Problems with foundation

[texman]

Re: Problems with foundation

Well 3" is a lot. Your choices are to level the slab by excavating it (probably not worth it), level it by topping it with a material made for that (expensive), or cutting the first layer of blocks to level it (normal practice, although usually only within an inch or 2). The maximum you want your initial bedding joint (any bed joint, for that matter) is 3/4".

please look at my oven base. i have used mortar about 1.5" thick to level.
i have not filled the cells yet, so could redo if required. thoughts ?

[ubarch]

Re: Problems with foundation

Update:

DAMN. I dropped like $50 on a diamond masonry blade for a circular saw. I'd been using a composite 4.5" wheel on my angle grinder before, and the difference made it seem like I'd been trying to cut cinder blocks with sarcastic criticism and name-calling.

My first course is level now. Just need to mortar it in place and begin stacking.

Also noticed: The slab is likely tilted because it follows the line of the patio, which is also aggressively tilted. I live on the side of a hill where drainage is important.

[ubarch]

Re: Problems with foundation

Neil2:

I believe it's about 5" thick.

[gdest]

Re: Problems with foundation

I agree with MetalHead thats what I did. I drystacked the cinder blocks filled everyother void (which I believe was overkill) and when I installed the form for the heath, thats what I concentrated on to get level. That being said, being level for your oven, in my opinon is not nearly as important as getting the hearth FLAT. Flat makes a much easier installation for the floor and over all oven. The level can always be compensated for while building whatever sundry attachments you are going to add.

Gary

[Neil2]

Re: Problems with foundation

"I don't know how to judge a slab for how trustworthy it is, though."

Can you dig down at the edge or corner to see how thick it is?. If it is only a couple of inches thick you may have a problem. If it is 4 inches or so you should be OK. The fact that it is 20 plus years old and has no cracks is a very good sign too.

[MetalHead]

Re: Problems with foundation

My brother always told me "You ain't buildin no Piano" . Construction is a world of out of square and not level. That is why finish work profesionals make good money.

If you have to have level, when you get to the top you could build your forms for the pad to correct this. It just depends on where you want to put your work. Build your forms at the top and use a string level to true it up.

But like was just mentioned. Cutting the base course and setting that level will also work.

All that said my slab is on a 1" drop over 30 feet, but runs from back to front. I had this done on purpose so it will drain when I wash it off. Only issue I have is water flows towards the end where everone has to walk on to the slab.... doh !!! I'll have to work on that drainage.

Always some issue to work through

[lwood]

Re: Problems with foundation

What if I tried to level the whole foundation with concrete? It might be cheaper and easier than renting a masonry saw and cutting the cinderblocks.

I would level the first coarse of cinder blocks with mortar and dry stack the rest. The hearth slab is the only thing that needs to be level A coat of stucco and it will all disappear.

[ubarch]

Re: Problems with foundation

What if I tried to level the whole foundation with concrete? It might be cheaper and easier than renting a masonry saw and cutting the cinderblocks.

[fxpose]

Re: Problems with foundation

I've used an old 7 1/4" circular saw with a diamond blade to easily cut around cement blocks. Even your grinder with a diamond blade should do the trick. Those masonry cutoff discs are pretty much useless here.

George

[ubarch]

Re: Problems with foundation

Okay, to make things easier I made myself a water level and snapped a chalk line to illustrate what my tilted foundation looks like. I tried to use an angle grinder to cut along the chalk lines, but I didn't have any success. It's a rather large grinder, but cutting only a shallow score through one block took quite a while and eroded the wheel significantly. Is this really the way it's done? It seems like it'll take forever.

Here's a picture of my water level, and the degree of tilt I have. The red line is level with the corner that's just out of the shot, to the left.

So, do I have to rent a giant masonry saw? Someone earlier suggested that I don't really need to correct a slant like this, and someone else said that it was necessary, and I'm not really clear on whether or not using bricks to raise the low cinder blocks is a good idea or not.

Any help appreciated.

[ubarch]

Re: Problems with foundation

It looks to have been around since perhaps the 1980s or 1990s, and isn't cracked. It's a bit rough and has a few names scratched into it from when it was wet. My guess is that it's a home job from one of the older owners.

I don't know how to judge a slab for how trustworthy it is, though.

[fxpose]

Re: Problems with foundation

And using a bed of mortar between the foundation slab and the first course will make leveling easier. Once the first course is nice and level you can dry stack the rest.

Aside from that, do your trust the existing slab for use as your foundation?

George

[ubarch]

Re: Problems with foundation

I see what you're getting at. I'll try to do it with an angle grinder and a masonry cutting wheel.

[fxpose]

Re: Problems with foundation

ubarch......take a look at this member's foundation slab and how he leveled his first course of cmu's:

http://www.fornobravo.com/forum/8/realjaydubs-minneapolis-build-42-a-13436-2.html#post93935

[Tscarborough]

Re: Problems with foundation

The term "shimming" is bad, but cutting the cmu or brick to fit the slope is not a problem and is done as a matter of course in normal construction. So long as you can get the top of the first course level-ish, no worries.