I have a concrete garage with an opening measuring 99" wide by 85" high. There is 10" of concrete from the door opening to the left and right walls and about 1' above. All walls are 8" thick and there is nothing above the garage except a wooden flat roof.
I want to enlarge the door opening by shaving off 4" of concrete on each side which requires two 8" deep cuts that are 7' long.
Will it significantly affect the structural integrity of the garage? In other words is there a chance it will collapse and do I need additional reinforcement?
What is the effort and materials involved in it? Can I do it myself if I rent a 14"-16" concrete saw? I will need to cut from both sides as it will not be deep enough to cut 8".
Is there anything else I need to be aware of for this kind of project?
- Is it worth paying $800 to a contractor rather than doing it myself?
Here are some pictures to give an idea (click for full size):