Laying Cinder Block.....
 

I am going to build a shed using 8x8x16 cinder block.

I was going to build a footer for the shed, and probably not pour the floor until later, if ever depending on how I use it. I am thinking a 20' x 20' dimension with a 10' high wall. For strength I was planning on using rebar and pouring every other channel in the cinder block.

I am pretty new to this game. Has anyone laid their own block before? Any advice that anyone would care to provide on the matter? I figure the main requirement in laying block is patients and of course keeping the wall plum and level as you go.

Since I am not living in this structure I plan to use it as practice before I build our house :)

Dave

Re: Laying Cinder Block.....
 

you can do it but you will find that it is much harder than it looks.
Buttering the ends of the blocks is tough,
the mortar will keep falling off when you try to set the blocks unless you have the mix / water ratio just right.
If you can find a mason who is out of work to help you it would be well worth your while,
again, laying block may look easy but it's not.
I'll bet at the end of the day you will be thinking: That's all I got done! geesh

Re: Laying Cinder Block.....
 

It's hard work, but not complicated. There is a learning curve.

first off, get the footing right. Straight, level and strong. Plenty of rebar. I like to have a keyway set into the top, using a beveled 2x4. That makes it easy to keep the blocks centred on the footing too. There's a neat type of reinforcement for block walls that looks like steel trellis. One of those every few courses will probably provide far more strength than filling the blocks.

Tricks .... well, one useful 'trick' is to always pick up the exact same amount of mortar on your trowel. You can always all a little, but if you can get a rythme going, you move ahead pretty quickly. Get helpers. one person on the mortar, one person moving blocks to you. you buttering and laying, and one person eyeballing the alignment (usually the same one responsable for keeping you supplied with mortar. If you have to stop buttering to move blocks, or fetch ... it`s gonna be a long day. Remember, with mortar, you`re on a clock.

Re: Laying Cinder Block.....
 

Re: Laying Cinder Block.....
 

8" block is the easiest to work with. Also, using an even module of 4' helps ( like your 20' ) Will take exactly 15 block per course ( 20' x 3/4 ), which means no cutting.

Your footer should be at least twice the width of the block ( and I like 24" myself.....common width of a backhoe bucket ), and 8-12" deep depending on your soils.
Frost line shouldn't be an issue in FL.

1. Build the corners first. Lay them up about 6-7 courses, and make sure you lay the first course of the first corner in the same direction as the first course of the second corner, so you work out an even number of block along that first wall......IF you turn one of those two corners the wrong way on that first course, you're gonna end up with a 1/2 block in middle of the wall.....so watch your "bond".

The corners are where 90% of your efforts go.....lay those first courses level, plumb, and straight to each other ( use a string line on the first course pulling to second corner ).

2. Once you have at least two corners done, you can set the level aside and simply "run the line".....use a string line between courses on the corners to keep you straight and level. With experience, you will learn to get the same amount of mortar on the "head joints" ( about 3/8" ) so the last block in the center goes right in with the same space as the rest.

3. Once you get all four sides up to that 6-7-8thth course, you will have to scafold and repeat the process.

Pouring every other web with rebar is probably overkill unless you are backfilling dirt against the wall.....which you probably aren't in FL......that is the problem with most block, is side pressure....they don't take it well. Compression strength is huge with just the block alone, but filling about every 4th web and re-baring it will give you all the side strength you'd need for high wind conditions if you live in hurricane prone areas ( you might check local codes to be sure.....also for roof tie downs tied into that concrete )

A lot of it is just experience you can't get from reading anything.....best thing you could do is go find a house under construction, take coffee and ham biscuits with you and talk to the masons.....tell them what you want to do, and see if they will give you a few tips, and then watch them for a couple hours.....that will do more to teach you than anything.

Re: Laying Cinder Block.....
 

Oh yeah, don't forget to use a story pole on the corners as you go up. Build your corners up several high, then use a string between layers to keep your height.

Andy beat me to it, also alot more specific.

Re: Laying Cinder Block.....
 

Finally a topic I have much experience in. 1st) there are two different kind of blocks, haydite and concrete. Concrete is for sub grade and haydite is for above grade. Haydite block are noticibly lighter. 2nd) 8" block is actually 7 5\8" x15 5\8" x 15 5\8".The joints should be 3\8" both bed (horiz.) joint and head (vert.) joint. 3rd) premix mortar sucks as far as getting it to stick adding a bit of masonry to the premix helps a lot. I have found after 1000's of union blocks that it is easier to butter blocks on the wall and just smear the block that is on the board. When I say smear think like a peanut butter sandwich just a layer for the buttered block thats on the wall to bond to the smeared block on the bench. Corners are always laid first as Andy said. If the corners are laid well .the string drawn banjo tight, Lay to the line and it will turn out fine. Bond tool co. has good books and info for learning.

