Mortar problem building cinder block wall

[Muse]

I have been dealing with a bum wall in my garage and am at the stage where I needed to fix a missing portion of the foundation. My take now is that 1/2 the foundation for that side wall was cinder blocks in two courses with toppers. Someone decided that they wanted a door in that wall and they removed 3 1/2 cinder blocks, you can see where they tore them off of the concrete. So, to repair the wall I have to supply something in place of the missing portion of foundation (due to water intrusion from rains... runoff goes right to that area).

I was going to build forms and lay down some concrete when I realized that the space next to the remaining portion of the two courses of cinder blocks was just the right size to accommodate an extension 3 1/2 cinder blocks long in two courses (one on top of the other) with toppers capping the two courses. So, I scuttled the plan to lay down concrete and instead worked up a plan to build the cinder block wall as the needed extension to complete the foundation before reframing and applying siding.

Today was the day to do the cinder block work. I figured I pretty much had to do it as fast as possible using one 80lb sack of mortar mix before it went bad.

I watched a bunch of videos and read the instructions for the Sakrete Mortar Mix Type S 80lb. bag. I have virtually no experience with mortar, but I realize that it can be problematical in the same way as grout can be problematical. It might not harden properly unless everything's just right.

I bought the bag of mortar only a few days ago at Home Depot, so freshness was probably not an issue. The instructions are to use 5.3 quarts water with the 80lb. bag. I was paranoid I'd screw up, so I was super careful to use the _right_ amount of water. I didn't want to rely on my sense of what an appropriate consistency might be, I just don't know. I saw an online video or two that said the mortar when properly prepared should hang on the side of a trowel when held vertically and not fall off. Mine never got to that consistency, nothing like it. I added a little more water, it still just fell right off the trowel. I figured I better stop adding water and just do the job with what I had. I wasn't able to butter the sides of cinder blocks or toppers, the stuff would just fall off. Setting the blocks was a nightmare. I finally got it all done but now I have little optimism that the mortar will set. The garage has two walls that are solid cinder blocks and whoever laid them got the mortar right, it's like rock. I doubt mine will be like that.Figure it will me like sand, like a lot of the mortar in my house's brick walls that needs to be re-pointed.

The instructions say I have to cure the mortar or the project won't be a success. It says to maintain proper moisture and temperature. I have no control over the temperature out there in the detached garage or outside of it. Day temperatures will likely be up to 75 F and nighttime temperatures down to maybe 58-59F. The humidity will be around 50% maybe. I have taken a hand operated sprayer with water and misted the mortar joints around 10 times already in the 3 or so hours since I finished the job. The instructions said covering with plastic would help retain moisture. I guess I have some things that would help in that. Some tarps, maybe even plastic.

I measured the water exactly. In fact, I didn't trust volume measurements and instead looked of the weight of 5.3 quarts of water at 62F and it was virtually exactly 11lb, and that's what I added (measuring with a kitchen scale), but something went wrong, I couldn't butter any blocks with it and I know you're supposed to be able to do that.

What can I do here, what am I missing about this mortar and what can I do in the future to insure that my mortar involved projects don't fail (I have a lot of brick siding on my house that needs re-pointing). Thanks for help.

Edit: Just did a little searching and am reading a thread by someone who had a similar problem (but she was working in 40F. It was around 65-73F while I was working with the mortar and blocks). A guy said that if it was a mix you could be sure it was very lean. I think he meant that there wouldn't be a lot of portland cement in the mix. Another guy said "cheap mortar." Damn Home Depot, I trusted that their mix would work. It's crap, is all I can think. I would have gladly spent a few more bucks for decent mortar. Just damn! I had no clue I should beware of cheap mortar. I followed their instructions to the letter, got burned.

 

[MagnusTheBrewer]

Could have just bought premix.

 

[lxskllr]

I built up a window well using stone. It took a whole bag of cement to finally get it right :^D Too thick, add some water, too thin, add cement, too thick... :^D Live and learn. I later redid a sizable part of a friend's stone foundation, and it went well. Keep misting it for a couple days. A soaker hose would be easier. After that, let it set a week. If it seems like crap, tear it down and redo it. Cement's cheap, and you have time. I think it'll be alright once it cures though.

 

[Muse]

Could have just bought premix.

By that you mean maybe with water already added? Never heard of that before. What I bought was a premix, just lacked water. I'm wondering if they cheaped out... either portland cement or lime or both?

 

[Muse]

I built up a window well using stone. It took a whole bag of cement to finally get it right :^D Too thick, add some water, too thin, add cement, too thick... :^D Live and learn. I later redid a sizable part of a friend's stone foundation, and it went well. Keep misting it for a couple days. A soaker hose would be easier. After that, let it set a week. If it seems like crap, tear it down and redo it. Cement's cheap, and you have time. I think it'll be alright once it cures though.

I've been at the garage all summer, but haven't been going full blast. The thing is it needs to be done before the rains come or, well, bound to be a mess. Around here we typically have ~3 months with no rain, but that's going to end. September, it's a gamble. October, probably some rain. I was hoping I could get the whole thing done by Sept. 1. That means doing this wall/foundation fix, then tearing out the termite infested and rotted wood framing, replacing the framing with 2x4s on 20-24" centers, applying OSB siding and then Hardie Planks, paint. I have all the materials. Delaying another week or two scares me. I'm wondering if the framing and siding will firm things up enough where bad mortar won't matter. We are in earthquake country, though.

