Masonry cement gone bad?

[Tig]

I had six bags of masonry cement left over from bricking my place. They have been on a skid in the garage for the past 20 months. Dry, with a plastic sheet draped over them, but it is quite humid here in general.
I'm installing a corner shower and the instructions said to set the base in a mound of mortar for added support. So I opened a bag, it had a few soft lumps but no hard crumbs. Mixed it 3:1 (didn't have any portland to add) and I built a base for the mound yesterday Today I have that uh oh feeling. It did set, sort of, but stray lumps simply turn to dry powder when pinched lightly. It's been 20 hours, the mound is 3" high.
In retrospect I'm quite annoyed with myself on several levels. If someone else had built a 3" mortar mound as a base and used old left overs to boot, I'd be hard pressed to not roll my eyes.
I'm going to avoid mirrors till I get this done properly.........

 

[dave1949]

Maybe give it another day? Watched pots never boil and watched mortar never sets. Anyways, you will know for sure in another 24 hours. Until then, relax, it is out of your control. If it doesn't harden, it won't be any more difficult to remove than it is now.

 

[s78wingrider]

Thing it's only good 1 year

 

[studor]

Most bagged cement has an expiry date -- even in super dry conditions it will go off and usually within about three months. Like you I learned my lesson the hard way. Best to just take it out and start over -- JMHO

 

[Western]

Hey Tig There ya go!! Is there any way you could get it out?? If so, might save you many nights laying there thinking...........Drop in shower, you may be fine, but if it degrades over time???

I've used 2 year old bagged sakrete for fence post and had no problems, but it was a fence.

 

[Soundguy]

i've use bags of sackrete that were over a year old. never had an issue with them.. un;less you let them get wet and they turn to paper covered rocks....

 

[Tig]

The only thing worse than screwing up a job would be pretending that I didn't. I've lost confidence in my little stash of masonry cement. Seems that something has gone wrong. There is no plastic liner to the bags, just paper. Glad I did this in two steps so I could let the first part set before I dropped the base on a top layer. Doing it in one step would have hidden the flaw, for now.
To do it over I would lay a few bricks under the base to displace most of the prescribed mortar mound. I'll get at that later this week.
On the bright side looks like I can move the last 6 or so bags to the soon to be filled basement. They were a nuisance in the garage anyway.

 

[Western]

I haven't bought cement in a while that didn't have the plastic liner, that probably shortens the work life considerably.

"On the bright side looks like I can move the last 6 or so bags to the soon to be filled basement. They were a nuisance in the garage anyway. "
See, it has a "silver lining" anyhoo:thumbsup: I wonder if adding a fortifier would increase the strength of the cement?? Probably not worth risking though to save $20 for new sakrete.

 

[dave1949]

Tig, How did your shower pan bedding work out?

 

[Paddy]

Tig,

There are a couple of things here. First, I never understood the point of making a motor mound. It would crush over time. I did it the first time and it sounded like gravel 6 months later. In this home just built, I came from the side and glued in treated wood wedges at several key points. Now it feels real solid and no squeaks or crunching gravel.

The problem I think happened is the plywood base sucks the water out before the chem action can occur. Thus the crumbing. same is true with setting brick and block, if the block is dry it will pull the water out. They always recommend wetting the blocks and keeping it wet. That is hard to do on OSB.

Cement can go bad. We use a portland cement in our factory. We do incoming inspection strength tests before using. It is all time stamped and controlled very closely. But like I said, I don't think that was your problem.

 

[Tig]

Tig, How did your shower pan bedding work out?

I'm still pouting.
I've been staining doors and doing my day job. I'll get back on the shower tomorrow.
Paddy, the mortar was not laid on wood. It was on a tile substrate, kind of like Kerdi but a different brand.
I've tested many points on the mound and a good firm pinch powders it to dust. It sort of explodes like a dry lump of dirt.
If I'm laying thin set on a subfloor I mop it first, to moisten it. That part went well.

 

[dave1949]

I'm still pouting.
I've been staining doors and doing my day job. I'll get back on the shower tomorrow.
Paddy, the mortar was not laid on wood. It was on a tile substrate, kind of like Kerdi but a different brand.
I've tested many points on the mound and a good firm pinch powders it to dust. It sort of explodes like a dry lump of dirt.
If I'm laying thin set on a subfloor I mop it first, to moisten it. That part went well.

