The Demoman is similar to the soldier, in that he has a type of technique to gain extreme mobility and the upper edge against opponents. The Demoman can Detonate his stickies or grenades to create an area of effect (AOE) blast radius around it, in the classification as an Explosive. These explosives can be used to damage enemies and knock them around if you do it right, this is where the Blast jumping comes in.

As the Demoman, doing a "Sticky jump" usually by crouching and jumping over a sticky bomb while detonating it, will propel you significantly farther than the soldier, and takes a lot more, in some cases, more than half the demoman's total health.

Though the sticky bomb launcher is typically used for blast jumping, a much more safer way in some cases is to use the grenade launcher. With the fuse time for each grenade being approximately 3.3 seconds, it takes longer to do.

Now that you know the basics of the Demoman's blast capabilities, we can move forward.

Now lets start with the basics, The Sticky bomb launcher. The sticky bomb launcher consumes about 75-90 HP each time you jump with it, which makes it nearly impractical to get anywhere efficiently, if not for the fact that it propels you nearly 2x as much as the soldier's rocket can. This means that you can get the most value out of your jumps, to get to the front lines quicker.

All you have to do to Blast jump with it is simply detonate it while crouch jumping over it. You need to properly aim and time your sticky bomb if you want to make the most out of it though, as an improper sticky jump can send you to the skybox and below.

Though this isnt very common, Demomen can use the grenades from the Grenade launcher to blast jump a little less farther than a rocket for soldier in most cases, if you time it just right, you can go as far as a well placed rocket with almost half the health it takes from a sticky jump.

To do a grenade jump, just Crouch jump over the grenade near the time it will explode (Approximately 3.3s) It will be slightly harder because you cannot manually detonate them, but if yo get the timing right it is simple to do.

Stickybomb launcher: Wtih the Stickybomb launcher you can do a pogo in the air with your stickybombs. It's only practical to use 2 at once because you will mostly die if you try a third, (though you can do it as much as you want with the sticky jumper) With overheal or resistances it is possible to live through, this is the prefered method over the double sticky jump in areas with obstacles or corners (Like pl_Badwater) ; The Double sticky jump can be done like the normal, but with 2. It takes double the amount of health, about as much as the sticky-pogo, be careful with it. (This is usually the method of getting around in open areas, as it is faster and efficient in that category. Like the majority of pl_Upward)

Grenade Launcher: You can sync the grenade and stickies for a Delayed sync jump, in which you shoot a grenade mid-air, sticky jump into the air slightly over it, and it detonates when you are over it. This is much more difficult to achieve than the sticky-pogo, so its best left to not attempt this unless you are experienced with it, as it is impractical for both normal use when it is pulled off, as it is when it is failed.

In conclusion, th e Demoman's Arsenal is very usefull for both combat and mobility, as it provides a wide range of mobile options for the Demoman that can be used in different situations more efficiently when called upon, it may take time to learn some of these tactics but i wish you the best of luck with your Demoman blast jumping.



Sources of Information Include Wiki pages and some of my own testing.
Videos by nate Fox and Bananamatic.