# split face block installation



## nrnik (Apr 18, 2015)

Hi


Any ideas about split face block wall installation? is there any manuals?
how to reinforce a split face block wall?
horizontal and vertical rebars? sizes and spaces between blocks and rows?

Thank you in advance.


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## griz (Nov 26, 2009)

nrnik said:


> Hi
> 
> 
> Any ideas about split face block wall installation? is there any manuals?
> ...


Any ideas about split face block wall installation?...is there any manuals?

*A skilled Mason installs block. It is not something you can just watch a video on and then go lay block. Accuracy and aesthetics can be difficult to attain and maintain without experience. *

how to reinforce a split face block wall?
horizontal and vertical rebars? 

*Rebar is used for reinforcing. Size and location are determined by an engineer when the design of the wall is completed.*

sizes and spaces between blocks and rows?

*If you are asking about mixing styles of block in a given set of courses, this is an appearance issue and not a structural issue. 

*


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## heavyc (Jul 2, 2013)

Where are these questions going? Consult a mason. This is a professional forum not DIY?


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## concretemasonry (Dec 1, 2006)

If you are dealing with a good supplier, there is no difference between plain units and split face units since most of the same units are available (almost identical molds). The problems will be odd coursing (1/3 or 1/4 bond) and some details at openings or odd corners (not 90 degrees). Generally, the same shapes should be available in plain and split face but hopefully you did a good take off and and got quotes for special units or came up with details to minimize costs.

I you are dealing with a low end producer (cheap), you could plan on wearing out a lot of saw blades or even saws in addition to much higher labor costs.


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## heavyc (Jul 2, 2013)

Why would there be 1/3 or 1/4 bond? FMI? Thanks. I've never laid anything but 1/2 bond. FYI.


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## concretemasonry (Dec 1, 2006)

heavyc -

The odd bonds are used for architectural purposes and many can qualify for "other than running bond - 1/2 lap" for structural design purposes. - Not all "split face block" have a single 8x16 , 6x16 or 4x16 face. Some may have one or more vertical 3/8" scores at various locations, heavy vertical "flutes" or even 2" wide vertical smooth strips. There is an amazing number of scored split face patterns that have been used.


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## heavyc (Jul 2, 2013)

I've done work with double scored. So as you know or can calculate that is 3 equal segments approximately 4 5/8". They are still laid half bond and joints raked. I've used 4" for veneers and they also lay 1/2 bond if your PM is on his A game you are fortunate enough to have returns. No cuts. To date no 1/3 or 1/4 bond? I've done radius walls ending in odd angles not always 45°to the radius no big deal cut what works. A split face is nothing more than a typical block with a different finish. There is no difference in bonding or reinforcement. Surely there are Architects that push the envelope to stand apart from the norm. But let the photo posted be the guideline nothing special just 8" typical split face. And I'm still questioning what this post is doing on this forum.


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## jazzwillie (May 15, 2015)

Unless you have a 24" nominal, I've never seen structural splitface block you could lay anything other than a half bond and get your rebar to work properly. Not that you couldn't cut zillions of end, and centers out to achieve it, but from a factory unit, you could only do it on a veneer or 24" long splitface block.


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## concretemasonry (Dec 1, 2006)

jazzwillie -

Apparently you are talking about a unit that is not the size (6",8",10",12" or 14" thick) of standard concrete masonry units. A 24" long unit is a big problem on most jobs.

We made over a million units a year in many colors and shapes.

The preferred shape was 16" long with open ends and two webs at 8" on center to work for reinforcing vertically and grouting. For horizontal reinforcement, we made both open core cut down bond beams and conventional bond beams with no longitudinal divider. In addition, we made the usual corner units and flush end units for around doors and windows.

I think you could find a good supplier somewhere in your area. We also sold those blocks to our competitors and they resold them. We would not sell specialty block to contractor that was using someone else's regular block but would sell to our competitor. Block are cheaper than extra labor.


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## heavyc (Jul 2, 2013)

These are what I've always laid. Score the face all you want still same animal.


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## concretemasonry (Dec 1, 2006)

heavyc -

You are right that this thread really is not a structural problem, but when you get into reinforcing, it does get structural if you want to get the most of the block wall at a good price.

It is ironic that the drawing you posted looks exactly like my drawings from years ago when I had to show over 400 different size and shape units. Too bad the block shown does not match the drawings. The photo is for an old style "pear shaped" core unit with a sash groove and not square cores that are in the drawings.

It interesting that the drawings showed what is apparently straight cores with a minimum of 1-1/4" face shell. Many producers also make a very similar unit with the top face shell flared inward to give a 2" wide mortar bed to minimize mortar slop and keep the cores free of a lot of the slop mortar that causes problems with grouting and requiring clean-outs. This was at the request of contractors that also wanted the block palletized with the top up for easier handling. - Little things to keep the labor cost down.


