Replies

1. 
   BoJangles | Aug 16, 2009 01:50am | #1

   What size are the block?   How high is the block wall?  Are any of the cores filled now?

1. 
   markjs25 | Aug 16, 2009 01:58am | #2

   8" block; block wall about 9' high; I don't know if there are any filled cores, although I completely demoed another partition; it had a bond beam on top but no full cores. It was a non bearing wall though, so don't know for sure if this one's the same. Another question; if I determine that there is a bond beam course at the top of this wall will that carry the floor and I just have to worry about the block itself? The bond beam I demoed was mortar not concrete and was reinforced with smooth rod, 1/2 or 5/8 inch so I don't know if I should trust it even if there is one.

1. 
   BoJangles | Aug 16, 2009 02:54am | #3

   How are you planning on trimming out this opening?   Is this block exposed and painted on both sides of the wall?

   You are right...a beam reinforced with smooth rod is not too dependable!

1. 
   markjs25 | Aug 16, 2009 10:13pm | #8

    

    

   BoJangles; yes the block is exposed and painted on both sides. There is an existing opening similar to the one I need to make that is trimmed with wood jambs and casing, so I will try to match it as best I can. There is no lintel in evidence however so I assume it is a bond beam. But I obviously can't do that on a retrofit so I figure I'll just paint the exposed steel the same as the block and it'll be fine- it's not a custom home after all:)

1. 
   BoJangles | Aug 17, 2009 01:53am | #10

   We have done them almost exactly as Ponytl described.   You can use an 8" high x 4" wide structural or wide flange I-beam.  These are both available in different web thickness.  You really don't have a lot of weight up there, so a web of 3/8" is more than enough to handle that.

   I would size my opening according to block increments.  If you took out a row of block extra above the window opening, filled the cores on the sides that bear the beam and then slid the I-beam into the header opening....you can lay 1 5/8" blocks right back in to cover the beam and maintain the clean block look of the wall.

   We usually weld a 1/8" or 3/16" plate to the bottom of the I-beam to support the row of block you are setting in to cover the beam.   This makes for a clean bottom on the header.

   Use whatever you want to trim the rest of the opening.

    

2. 
   Robrehm | Aug 16, 2009 05:17am | #4

   I would double check with a structural person but the last one we did that was similar we had 5/16 4x6 angle on both sides

   "this dog may be old but he ain't cold. And he still knows how to bury a bone."

   Lattimore

    

   http://www.rehmodeling.com

3. 
   CapnMac | Aug 16, 2009 08:19am | #5

   Well, many of your questions require asking the Authority Having Jurisdiction in your area.  They may well require you have an engineer write the spec for such things.

   Now, from experience, 1/4" angle is better than 3/8" as that lets you squish a thin line of mortar in.  But, some spans are better with 3/8" as that is a world simpler than when the EIT are the engineers writes the spec to read 5/8" which wants dragging the EIT down to the site to plane 2/8" off of all the blocks to be supported.

   Old rule of thumb I used to use was lintel length = opening + 2 blocks if solid-filled jambs; + 4 if hollow.  But, that was using 3x5x1/4 on both sides, too.  But, I'm just text on the internet, not an engineer.

   Occupational hazard of my occupation not being around (sorry Bubba)
1. 
   Matt | Aug 16, 2009 01:52pm | #6

   >>Old rule of thumb I used to use was lintel length = opening + 2 blocks if solid-filled jambs;... <<

   Is that the thickness or the length of 2 blocks?  In other words are you saying you want 8" or 16" of bearing on each side of the opening?  16" seems a little excessive but what do I know?...

1. 
   CapnMac | Aug 16, 2009 11:06pm | #9

   want 8" or 16" of bearing on each side of the opening?  16" seems a little excessive but what do I know?...

   Precisely.  Masonry loads "pass down" in big fat 45º angles, so whole units are better (or are just easier to remember dimensionally, at least for me). 

   Now, a hollow (unfilled) block, all ot that lintel load is bearing on the rather thin web of the block, spreading that load out over two blocks just better as a rule. 

   But, my caution on checking with engineers and AHJ still applies.  I've had to "sawtooth" jambs out to fit solid-filled jambs up, then crib to support header blocks with bar in them (and a triangular hole of removed block over that), because that is what the AHJ required of the engineer.

   In case that seems a lot, consider the opening this way.  Get a photo that shows the joints.  Start one block beyond both jambs and follow up in a 45º line until the angles meet or you reach some other form of support.  Count the blocks in the triangle and cipher them at 40-50# each--16 40# block are a quarter ton.Occupational hazard of my occupation not being around (sorry Bubba)

4. 
   ponytl | Aug 16, 2009 06:02pm | #7

   this is how i do many.. with spans larger than yours... but with the load you may or may not have... it's how i'd do it... and never worry about it... prob overkill

   I use my chainsaw with the diamond blade... plunge cut like below
   I---------------------------------------I
   I___I...............................I___I
   I I
   I I
   I I

   the ---- and the ..... are at the joint the ... usually isn't required to be cut to remove the block.. the "I" cuts and in the corners are the ones i really like to use the chainsaw on because i can plunge cut and get good clean cuts..plus it's a thicker cut so the demo is easier..I then remove the blocks and i slide an I-beam or a tube... to become the header for 8" block i want a 6" high header... so that i can place it in the T put mortar on top and then jack/ wedge...or just force it up so that the block above it are now sitting in a bed of mortar... the perches on each side i fill with mortar... if the joint is thick enough i mortar in brick to fill the gap between the steel and block...

   i have done spans up to 12ft like this brick & block... everything stayed in place while i cleared the way for the steel to go in with no temp support... maybe i'm lucky... but it's always worked and I have peace of mind knowing what i put in is maybe overkill but... it ain't going anywhere...

   I usually find the steel tube 3/8" wall at a sign company... where they usually have cut-offs from large sign posts... or a sign they have removed... but even a steel co... might have a drop... anything less than 10ft is usually a "drop" for them

   p

5. 
   markjs25 | Aug 19, 2009 03:11am | #11

   Thanks to everyone for their advice! Y'all have a good day.

   Mark