Should Terran build bunkers after the wall during 2v2?

Question

Let's consider a match of 2v2 where:

1. Terran is in team with either Zerg or Protoss;
2. Terran can't wall-in for both bases together (their bases are too far away from each other).

From one perspective Terran should close the entrance to their own base with barracks/supply AND bunker. In this case, their 4 marines get 400 more hit-points.

From another perspective, very rarely will opponents attack a walled Terran. Instead they will go to the unwalled Zerg/Protoss. In this case, Terran will spend 100 minerals per each bunker build without real value: instead of taking 2 additional marines per bunker to help their teammate, they will keep concrete on the trash at their own base.

What do you think of that: should the Terran build bunkers on their own choke behind the wall?

Thanks.

Answer 1

Your question seems to be Should the Terran build bunkers as part of their initial wall-in?

If that's your question, I would advise not building bunkers as part of the wall. The cost of building a very early bunker just in case an opponent is rushing is not worth it. Yes, you can salvage the cost back later, but spending 100 minerals on a bunker instead of a depot or 2 SCV's early on will slow down your economy and production.

If you are building a bunker to counter a specific threat, that's one thing. But building one just on the off chance you're rushed is over-committing in my opinion. The rush may be in the form of zerglings or zealots, in which case your bunker doesn't help at all (since you are already hiding behind a supply depot wall). And as you said, some people will see your wall and just head for your teammate, also wasting the bunker.

Answer 2

Should I wall my teammates?

In case it's Terran or Protoss, they can wall themselves.

In case it's Zerg, maybe, you can plan out an abusive strategy if you do so.
Please note that Zerg has an early queen and can produce units quickly so he has defense...

You should focus more on getting map vision so you can see them incoming and gather your armies than on building walls where they aren't necessary, you'll do more bad than good if your wall doesn't allow Banelings/Zealots to pass into those Marines an opponent has sent in...

Nor do you want the wall to be weak due to supply depots.

Should I place bunkers by my teammates?

Maybe, if they get continuous harassment just because the opponent has to push Zerg back it might be worth to place down bunkers at key positions. Bunkers can be salvaged later so you get a full return of your resources, just note that you do miss some resources by sending the SCV there...

Answer 3

What is walling?

Walling refers to the use of buildings in order to make a choke more narrow (and thus easier to defend) or even completely blocked off in some situations. Applications are usually defensive, but they can also be used offensively to trap players in early on, or in any likely place of battle (usually late game) to give an advantage to your ranged units fight against melee (or lesser ranged) units.

— Liquipedia II - Walling - Introduction

How is it used in different competetive settings?

Protoss

For Protoss players walling is most common when playing against Zerg. A Protoss player will usually wall the entrance to his main, leaving a 1x1 gap between buildings so that all units can pass while it can be completely blocked with a Zealot on hold position thus preventing Zerglings from entering the base.

Terran

Terran players create walls much more frequently than other races do because of the versatility they have from the Supply Depot's ability to lower into the ground as well as the ability of most of their buildings to Lift Off. Most common Terran walls are composed of two Supply Depots and a Barracks or one Barracks, one Factory and one Add on.

Zerg

Zerg players rarely use buildings to wall off. When in need of a block, Zerg often use units like Queens or Roaches. It is fairly common however to use buildings at the natural expansion versus Terran to create a narrow choke that is easy to block against a Hellion run by.

— Liquipedia II - Walling - Competitve Use

What are the disadvantages of walling?

When an enemy army that has units of equal or greater range than units of your own, the wall prevents you from attacking back, while the enemy can safely to attack the wall. This is a reason why Protoss do not normally wall against Terran, who gets marines, a ranged unit starting from T1.

A wall composed of weaker structures such as supply depots or pylons early on can present a false sense of security, as Baneling Bust, a rush strategy commonly performed by Zerg players, can easily break down the wall, leaving you left with few units to defend against the flood of zerglings breaching your wall. For this reason, Terran players tend to use Rax and Fact for their wall as they are much harder to destroy, and can still provide the door function by lifting off. Protoss do not have this advantage and would have to destroy the buliding to provide access.

A wall breached of supply depots or pylons can leave you supply blocked, rendering you unable to reinforce or produce more units during the attack.

— Liquipedia II - Walling - Disadvantages

More information available at Liquipedia II - Walling.

Answer 4

Should I use bunkers as part of my initial wall-in?

No, this will cause you to spend 100 minerals into a Bunker instead of 100 minerals into the next logical step of your BO, you will miss a Supply Depot and get a Supply Block or you build the Refinery later so you will not have the Gas for a Factory/Addon/Upgrade when you need it.

What can I use bunkers for?

A bunker is a defensive building that has 400 life points, which is roughly equal to the life points of about 9 Marines, so killing a Bunker with 4 Marines actually requires the opponent to kill 13 Marines.

This delays the opponent and allows you to produce less units, gets even better if you repair them.
By creating less production buildings and producing less units you free up Minerals and Gas which can be used to throw down an expansion or research technology.

This can allow you to get Tanks to become more defensive or perhaps a quick Banshee Eco Harass while your bunker(s) hold off those 4 Stalkers (in a 4 Warpgate + Proxy Pylon setting) that planned to go up your ramp so they can warp in 4 Zealots. Too bad for him, you could've even scouted him not producing any units back home so you knew this was coming...

A bunker isn't there to counter a specific threat, it is there to defend your smaller amount of units untill you get your real counter out.

What if my bunker makes them run to my teammates?

And if they run to your teammate, they will either run into his army or a similar defense. You can group up some marines and hellions/tanks and run behind your enemy so he gets attacked from both sides while refilling bunkers, putting tanks in siege mode, expanding or preparing a M/M/Hellion drop.

As said in my other answer, if you also have map vision at this time you can freely do what you want.

Caution: This excludes cloaked units, so get detection at key positions. (minerals, ramp, side, ...)

Should the Terran build bunkers on their own choke behind the wall?

Depends... This allows your units to become more protected as you have a high ground advantage istead of at the bottom of the ramp and you are essentially forcing your opponent to get in a choke point on your ramp. But, if you are planning to expand to a natural that is outside the ramp then you might want to consider to put the bunkers on lower ground instead.

Answer 5

Yes. In 2v2, unless you are planning an early rush with your partner, or unless your scouting has proven that the opposing team will not early rush, you actually should build a bunker in tandem with your wall-in.

2v2 differs from 1v1 in a crucial way.- In a 1v1, if your build order is flawless, it is impossible for the opponent to overwhelm you early with a much greater number of troops. In 2v2, that is not the case. 2 early armies at your doorstep will overwhelm you.

That means that in 2v2, you need to take maximum advantage of buildings and units that give you the ability to handle armies of greater supply than yours. A bunker in front, with scvs repairing, can hold off far more opposition than 100 minerals should ever allow. The fact that you have 2 less marines or a slowed buildup is offset by the tactical advantage of controlling where the opposing army can attack.

When your team's bases are separate, it is easy for the opposing team to wedge themselves in-between, splitting your armies. The cost-effectiveness of a bunker is invaluable to offset this disadvantage. It also allows you to use the whole of your army to run to your ally's aid without worrying too much that the opponents will fork the next wave into your base.

A more difficult question is whether or not to put a defensive cannon as part of your 2v2 build order as protoss. So good, but so expensive!