Leveling top of CMU wall before hollow core planks

[dbattersby20]

I've just checked the top of a CMU wall for level before hollow core concrete planks are placed atop the wall. The wall is about 3/4" out of level and there's not an even plane for the planks to bear on.

Before the planks are placed I'm thinking cement grout should be poured on top of the wall in order to create a level surface. Sikagrout-212 allows it to be poured 1/2" thick so the grout will be 1/2" thick where the wall is highest and 1 1/4" thick where the top of the wall is lowest.

Is there a better, easier solution than this? Perhaps additional, thicker korolath strips could be placed.

 

[KootK]

1) I wouldn't use the korolath strips for that. They're pretty darn hard really.

2) Is this a roof with no topping?

 

[jayrod12]

3/4" out of level over what length? That's a surprising amount to be out of level for the majority of mason's that I've ever dealt with. Most of them are anal about level and plumb.

 

[Greenalleycat]

I would be checking some of the other mortar joints to see where they went wrong
Our workmanship code limits "deviation of bed joint from horizontal" to (5mm over 10m length or less) or (10mm over >10m length)
SO, either way, 3/4" (~19mm) is way outside this tolerance

Sounds like a shit wall, they might need to have another go at it

 

[dbattersby20]

It's 15ft wide x 20 ft. long residential garage with a full walk-out basement. So the hollow core planks are going on the 2nd level, which is at grade on one side. It would probably be 1/2" out of level after about 30 minutes with a grinder taking down a couple high blocks.

Masons finished the last couple courses late in the day and they just got sloppy trying to race against the clock.

Foundation wall is a 10" cmu wall with a bond beam block at the top. after the slabs are installed 2 more courses of 6" block will be installed. one in line with the slab and one above the slab. Hopefully the top course of 6" block can be a little closer to level in preparation for the wood framing.

 

[jayrod12]

So if this is the garage area, or at least if it's floor area, there's going to be a topping slab? I'd likely be making them grind the worst case offending spots, and then have the topping slab a 1/4" thin at the high spot and a 1/4" thick at the low spots.

 

[dbattersby20]

there are hollow core planks going on top of the wall, and a min. 2" topping over the planks with a slope towards the door. I'm not concerned with getting the topping slab level or even getting the planks perfectly level. I'm concerned with the hollow core planks having an even plane to sit on and the potential for a plank to want to teeter when a car is rolled over them. The planks are going to bear on a korolath strip. So to get a nice even top of wall I'm thinking of pouring a minimum 1/2" grout setting bed essentially. The alternative is to cut down the top of the wall with a circular/concrete saw and grinder

 

[phamENG]

Considering you said the issue is sloppy workmanship, I'd be more inclined to make the workman fix their mistake than accept a subpar situation that I'd be responsible for later if it doesn't hold up. But that's easy for me to say sitting here 300 or 400 miles south of you.

 

[jayrod12]

Is it only one wall that's out? If the walls both slope roughly the same amount, then the teetering isn't really a concern in my mind. However if the two bearing walls slope drastically differently, or one is sloped and the other is perfectly level, then I see your concern.

Sika212 or similar would be a reasonable solution. I was just trying to find a "do nothing" way to justify it. Or at least a "do less" solution.

 

[hokie66]

Agree with phamENG. Just have them remove some blockwork and do it right the next time.

 

[dbattersby20]

I would love to make someone redo it but that's not a reality in this case as it's my own house and a different mason started the job but injured himself on another project and I had to have another mason fill in. So if I did try to lay blame on someone they would just point their finger at the other guy.

Jayrod, it's really a corner that is low. 80% of the walls are within 1/4" and the one corner is a little more than 1/2" low. I agree, if there was an even tilt, I would be fine with it because the slabs would sit evenly and not teeter. If there was a high area I would just cut/grind down. But since it's really a "low area" scenario I'm inclined to say filling in would be best. The outside will get a stone veneer and the inside will get finished with insulate and plywood so the grout bed won't be seen again.

 

[dbattersby20]

Hokie, the blocks are grouted solid already and the top course is a bond beam with 2 #5 running through it so it wouldn't be very easy to just reset the top two courses. vertical reinforcement would also be effected if we were to cut off say the top two courses.

Anyone have some insight on how level the top of a foundation needs to be for precast slabs. What are the allowed tolerances?

 

[Greenalleycat]

This is the most relevant thing I could find in NZ codes

 

[Brad805]

Did you talk with your precast supplier? You are not the first with this problem and they will help move the ball forward. If concerned about their suggestion, come on back.

 

[GC_Hopi]