Best thing for that shower pan is to go fishing.

Sorry it didn't harden for you.

 

[Tig]

I did check the creek the other night during the hockey game intermission. Pickerel weren't there.
I tore it out tonight before guests arrived. Came out nice. I still have clean the mess. I'll do that in the morning. Then get at installing the base again.

 

[Western]

I tore it out tonight before guests arrived. Came out nice. I still have clean the mess. I'll do that in the morning. Then get at installing the base again.

Smart to follow your instincts and deal with it now. Now you will be able to sleep without the "nightmares"

 

[EddieWalker]

I never save any sacks of concrete, mortar, thinset and grout. They are all cheap enough to buy new when you need them, they take up too much room to store, and you can never trust them to be any good after a few months. I have a gravel driveway and I just dump the sacs on the gravel after a job when I have any left over that my clients don't want. If I can, I prefer to leave them there, but most clients don't want to store it either.

Are you using brick mortar or concrete? Are you building a pan that you will attach tile to or are you just anchoring an existing pan?

Have you ever been to John Bridge Tile Forum, DIY Tile Advice, Tile How-to Information, Tile Your World

Eddie

 

[Dr Dave]

STOP, DONT USE MORTAR ! I did and now my base squeaks, do to shrinkage. I was told, that I should have used non shrinking grout ? Or mortar? I dont remember. Check with an expert first.

Dave

 

[dave1949]

http://www.jacuzzi.com/admin/files/files/4cfd8269-e7b0-4286-9908-7b9743.pdf

"If the subfloor is not level, you must level the entire surface prior to installing the bathtub. The materials used
will insure that the bathtub is supported from the bottom. These materials include: leveling compound, mortar,
plaster or minimal expansion structural foam (having a density of a minimum 5lbs/cubic foot). The bathtub must
remain level in order for it to drain properly and must make contact with the leveling material."

I installed a jet tub years ago that did not come with it's own supports. I had to build a plywood ramp that matched the slope of the tub bottom, then lay a bed of plaster on the ramp. PIA because when setting the tub, you don't want it resting on the lip, just on the bottom in the bedding material. But the lip needs to be close enough to look like it is mated to/resting on the surround. Squish, wiggle, repeat.

 

[Tig]

It's a Maxx Neo Round corner shower base. Good heavy fibreglass over a 1" square tube steel frame.
So this base is well built and well supported overall. The instructions suggest an optional mortar ring to support the drain area. I did once see a very different shower pan break at the drain. The homeowners were very big people, so that wasn't completely surprising. This shower will be in the guest bathroom and some of our friends are rather big people, so I'm going to brace the drain. This showers is over the kitchen. I don't want any flex at the drain.
I have type S mortar mix now and I also have some structural brick. Rather than a mortar mound, I'm going lay the brick around the drain and set the base on a 1" mortar bed on top of the brick.
In my last house, we set a 6" fibre glass tub in mortar as per instructions. 18 years later there were no squeaks.
Thanks for the link Ed. I'll check it out.
In both bathrooms, the kitchen and front entrance I'm very happy with the tile I laid. Shower wall is next. I had to remove the cement board that was installed in the shower. Seems it had been abused and now has the stiffness of box cardboard.
Way back I was a framer in winter, kitchens, renos and windows in summer. Both our fathers are carpenters and we have lots of friends in the trades, so this isn't entirely new to me. This is my second house for myself, although I am taking on way more tasks this time. Once the bathroom is done i have floors, main stairs and trim to go. I'm having fun but my day job does slow me down.

 

[EddieWalker]

I wasn't sure what you where doing until just reading your latest post. What I do is install the tub or shower, test it all out and make sure of all my fittings, and then I mix up a sack or two of concrete and shove it underneath with a board. I just shove as much as I can get under there to create a solid base to support the floor. Of course, you will need access to the underside of the tub or shower, but you need that for the drain connections most of the time anyway.

Eddie

 

[Tig]

Oh it's been in and out of the corner so many times I think I may wear out the stud wall.
There's no access once in place and it's a no glue drain.
Thinking about sand mix now. The one concern that I did have is that once the pan is in place, there is very little opportunity for the moisture in whatever I use, to escape.