Re: Laying Cinder Block.....
 

Can only add a couple things to what was said. Loads of great advice. I had to build a 200' 4' high wall. In VA, footer had to be 21" down, was a pain. I too started to fill with concret, but gave up, was not necessary, and cost ALOT more in $ and labor. I do things overkill alot, so in footer , I but a half inch rebar sticking up 6 inches every 6'. I did fill those , where the rebar stuck up with concrete.( for some reason was afraid that only being 4' high, needed more than just weight to 'stick' to footer) I found the most important thing IMO , was the morter mix ratio, given it was in mid summer and 95 degrees outside, blocks where hot and sucked moisture out of morter mix real quick, so had to play with sand/portland/h20 ratios. Wall turned out perfect, too perfect, if you know what I mean. Have looked at many being built, and they throw them up real quick, not every block 100% level, but every few togather, were real close to level. If mix too dry, you will set it to hard and wind up pulling and resetting. My perfect wall was covered with (veneered) natural stone and could not even see after words.

Re: Laying Cinder Block.....
 

I would put at least (2) # 5 bars in the footing...

Re: Laying Cinder Block.....
 

Couldn't have put it better myself. I once helped repair a wall my cousin built without decent footers. Let me tell you, I could have built three walls in the time it took to repair one.

Re: Laying Cinder Block.....
 

everything that has been said is right on...esp the footing smooth and level...corners...story poles...etc

i wanted to add a couple of intresting options

#1 its good to add some horizontal bond beams every 4' of vertical height or so those are a U shaped block you put a rebar in and fill with concrete around the building at a minimum you want to add ladder wire reinforcing at prob every 3rd joint vertically

#2 if you have a good block maker that makes uniform blocks i have seen many walls DRY STACKED.....in other words mortarless...you still put in the vertical rebar cells and the horizontal bond beams and concrete fill....most of the time Dry stacked walls are covered on the inside and outside with another product such as EFIS outside ...Drywall inside

#3 concrete blocks are NOT water proof at all ...plan on buying blocks with sealer in the block AND a spray sealer on the outside as a minimum

#4 consider how you will want to insulate the wall now or in the future...foam filled...foam inserts..vermiculite..etc.....cause blocks are not energy efficient at all

Re: Laying Cinder Block.....
 

I'm an architect, what do you specifically want to know?

Re: Laying Cinder Block.....
 

How do you like your coffee?

Re: Laying Cinder Block.....
 

LOL That's pretty funny.

Re: Laying Cinder Block.....
 

Black no sugar

Re: Laying Cinder Block.....
 

If you don't get you project layed out and squared up before you start you are going to have all kinds of problems. Building an out of square building is a nightmare.

Re: Laying Cinder Block.....
 

I'm a Construction Project Manager/Engineer/Coordinator and most of my work is undoing the idiocy of the architect. Listen closely to the those offering advice on masonry, ignore the architect.

Re: Laying Cinder Block.....
 

I did a quick search on U-Tube. I'm sure there are other and better videos to give you some guidance.

EDIT: OK, see feedback below Right, this is a strange technique, if you can call it that. Sorry, I just grabbed the first video that had the right title to use as an example, didn't watch it through.:signs14:

Re: Laying Cinder Block.....
 

SLV>GLD I'm a Construction Project Manager/Engineer/Coordinator and most of my work is undoing the idiocy of the architect. Listen closely to the those offering advice on masonry, ignore the architect. you didn't need to mention you're a biggot as well. You profess to have knowledge in construction, yet when a guy asks for help you keep your mouth shut only to criticize another making an offer to give the help you are not prepared to give.

Re: Laying Cinder Block.....
 

I am not sure what type of half-ass mason the guy in the you tube video is, but I have never seen anyone build like that. TN Andy gave you the best advice. I have always rented a small backhoe to dig my footers. Down in FL you could dig it by hand if its just sand, but it will take some time and the footers have to be square or the block will also be out of square.

Re: Laying Cinder Block.....
 

Have you considered dry stacking, with a surface-bonded adhesive that is supposed to form a watertight membrane as well?

Re: Laying Cinder Block.....
 

omg......what ever you do dont even think about doing what is in that youtube clip....

starting with a footing

#1 it needs to be wide enough to lay blocks on and i would guess that to be a minimum of 12" ...but like Andy said just use what ever size bucket you get with your backhoe...you need to make sure you have good dirt in the bottom of the footing hole..a easy test is to take a piece of 1/2 inch rebar and see if you can push the 1/2 end into the soil with light pressure it shouldnt go more than a inch or so into the dirt. if the dirt is bad you can stick a piece of rebar in forever

