I am going to be installing a 72" w x 80" H sliding glass door into one of the exterior walls on my 8" concrete block house. There is currently a 30" w x 48" h window where the door opening will be. If I remove enough block to fit the door, there will still be at least one row of blocks that will be left above the door. How do I remove these blocks and then keep these blocks in place across the 72" door opening? I have standard 8' ceilings in this house.

 

I hate to even reply, but I think you have probably not considered what will happen when you remove cement blocks from your load bearing wall and make the opening wider than it currently is. The cement blocks that are left above your opening will have ZERO load bearing ability. You might as well remove them all the way up to the sill plate. You will then need to put in a header over the entire opening to support the weight of everything in your house including the roof, that is above that opening. this is what engineers are for- to calculate loads, and specify the sizing of beams. It is not for me to say or you to guess what size beam is needed. Before you do any of this, you'd want to build a temporary wall inside to support the floor joists and load above this new opening and build it as close as possible, and parallel to the cement block wall.

If I did have to guess, I'd error on the side of caution and just put in a 8" tall iron i-beam above the opening, which would sit in a pocket that is at least 8" wider than the rough opening for the door.

I'd suggest that you call a structural engineer and/or get an estimate from a masonry contractor to make your rough opening for you.

 

I always like to read posts by xsleeper. Always detailed, even when a difficult question is posed.

I hope you'll take his advice ourjem. You need an engineer to advise you.

 

I have done this, more than once, and I will tell you straight out it is NOT your average DIY project. The fist time was in a basement with a block foundation. My general contractor decided he wanted to create a walk out basement in his house. We created a temporary wall and covered it with plastic to control mess. Then we marked out our hole 3 inches wider for a buck frame of 2 x 8 pressure treated to cover the block foundation. We cut the hole with a concrete saw and took out all the block up to the rim joist. Put the 2X 8 buck frame to cover the block and screwed the doof in place. We just doubled up the rim joist, because the floor joist ran parallel to the wall we were working on. Extension jambs, casings and an aluminum covered exterior finished the job, yes I know you are not supposed to put aluminum over treated lumber, but we did it anyway, SHHHH. We actually put a 6' patio door and a 3'X 5' egress style double hung in the same wall. It sounded crazy to me at the time, but when the boss says do it and it was his house, so...... we did it.

Now if you have block walls going up much higher that it would be feasible to remove, you would probably need to grind out all the mortar between the course of blocks where the top of your door would be and put in some kind of steel lineal, and that would be out of my scope to help you, perhaps a block layer could assist in that part.

By all means this is not to be taken as any a recommendation to do this type of home improvement. It is potentially very dangerous, and like XSleeper says it would be best to acquire the services of an engineer.

Whatever you do, GOOD LUCK!

 

Bumping an old thread;

I have a 72" wide window in an concrete block wall and I'd like replace it with a 72" sliding glass door.

I'm guessing this should be a lot less involved than what is described above because the 72" window should have a lintel that would already be adequate for the door?

Same opening, same load, correct?

TIA.

Tipsy

 

Tipsy, in theory, yes. In practicality, make sure the lintel is there before you remove the window. Like Brant said in his original post, if there isn't a lintel, all those block will have nothing to hold them, and they will crash down, leaving nothing to support your top plate and the weight on it.
Now, you have to consider the rough opening. What is the RO of the existing window? You may have to pull a piece of trim off to see. What is the RO of the proposed door? If it will fit, you're on second base.

 

Thanks for the reply. I'm not certain of the RO for the proposed door...I'm still shopping different brands. But plan to buy a standard 6' slider...most likely made by PGT.

Is it possible there is no lentil above the existing window? What else could be supporting the structure?

Tipsy

 

I would say with certainty there is a lintel. But, I can't see it, so I can't give you a green light. Exploratory surgery is in the offing I'd say. You may have a solid "false" concrete block lintel, which looks like concrete block, but is a solid 7 or8' off solid concrete filled with rebar that acts as a great lintel. Even the joint lines are molded to look real.

 

I see. I have little experience working with concrete block so I wasn't aware that this was a possibility.

Even, so...if the house were constructed with the "false" concrete block lintel...would this not be adequate structure for what I'd like to do?

Tipsy

 

Oh, absolutely. It has been holding your house off the window all these years. Our caution is built in. We want to make sure you do a safe job. If you want, you can post pictures of the existing block over the window. It may help us help decide if it is continuous lintel or not. You can post pix by http://forum.doityourself.com/electr...your-post.html

 

Thanks. I spoke with a structural engineer today who is familiar with the construction of these homes. He told me there is, in fact, a concrete lintel and that it would be more than adequate to support the load (which is effectively, unchanged). He's worked in the neighborhood for years and said what I'm proposing to do is a common retrofit.

I can't post any useful photos at the moment. The exterior is stucco'd and the interior is still dry-walled. I'm not going to tear anything apart until I source a door.

Thanks again.

Tipsy