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## jazzwillie (May 15, 2015)

I'm well acquainted with our local manufacturers. What I was saying is that laying a 2 celled structural splitface on a 1/3, or 1/4 bond splits the cell and inhibits the flow of grout, without cutting ends and centers out and grouting additional cells for each vertical reinforcement location. 

Regarding 24" long units, they are gaining steam in our area in back up. Not really exterior applications.


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## Fouthgeneration (Jan 7, 2014)

I some ways split face CMUs require higher levels of craftsmanship because they are not the nearly exactly the same dimensions.

Judgement must be used to set limits for the concavity or convexity of the the split face... and of course the sloppy break planes can make building an attractive wall nearly impossible. many cheaper units will require the laying of the smooth face unit side out of plane and or plumb to achieve any sort of grossly plumb split face wall.

Further more some plants have real issues keeping a constant ratio of aggregates, other ingredients, & curing leading to poor q.c. on color matching day to day production runs.
Many times specials are obviously differing shades of color from the stretchers. 
I'd suggest laying over the wall to less skilled/clean laying mason gangs.


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## heavyc (Jul 2, 2013)

Couple more in use today. Not sure why these are considered old. Because we are laying them on Bragg now.


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## Fouthgeneration (Jan 7, 2014)

The allowing the use of 100 % jamb face block for a ACOE job shows how technology can disappear much faster than it was created.

Smooth jamb ends will always test weaker in torsion and shear.

They are easier to demo though.


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## jazzwillie (May 15, 2015)

I've recently become a fan of sandblasted block. It has what I consider a happy medium between split face and smooth block, and a much more consistent size. Another I'd like to work with is what is locally called a Stri-faced. http://oberfields.com/images/masonry2013/248.jpg Has that texture of a vertical score brick. Like a Bowerston #1450. But like most different things in masonry I may never convince an owner that for just a little more they could have a unique feature on their building that will make theirs stand out.


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## CJKarl (Nov 21, 2006)

Our local guy Westbrook Block, got in to the sandblast/ground/polished finishes about 10 years ago and has been doing really well.


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## concretemasonry (Dec 1, 2006)

The "sand blasted", "stri-face", "ground face/burnished", "random score" and combinations of these are not new and have been around for 30 to 40 years as far as I can remember, but they may have started earlier, but were very localized.

The use of these can be combined with one treatment on one side and another on another. - How about sand blasted, ground face, or scored on one face and another treatment on the other face. I have made scored spit face block on one side and sand blasted scored on the other face. In several localities is saw them combined with block that were made with 2 or 3 colors of concrete mix in the same block.

CJKarl - I though Paul made some of those back in the late 1980's when I was in CT.

There are so many different techniques processes that are localized, but never spread until many block plants became part of the large or international owned corporations.


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## dom-mas (Nov 26, 2011)

figuring out steel requirements for block isn't all that difficult if you have the right charts. In a seismic zone 2-4 the steel requirement needs to be 0.002% of the gross cross section of the wall, with at least 1/3 of the steel being in one direction, (no more than 2/3s the steel in the other direction) horizontal OR veritcal. Do the calculations and go to your rebar charts and find whatever size of steel you want to be using and the placement...so a #20 piece of rebar (you guys call it #6 I think) could be placed every 4' or a piece of # 10 (#3 in Imperial) rebar could be placed every 16" (so long as it met or exceeded requirements (I can;t remember what it is but there is also a maximum spacing allowed...4'?). Same goes for horizontal re-inforcement but I know in my area wire re-inforcement is counted (not to exceed every 2nd course) but according to others in their area it isn't. 

Anyway it's not that tough if you have the proper charts

Oh and this only applies to buildings within the bldg code...here 6000sqft or less and 3 stories or less


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## superseal (Feb 4, 2009)

Fouthgeneration said:


> I some ways split face CMUs require higher levels of craftsmanship because they are not the nearly exactly the same dimensions.
> 
> Judgement must be used to set limits for the concavity or convexity of the the split face... and of course the sloppy break planes can make building an attractive wall nearly impossible. many cheaper units will require the laying of the smooth face unit side out of plane and or plumb to achieve any sort of grossly plumb split face wall.
> 
> ...


Our local plant will sell us seconds for a lot cheaper and my brother agreed to use them on his detached garage project.

We mix the terms split face/rock face a lot around here but technically it's split face.

The bastards are heavy and unruly...normally set our corners and string them on the inside. 

I hate laying these units, but they do look nice, even seconds. We didn't have enough of the white color so we mixed in grey for the splash zone.


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