#2 the depth of the footing needs to be below your local frost line.....in our part of the country it is 24" deep minimum
#3 i would subjest the minimum thickness of the footing to be 12" thick
#4 i would subjest a minimum of 2 runs of #4 or 1/2" diameter rebar contiuneous in the footing...we put these up of pieces of brick so they are suspended in the concrete
#5 of course the footings need to be layed out and square ..the wider the footing the more play you have to get the building started right
#6 the concrete you pour in the footing needs to be flat and level...any deviation from flat and level will be a headache and much more work later so its important to do a good flat level footing top surface
#7 how we get a flat level footing top to lay block on is to drive verticle rebars ever few feet and use a laser level to make sure the tops of the rebar are perfectly level then when we pour the concrete we screed with a board between the perfectly level rebar tops ...and float (wood trowel) the top of the footing out ...this will get you within a 3/16 inch or so...if we are doing a dry stack we will actually steel trowel the footing top like a floor slab to get it really close
#8 once the concrete drys we use concrete nails to lay out a perfect square and lines on top of the concrete with nails and chaulk lines
#9 after that you can start laying the block in what ever method you choose but if you dont get the footing level you will have to use mortar or saw blocks all the way around the first course to make up for your mistakes on the footing because the top of the very first course should be string line perfect

#10 i almost forgot you will want verticle rebars protruding from the footing going up into the block cavities to start your verticle cells ...there are two good ways to get those in ...one is to after you trowel very thing out and the footing is still somewhat plastic you can do a layout and have precut rebar pieces to just push down into the footing at exact points......or you can drill in rebar dowels into the footing later when you do the wall layout

hope this helps

Re: Laying Cinder Block.....
 

Just ribbin'. :wink: I had my own firm for 15 years.

He did not write any advice.

I would delete that video...

Don't ever do this. This defeats the whole purpose of encasing reinforcing in concrete. Water seeps in and rusts rebar, not good, especially in sandy soil. This should be done with wire ties or pre-made wire stands you can buy at a masonry supply store.

Re: Laying Cinder Block.....
 

Awesome!

Guys I can't thank you all enough for your input. I am dead set on doing this myself because I plan to build my house this way and figured I would rather screw up my shed :D

To review this is what I absorbed....

Measure, Measure, Footers, Footers, 90% effort to corners and then lay from there.

Andy, Great thoughts on the 4' feet increments. This was in part the reason why I choose 20' x 20' thinking this would reduce some work so good too know my logic was sound.

Honestly, everyone here has contributed quite a bit and I can't thank you enough.

Once I start the project I will take pictures and post my progress. Hopefully this will allow some of you to contribute as I go and keep me out of trouble!

I am going to go back and slowly reread this thread so I can take it all in.

Thank you,

Dave

Re: Laying Cinder Block.....
 

Block layers are usually built like bulls, but I once knew a skinny old man who used a very different method that did not require boosting blocks about as much. He would stack blocks two or three high, kicking them into alignment as he went, and then he would pour concrete down the holes and ram it in with a stick. No mortar. That would horrify an inspector, but his buildings stood as long as anybody else's.

Re: Laying Cinder Block.....
 

The problem with that method, and using the surface bonding plaster/mortar is block aren't all that uniform. So when you dry stack a pile of blocks, they won't be level or plumb.

The surface bonding mortar comes with a whole bunch of little plastic shims to stuff in the joints to get level/plumb, and it takes more time and fussing around with them than it's worth ( unless you are just going 3-4 courses and it doesn't really matter about level/plumb).

That REALLY about all the mortar actually does on block laying.....level out the courses and let's you achieve a fairly plumb wall as you go....it does add a little sheer strength, but it doesn't take much side pressure on a block wall to show you just how little it adds.

As I said, most of block strength is compressive ( down ), not sheer (from the side). So if you have a NEED for sheer strength, ( and many times with a simple, out-of-ground building, you don't ) grout with concrete along with vertical rebar.

Re: Laying Cinder Block.....
 

there are many acceptable methods of suspending rebar in concrete the least expensive and most common method is what i have described.


Feel free to research the CRSI (concrete reinforcing steel institue) manual or site specificly in reguard to "bar supports"

I am fully qualified to make the statements i made, if you have any qualifications to make the statements you made, i would be happy to enter into a debate as what form of Bar supports are the most appropriate for any specific configuration and ussage.

I also will gladly and humbly admit if i have errored in my advice in any way, I will also be happy to cherry pick and critique you'r posts if you wish to take the time like i did to put together a comprehensive step by step post to help the guy.

Re: Laying Cinder Block.....
 

:4_1_72:


LOL No kidding, way to poke a needed jab into (a)architect ( no one specifically, but the industry as a whole)

Re: Laying Cinder Block.....
 

+1......dry stacking works and is easy but isnt pretty so it needs covering inside and outside


Adding to the subject at hand

you also need a horizontal bond beam at the top minimum to tie your roof and walls together in addition to the verticals

going to the masonry institue website would provide some added information and some masonry sections and details to put pictures to the words that have been posted on here, this is a link to a standard details list you may wish to look through for what is applicable IE details for lintels over doors etc http://www.imiweb.org/design_tools/m...etail_list.php

Re: Laying Cinder Block.....
 

