Replacing part of door frame

[wijcc]

Hi..
I need to replace one side of a external door frame. The problem is between the wooden frame and concrete breeze blocks there was either concrete or mortar.. which had crumbled from about mid height approx to the bottom of the door frame, it was a 1 to 2 cm thick. I need to replace this, but unsure whether I need to use a concrete mix and how long I need to leave it to dry before I can attached the new door frame. Can you anyone offer me any advice?
Thank you in advance guys

 

[foxhole]

Easier to replace entire frame than mess around patching half of it.

 

[wijcc]

I will still have to put /apply the concrete mix between the door frame, so any ideas how long i would need to let it dry before i can fit the new door frame please?

 

[lostinthelight]

I will still have to put /apply the concrete mix between the door frame, so any ideas how long i would need to let it dry before i can fit the new door frame please?

Pack the frame, fix it and then foam it?