The original question was asked about how to raise a section of the garage ceiling to gain more height to allow the use of a car lift that needs to exceed the 10' ceiling height.
Carl, thanks for getting back to me with the information I needed. Based on what you gave me and my perception of the project, I will give you details on how I would go about making the modification and include a few of drawings. All of the drawings can be enlarged by clicking on the text next to them.
To get started you will need to mark off the area where the ceiling joists are going to be cut out. To do this, locate the five joists you want to cut out. There are two ways you can go about doing this job. Either from below, inside the garage, or above, in the attic of the garage. I prefer to do a little of both, which is made possbile after the ceiling is opened up. Mark of the area on the ceiling coming in 3' from the front of the garage or garage door and 6' from the back of the garage.
Click Photo to Enlarge
After you measure in the 3' distance from the front of the garage or garage door and the 6' distance from the back wall of the garage, that you have determined is where you want the joists to be cut out between, you will want to shore up or build a temporary wall that will go from the garage floor to underneath the sections of the joists that are going to remain. Once you get these walls built, you can use shim shingles to shim the walls up tight to the joists. If there is drywall on the ceiling, then you will build these temporary support wall under the drywall. The walls will be wedged in place and you can spot a couple of nails or 3" drywall screws into the joists to hold the walls in place.
Click Photo to Enlarge
The material from these walls will be used later in the attic area to build the kneewalls and do some framing, so hang onto the wood. Since you are going to reuse this wood (2 x 4's), it is best to put the walls together with screws. The walls will need to be wide enough to go a few inches beyond the two side joists that are going to remain on eithe side of the new opening. You will keep these walls in place untill all the framing for the new opening is complete. After that you will take them down and take them apart to use for the kneewalls and additional framing.
Once you have shored up the temporary walls, if the ceiling is drywalled, cut out the drywall in the section you marked off. You can do this by using a reciprocating saw by cutting along the outside edge of the joists that you are going to remove, using them as a guide for your blade. To cut the drywall across the joists on the ends, hold the saw so that the blade enters into the drywall on an angle and cut on your line from one side to the other. Make sure you hold the saw very tight so that it does not jump on you. It will not hurt if you cut into the joists a little since you are going to cut them out next.
Click Photo to Enlarge
Next you will need to remove the sections of joist by cutting them out one at a time. Make sure to strike a line using a chalk box, on the bottom of the joists that is 2'-8" out from the front wall or garage door and 5'-8" from the back wall. The reason for cutting at these measurements is because after you frame in the 4" wide header, the opening will be 3' from the garage door or front wall and 6' from the back wall, as you have chosen.
Having done that, take a framing square and mark straight lines on each side of the joist even with the bottom line you just struck. Cut out joist along these lines one joist at a time. Have some one hold up the opposite end of the joist and you cut them out with a reciprocating saw. Take your time and follwing the line as closely as possible to keep the ends of the remaining sections of joist as even as possbile.
After you remove all the joists, it will them be time to install the double 2 x 10 header or microlam beam. In our example we will be using a double 2 x 10 header on each end. You can nail one of the 2 x 10's first into the ends of the short sections of joist that remain on each end making sure to keep them spaced 16" on center so the patter matches their original location. After you nail in the first 2 x 10, cut a piece of 1/2" plywood about the same size as the 2 x 10 and nail it against the 2 x 10. Nail the other 2 x 10 against the plywood using 16 penny spikes that will go through the plywood and into the the first 2 x 10.
Click Photo to Enlarge
Since you will have a large area opened up with access to the attic, you can do some of your nailing from above using a ladder. After you complete all the frame work, you will need to cut away the old drywall and leave room to install new drywall on the ceiling around the entire area.
Take a look again at the following drawing that shows the collar ties in the attic that are either already in place or ones that you will install, being nailed from one roof rafter to the other. You may have to relocate or replace these if they are not high enough in the new opening you just created. This is important because they will be necessary for the installation of the drywall in ceiling portion of the new opening. Note that the new drywall will be installed on the new kneewalls, up the inside of the existing roof rafters, across the collar ties and back down the other kneewall.
Click Photo to Enlarge
Also notice, that besides building kneewalls over top of the headers you installed to provide the end walls of the new opening, you will need to build kneewalls and or additional framing over the two remaining side joists on each side of the new opening up to the collar ties and or rafters to completely enclose the area so that it can be drywalled. Of course this is assuming that the interior of the garage is already drywalled which is usually the case with an attached garage.
Click Photo to Enlarge
Your finished opening will be framed in and very strong. You can also double up the two remaining side joist on the inside of the opneing to make it more solid and eaiser to nail the kneewalls and additional framing. This is not necessary but as I said, will make the job a little easier for you.
Click Photo to Enlarge
I know that this is quite a long set of instructions, but hopefully it will be the answer you were looking for. Please let me know if you need any further assistance.
I hope this helps. Rick
Rick Maselli is Founder and Editor of Showroom411.com and Ask Rick