My advice
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for what it's worth
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Hire an out of work Block Mason.

Re: Laying Cinder Block.....
 

The concrete will cure and shrink away from the brick allowing water in or the brick will wick water to the steel. You could get away with bricks and indeed they are allowed under CRSI specs. But experience and practice say otherwise and most standard specs I ever read over ride CRSI. I would not recommend it in a tidal area or flood zone and no one carrying liability insurance should specify such. In sandy soil you have to build a form for the footing anyway so all bars are tied through the form. If your making a grade beam and doing bars top and bottom this is especially critical as the bottom bars are in tension and count the most. I built over a hundred buildings as G.C. or architect and most were near salt water and low water tables. Before that I worked for an engineering firm and was involved in large concrete projects such as water treatment facilities, concrete log flumes and ferris wheel/amusement footings, concrete breakwaters etc. I am retired... and I can't believe I just read a specification. First time in 4 years...ugh.

An example spec found on Google. I would post one of my own but they are on an old work computer and have my name and old address all over them anyway... Section 8, first paragraph, last line.

I did not mean to offend but impart greater wisdom on the whole.

Sorry to step on your thread Dave.

Re: Laying Cinder Block.....
 

I also do not mean to offend or over engage in a debate over a insignificant issue.

but since you have mentioned your qualifications and stated your point of view and specificly discounted my original post i will state my qualifications (which are current)(includes over 30 years experience)

I own a design build construction company licensed in 42 states including florida and california and since i personally carry the licenses i passed the tests involved. As part of my company we are licensed engineers carrying seals for all diciplines in 14 states with reciprocity availible in most others.
I am a bonded individual that regularly builds both low and highrise industrial and commercial structures including heavy highway and bridge. My education is as a civil eng and BADM as part of my company i regularly employee as many as 100 masons. I am a member of the ASTM...AISC...CRSI..IMI...AIA... and other pertinate proffesional organizations. so i do feel ultimately qualified

as to the comment..about the water filtration and intrusion..if you truely feel water intrusion is a issue you should have been more specific and shared more of your wisdom and specified...epoxy rebar..and sand bearing plates on the Galvanized or SS high chairs etc which would be appropriate for the condition you are describing.... i was giving the questioneer a general minimum specification and generic guidelines for a layperson to work from to create a shed in his back yard, you can create all kinds of special circumstances to justify your post if you wish. all i did was give a generic guidelines for someone to consider, to help him on a project, my posts were in accordance with the governing orgaizations i posted, i can also post a specification that states the opposite of yours and allows brick bearing. but i chose to post from the governing organization.

please give consideration to the intent and contex of a post before you choose to cut and paste and discredit others posts

Re: Laying Cinder Block.....
 

This sounds like good advice from someone who has been there.

Re: Laying Cinder Block.....
 

Whoa, folks.

I come from a long line of accredited SOTP builders/engineers -

SOTP, of course, is "Seat Of The Pants."

And I started learning the trades when I was about 12 years old.

I disrespect neither side of this caterwaul, although being nauseously

Familiar with each other's complaints about each other

Over the last 35 years.

My point?

If and when TSHTF, those who have the hand skills, whether

Apprentice or Master, will have better success

With flat out building what they need at speed.

Than P.E.'s (those with engineering degrees)

Because the work will be on the ground and

Not subjected to the byzantine paper trail

Of obtaining "Permits."

This is not to say that an understanding of engineering is bad.

"When the going gets weird,

The weird turn pro."

- Raoul Duke -

Use what you have to best effect........


scyth

Re: Laying Cinder Block.....
 

As to the discussion of putting the rebar on bricks or stirrups or suspending them between the forms. I have been a concrete contractor for 22 years and on a project this small I would just pour the concrete in the footing and imbed the rebar by hand just lay it on top and push it down .

Re: Laying Cinder Block.....
 

MorganTheGoat & TTAZZMAN,

I am enjoying the discussion as a layman so no worries about the debate! As Bob681 pointed out I think this is a pretty small project so there are many considerations that likely will not apply. Of course I don't have enough experience to say that for sure but that is my hunch.

I will just be careful to keep the kids away from the shed just incase the thing crumbles down the road! :D

By the way, I will post pictures of the construction process so you guys can make sure I don't make any serious mistakes.

As someone posted earlier in the thread, I will likely dig the footers by hand since my soil is a nice pact sand with only about 9'' of OM at the top.

Dave

Re: Laying Cinder Block.....
 

I would seek some consultation on footing width and reinforcement from a local source that knows your "soils"

you probably need to go see your local building regulations department before you do anything as they may have minimum construction standards you would want to follow