Cracked outbuilding roof

[jamin]

My out building has a concrete roof with a large crack. It looks like its been that way for a while. The prevous owner has stuck some felt over the crack (only the crack) but its far from water tight. Im intending on re felting the entire roof but would like to know what i should fill the crack with? I thought to shutter off the crack from underneath so I can wet pour something but have no idea what or even if thats the right technique!

Adivce greatly received.

 

[jm2000]

Yes thats a good enough idea...you can by a concrete grout in bags, or mix your own, a slurry of cement and sand.

You can also buy a concrete mastic that can be pumped into it with a mastic gun. Because the concrete has cracked, which is more than likely movment, this will act as a movement joint.

 

[Chukka63]

what about hot tar???

 

[jamin]

Im open to any viable, preferably cheap, suggestions!

 

[jm2000]

what about hot tar???

If as i suspect there IS re-bar in the concrete i would go for the movement joint option....flexible mastic or silicone.

 

[Chukka63]

i mentioned hot tar as thought that would penetrate the crack deeper.