I saw in some posts from 2009 in another forum that it's the lack of lime that causes the mortar to not stick to a vertical or even upside down trowel. Maybe there is enough cement in the mixture (it's Type S, so should be rich in cement?). Maybe it will set up like you say.

Soaker hose? What's that? An automatic hosing system? I have one I bought last year for when I was OOT for a couple weeks. Even a nozzle on a hose would be easier than a hand squeezing plastic sprayer that I've been using this afternoon.

 

[lxskllr]

A soaker hose is a porous hose, usually a rough finished black rubber that releases a fine mist of water the whole length. If you have an old crappy hose, you could drill it, then maybe wrap it in rags to get a similar effect. Good way to use an otherwise useless hose.

 

[Muse]

I just tarped the wall portion I just built up. I had a 10'x12' blue tarp in the garage, in excellent condition. First I sprayed the wall I'd just built moderately with hose water, then tucked in the tarp with bricks and a 2x4 8 footer. Should at least stay moist overnight, will check tomorrow. I'm getting a lot more optimistic. The mortar seems at least semi-set. The stuff at the bottom is probably better. I was running real low and I used almost all of the stuff that had fallen during the work, wetting some as needed for the toppers. I was working pretty frantically because I knew that I had only about 90 minutes before the mortar would be setting up. I had timers there to monitor my progress (actually I went well over an hour more than the 90 minutes). I'm pretty sure that using the fallen mortar and adding in some water weakened the mortar used on top. My thinking as I got close to the end was that I didn't want to break into my backup bag, a 60 pounder just for the extra couple pounds I would need for the toppers. That bag will go back to Home Depot along with a couple of other items I won't be using.

A soaker hose is a porous hose, usually a rough finished black rubber that releases a fine mist of water the whole length. If you have an old crappy hose, you could drill it, then maybe wrap it in rags to get a similar effect. Good way to use an otherwise useless hose.

I do have another hose or two like that. I think my tarp with occasional wetting should keep the mortar moist for a while. Don't know if constant wetting is a good idea.

I have an automatic sprinkling system with a timer. It would be a hassle to set it up, though and I don't know that it would be as good as the simple tarp with occasional wetting option I'm using.

 

[paperfist]

Temp and humidity play a roll in mixing cement.

With the low cost of cement you could have played around with mixing it. It almost sounds like not enough water.

What tools did u mix it with?

 

[Muse]

Temp and humidity play a roll in mixing cement.

With the low cost of cement you could have played around with mixing it. It almost sounds like not enough water.

What tools did u mix it with?

I had gone to my local tool lending library (part of Berkeley's public library system, and they are walking distance from my house) and borrowed a mixing tray and mixing hoe (walked them home). They are what I used to mix. I did as instructions said and made a well in the center of the contents of the 80lb bag of Sakrete Type S mortar and poured in exactly 11lb of water (which is 5.3 quarts at 62F) and mixed with the holey hoe. Also borrowed a mortar trowel.

Yeah, I think maybe not enough water, that was my thought. But I also thought:

hmm... I mixed in precisely what they said I should and that wasn't enough... then I added some more and the mortar still just falls off the trowel. Should I really keep adding water??? Inasmuch as I don't know mortar from oatmeal I figured I better not and just do the job with what I have and hope it works out somehow. I had to shove mortar into all the vertical cracks with a pointed trowel, a real PITA. As I got to the end, I resolved to post online looking for help/answers (i.e. this thread). After cleaning up some and putting my tools away I finally got off my feet and started this thread.

When I brought the tools back to the tool lending library in the evening I mentioned my problems with the mortar. The guy working there said he thought I had too much water in the mortar. I asked why, I'd measured exactly, and he said the humidity in the air. I said that couldn't be unless the mortar had absorbed moisture from the air while in its bag. Doesn't seem likely, I just bought the bag. The powder in there seemed dry enough. I think it was just crappy mortar. Man, if I'd had any hint that the mortar they were selling was poor quality I'd gladly have paid 3x more for better stuff. Or more! I've put a lot of time, work, money and thought into this project. To jeopardize it by trying to save 10 bucks is insane. I just didn't know.

 

[MagnusTheBrewer]

Premix is ready to use right out of the bucket. No mixing.

 

[Muse]

Premix is ready to use right out of the bucket. No mixing.

Aha. Were I to be where I was last week and knowing this, I would have bought premix. 5 gallons would have likely been enough. Didn't know that stuff exists.

 

[paperfist]

By no means am I an expert, but I've poured or helped pour a bunch of slabs in my time along with fence posts. It's an imperfect science and I've always had to adjust water content from bag to bag. Sometimes it comes out like peanut butter, sometimes soup.

It's just a matter of adding more water or more mix.

 

[lxskllr]

IDon't know if constant wetting is a good idea.

I don't think you can make concrete too wet. Structural concrete gets covered in burlap, and has soaker hoses running for a week or so. It slows down the cure(I think) and reduces cracks. It's not really my thing, but I work around the periphery of concrete work all the time.

 

[Muse]

By no means am I an expert, but I've poured or helped pour a bunch of slabs in my time along with fence posts. It's an imperfect science and I've always had to adjust water content from bag to bag. Sometimes it comes out like peanut butter, sometimes soup.

It's just a matter of adding more water or more mix.

Yup, understood. Problem was I had only watched videos, that was my experience and I had already added more water than the instructions indicated. I am sure now it was too dry by quite a lot but I wasn't sure then that I wasn't adding fuel to the fire by adding more water so I completed the job with the too-stiff mortar. It was a nightmare. But I think it's setting up pretty well now after curing for almost 3 days dampened periodically and very well tarped.