# How to make large doorway in load-bearing concrete block wall?



## cortell (Nov 27, 2010)

I don't know of a prescriptive guide for creating a concrete header/beam, and doing it on gut feel is obviously a bad idea. The only way to do this without having someone engineer it is to use a built-up wood beam, using span tables in, e.g., the IRC. Alternatively, you could us a steel beam or engineered wood beam and see if you can find a supplier that will include the engineering as part of the purchase. 

Hammer-&-chiseling the opening isn't practical. You'll make a mess of the opening. Also, note that you are close to the corner, and there might be vertical rebar in that area (which must not be removed), so that could throw a major wrench into your plans. Unfortunately, you'll only know this by breaking open some blocks. There might also be horizontal bond beams at the top and bottom that could equally unravel your plans.

Honestly, this is not something a DIYer (electrician, included) should tackle alone. As I often recommend--hire a pro/engineer to design the solution, then save money by implementing it. But a DIYer doing both the design and implementation on something like this is often a recipe for disaster.


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## Arkitexas (Mar 10, 2011)

Do not attempt modifying this wall without professional assistance. You need an engineer or architect to design the opening/support and an experienced contractor to perform the work. 

P.S. Supporting a concrete wall/floor assembly with wood structure is not generally a good idea.


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## stuart45 (Jun 20, 2009)

To support the ceiling I would use these. However I would agree with the previous posters about getting the advice from an SE first about the beam.


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## md2lgyk (Jan 6, 2009)

Your method for making the header would never work. Most I've seen consisted of a piece of steel plate (1/4" thick or so) across the span, with blocks on top of it to fill in. Simple and quick. Your problem will be how to support everything while you build it. For sure, consult a structural engineer before doing anything. I built one such header the way I describe, but it wasn't nearly as wide as what you want.


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## tony.g (Apr 15, 2012)

@ Stuart - IIRC there was a post in this forum about a year ago, when an OP said that he could not find Strongboys in the US.
Maybe traditional props and needles could be used instead.

Steel beam probably best here rather than a timber header, but probably tricky forming a padstone on hollow CMU, particularly if concreted.

Agree; job for an SE.


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## stuart45 (Jun 20, 2009)

I was thinking of propping the ceiling with Acrows Tony, rather than using Strongboys.


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## tony.g (Apr 15, 2012)

stuart45 said:


> I was thinking of propping the ceiling with Acrows Tony, rather than using Strongboys.


Yes, you're right - I just noticed the S'boys first and they reminded me of that earlier thread!


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## jomama45 (Nov 13, 2008)

I've done a ton of openings similar to this in the past, and feel very comfortable doing them most of the time, but from your picture, there's no way I'd even think of making that opening without an SE visiting the site and drawing a detailed plan. The concrete roof/ceiling above the proposed opening is nothing to screw around with. I realize you're likely somewhere in Europe, so maybe $1500 is a substantial amount of money in comparison, but I would consider that a fairly good deal here in the states.

As for the header, it could be a steel beam lintel with block infill as described above by "md2lgyk", or perhaps you can source a pre-cast concrete lintel that is strong enough to span the opening. Hear we can still get most widths of pre-cast lintels between 40" and 144" long.......


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## Red Squirrel (Jun 29, 2009)

Propping the ceiling is one thing but you also have to prop whatever that wall is holding above the ceiling (ex: more blocks, or any other wall, which is then supporting the roof)

I would probably get a contractor for a job like this, but if I were to do it myself I'd try to find some thick steel L beams and cut a groove in the mortar on top to slide them in, do one side at a time. You'd want to add mortar and ensure that the L beam is truly supporting the wall and there are no gaps. Then the moment of truth, repeat on the other side. At this point I think it would be safe to start removing the below blocks. You could then add in a bigger beam or at very least tie the two together from the bottom. 

There is also the question of if the L beams you use are strong enough etc... So this is where things can get scary and why I'd leave it to a pro. 

I've been thinking it would be nice to have a door to get into my garage from the house, and I'd have a similar situation to deal with, and I decided that I'd leave it to a pro when it comes the time.


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## Bugman1400 (Mar 11, 2011)

I'm not sure you can mix wood (engineered or otherwise) with steel and concrete. IOW, you can support wood with concrete (ie most crawl spaces) but, not the other way around. It appears the walls and ceiling is concrete. I think you need an SE for sure. Otherwise, you can bet the concrete ceiling or whatever it is (ie garage floor) will crack. Forget what the contractor says unless he is also an SE.


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