks / The Barge / Port Finale Bridge burner.jpg
The Parish
The Waterfront / The Park / The Cemetery / The Quarter / The Bridge
L4D last stand.jpg
The Last Stand
The Lighthouse Streamcrosser.jpg
Cold Stream
Alpine Creek / South Pine Stream / Memorial Bridge / Cut-throat Creek
L4d outbreak.jpg
Dam It
Orchard / Campground / Dam Achievement Still Standing.png
The Last Stand
The Junkyard / Lighthouse Finale