Raising a cinder block garage door

[franklin2]

Ok, I started the "Garage design" thread and got a lot of good responses. Still looking for a home to buy, and the latest one we are looking at has two nice cinder block garages. One of them has two garage doors and a smaller one has a single door on the end. I think this smaller garage would be a candidate for my auto lift. I am sure I can get inside and tear the ceiling out and "sister" some larger lumber to the rafters and raise the ceiling up. Actually the ceiling looks to be close to 10ft, so I could use it like I do now, and not raise the lift up all the way. But here's a problem;

The door opening is not tall enough. I pull in some tall SUV's sometimes, and larger trucks, and the opening is not tall enough, and it's made of block with I assume a metal piece across the opening called a lintel? Could I take two 2x4's and use masonry nails or sta-cons and attach those to either side of the opening, and then sit a 2x8 on top of the 2x4's and attach it to the blocks across the top, and then take a hammer and knock the blocks out from underneath, take the lintel out, raise it up higher, and mortar the lintel and partial blocks back in place? Has anyone done this before? I probably should put the support wood pieces on the inside also?

 

[Mace Canute]

Is your door in a side wall or end wall? How are your rafters constructed? Seems like a lot of work just to preserve a row or two of blocks and without a picture or three it's pretty hard to make a specific suggestion. I think it might be a lot easier (and it might be a better solution in the long run) to forget about saving any of the blocks above the door and just go for raising the lintel up to as high as needed.

 

[Trials]

A lintel is a load bearing beam, but in a conventional gable end roof design, there is very little load bearing happening on the front and back ends of the building, your roof trusses place most of the roof load on the 2 side walls and the stringers keep the walls from being pushed outwards, as such:

Photos of what you have to work with might help.
Another way to make your garage taller inside is to lower the floor jus sayin.

 

[RickB]

Must take a pretty good opener to raise a garage door made of cinder blocks :stirthepot::drink:

 

[pmsmechanic]

I'm going to assume from your description that the walls are cinder brick. If the door is on an end wall then you don't need a lintel. If the door is on a side wall then I would think you should be able to raise the lintel but it's hard to say with out being there or seeing pictures.

Or if raising the lintel will let you get larger vehicles in the re-enforce the rafters above the lift and cut out the ceiling by cutting out the bottom of the rafters.

 

[chim]

What is above the door you want to raise? As mentioned, pictures would help. If you have a couple courses of block above the door and it's a gable end with wood framing above - that's one thing. If it's on the wall where the trusses are bearing - that's something different altogether.

 

[Trials]

"cutting out the bottom of the rafters" Is a scary concept! Using the terms labeled here on this simple W roof truss diagram below, the bottom chord is under tensile stress as a result of weight bearing down on the A shaped frame composed of the top chords. The web is designed to reduce sag in the roofline and bottom chord by creating a structure that is dependant upon triangulation. If you mess with any of these parts you have significantly altered the strength of the design and you will create side loads on the bearing walls. Your load bearing side walls will tip outwards at the top and the building will collapse if you mess with those bottom chords, guaranteed.

I majored in Architectural Drafting and Structural Engineering was my strongest subject in school you can truss me on this.

 

[franklin2]

What is above the door you want to raise? As mentioned, pictures would help. If you have a couple courses of block above the door and it's a gable end with wood framing above - that's one thing. If it's on the wall where the trusses are bearing - that's something different altogether.

It has is your first scenario; The gable end of the building with 3 or 4 courses of block above the opening. I see what you guys are saying, the lintel just supports the block courses above, not the weight of the roof. I see also the one suggestion, just knock all the blocks out above the door up to the wood in the gable. If I keep any blocks I will have to re-install the lintel.

 

[franklin2]

"cutting out the bottom of the rafters" Is a scary concept! Using the terms labeled here on this simple W roof truss diagram below, the bottom chord is under tensile stress as a result of weight bearing down on the A shaped frame composed of the top chords. The web is designed to reduce sag in the roofline and bottom chord by creating a structure that is dependant upon triangulation. If you mess with any of these parts you have significantly altered the strength of the design and you will create side loads on the bearing walls. Your load bearing side walls will tip outwards at the top and the building will collapse if you mess with those bottom chords, guaranteed.

I majored in Architectural Drafting and Structural Engineering was my strongest subject in school you can truss me on this.

I was going to do this same thing where I live now but never got around to it. What I thought I could do was cut a 2x6 or 2x8 at the correct angles to sit on the top of the wall and come together at the top, and nail both to the side of the truss. Then drop down a certain amount and cut another 2x6 or 2x8 to create a "cross tie" to make it look like a "A" from the side. Probably use some sort of plywood to attach the cross tie to the rafters. Once that was in, then cut out the bottom of the truss.

I know the truss is complex, it must be because it's only made out of 2x4's. But I was going to make my auxiliary structure simpler and with larger wood. That should work correct?

 

[Trials]

...
I know the truss is complex, it must be because it's only made out of 2x4's. But I was going to make my auxiliary structure simpler and with larger wood. That should work correct?

Actually the truss is complex because it needs to be, the triangulation designed into its shape is what enables it to be constructed of 2X4 lumber, that and because it is a garage and not designed to support a second floor with living space. As for using larger lumber and not retaining a shape that is acceptably structural, nope, sorry but it doesn't work that way.

I get the feeling this is what you are trying to achieve, but you will notice that this type of roof truss requires 2 additional load bearing walls inside the structure:
(indicated by the little rectangles with the X's through them)