Dota 2 has backdooring protection which makes it very hard to backdoor sometimes, unless you bring your whole team or best carries.
I did however see that some heroes can backdoor very easily, Meepo and Nature Prophet for example.
So the question is; which heroes in Dota 2 can solo backdoor fast and with ease?
Best Answer
First of all, see here what backdooring actually is.
Tier 2, 3 and 4 towers and barracks have backdoor protection, which causes them to regenerate 90 hp per second and take only 25% damage from illusions if they are attacked without enemy creeps nearby.
So in order to backdoor successfully, a building needs to be low enough to be destroyed in a single hit, or the hero needs to be able to make more than 90 damage per second which after added damage reduction(armor) from tower which is ~ 55%-65% depending on the tier...you would need around 240 DPS to make the minimum impact on the tower,and since enemy team will rush to stop you as soon as possible you will need a lot more damage.
This is generally very difficult for most heroes for most if not all of the game, with backdooring typically being a team effort,single-hit destruction or mostly beneficial ability or item on your hero.
Things to look for in a backdooring hero:
Popular item choices to help you with this are Desolator(damage+armor reduction) and Necronomicon (DPS+extra creeps).
Some examples: