Oven support wall cracking

[Unofornaio]

Re: Oven support wall cracking

I'm not really a wood guy so I think of solutions in terms of masonry first but now that you mentioned it I don't see any reason why you could not cut sheets of OSB the dimensions of the side support walls and glue them to the block inside. This would be very easy and a relatively inexpensive way to solidify these walls. Doing this would eliminate the need for the curbing.

I suppose you could do a version of this on the outside of the back wall. Cutting a piece large enough to cover the entire back of the base. This would join the 3 walls (2 side walls (6 or 8") and center wall in-between them) You couldn't do it inside because what we are trying to do here is tie the sides and the back walls together to create a solid U shape.
Now this is assuming the back wall fits "in-between" the 2 side walls like the attachment below. If the back wall is on the "outside" of the sidewalls this will not do any good.
If this back wall is tied into the side walls either with rebar or alternating block you do NOT need to worry about the back.

Your bad news is actually good news this tells me in this (half area) where there are 2 slabs you have greater than 4", combined probably closer to 7" or so which is a good thing.. This also tells me the "new" section of the slab (slab on dirt side) is more than likely the same thickness, it would have to be to make up for the other half (slab on slab side). So it sound like the footing is more than sufficient if this is the case.

As to the 4 x 4, again I'm not a wood guy but I don't think this would be the cause. Even if your getting the heath slab hot to the touch (above say 120 deg) its going to expand in all direction and if anything place a downward load on the 4 x 4. I cannot speak as to the expansion properties of wood itself.

I think what you have is the slab expanded during use (normal) Since these center "wall sections" are tied into the slab via the rebar, also normal,(to be tied in not the sections) when it expanded it pulled a bit on these joints, it doesn't take much to create a crack along a continuous vertical joint. If it has separated thats a different story. Then again if the "new half" of the slab on grade was not compacted properly the back section could be moving slightly. Does the old and new meet below this crack? you say the slab has no cracks did you look at it under the oven where the old and new meet? Or it just could be a crack because of the blocks being stacked like they are. My gut is telling me its from the slab after all the wall has not cracked along the other vertical joints and the rebar is in the block that have the crack.

So at this point it looks like your concerns are sheering up the back wall if it looks like the attachment and keeping an eye on that crack in the hearth slab. There is no point doing anything about the hearth slab right now. Wait and see if it gets worse after a few more firings.

Please keep in mind my concerns with stabilizing the base are strictly for insurance in the event of an earthquake. The oven will probably never move, surely not on its own but if it were to move in an earthquake even a decent tremor it has no side to side strength. Based on what you described retro fitting the base would mean a difference (in a quake) between serious damage/ possible collapse and some minor repair.

[nyknicks]

Re: Oven support wall cracking

The cracks along the mortar joint is about 1'' from the old slab. The cracks do show on both the inside and outside of the walls, but like I said you have to look very closely to be able to see them once the oven cools down. I Looked at the foundation under the oven and I can't see any cracks. Instead of covering the back from the outside I was thinking about using corner braces to tie the back wall to the side wall from the inside. What do you think? I think I'm still going to put some footings on the part of the slab thats on the dirt I think he only went 4" total on that part and about 2'' on the existing patio. This guy cut corners every chance he got. The oven does appear to hold the heat well and is cooking evenly. It was 400f the next day after I fired it up and 200f on the second day after fireing. This is air temperature not the oven surface. I'm no expert but that sounds pretty good to me. If you ever come to the Sacramento area I'll make you some pizza for all your help.

Mario

[Unofornaio]

Re: Oven support wall cracking

You are clearly frustrated with this thing but hang in there.

1" from the old slab?? that means it starts in the new slab and goes up?

The problem I see with the brackets is if the blocks are stacked like you said you really will only be tying in the 2 corner rows of block ya know what I mean? It certainly would not hurt to just do this and would help some. If you are going this route be sure to do as I mentioned with the all-thread and epoxy both available at H.D. Using the liquid nail will not work sorry If you do not have a drill the rental of one and a masonry bit slightly larger than the all-thread is very cheap. You could do the OSB thing on the inside of the back wall and the brackets it wouldn't be quite as strong as the outside but would probably be sufficient.
The epoxy you need to use is made by Simpson, you can get it at Lowe's or HD. You will also need a double barrel caulking gun but you can rent it.

I go up to the Bay Area about twice a month to work next time I might just take a slight detour on the way home and check it out, thanks for the offer.

[Archena]

Re: Oven support wall cracking

Utterly incompetent question alert:

I'm just curious. You mentioned that the proportions were wrong for standard block, but from what I've been able to learn (remember that incompetent part - 'cause I am) mortarless block at least sometimes comes in exact sizes and not the standard, adjusted for the mortar, size (i.e. 16 in. block are really 16 in). I'm just wondering if maybe he used that kind instead? (Why the mortar, I got no clue - I'm just asking.)

If I recall correctly (asking a lot from a tiny brain), the one article I saw where they were straight stacking and not staggering (okay, that part stood out - I know just enough that straight lines up look really scary to me) they were using interlocking (mortarless) block. The blocks were subsequently filled with concrete before the walls were capped (the thing was a house. I would never buy a house like that because you would never, ever convince me that was safe! But, whatta I know?) and rebar was running up through them.

I'm not suggesting anything here - I'm asking only because there's a similarity and I'm curious. The extent of my masonry experience was watching my cousins and my Dad put up our basement walls (very well, actually - my cousins were all in the construction business and Dad could do anything that involved tools). My one contribution was taking a shovel and scraping the mortar splatters off the slab. Dad said I did a good job.

[Unofornaio]

Re: Oven support wall cracking

I'm just curious. You mentioned that the proportions were wrong for standard block, but from what I've been able to learn (remember that incompetent part - 'cause I am) mortar-less block at least sometimes comes in exact sizes and not the standard, adjusted for the mortar, size (i.e. 16 in. block are really 16 in). I'm just wondering if maybe he used that kind instead? (Why the mortar, I got no clue - I'm just asking.)

>>> I see your logic but 5' still doesn't work out for 16" it would be 5'4" I dont know what he did..
If I recall correctly (asking a lot from a tiny brain), the one article I saw where they were straight stacking and not staggering (okay, that part stood out - I know just enough that straight lines up look really scary to me) they were using interlocking (mortar-less) block. The blocks were subsequently filled with concrete before the walls were capped (the thing was a house. I would never buy a house like that because you would never, ever convince me that was safe! But, whatta I know?) and rebar was running up through them.
>>>Vertical steel in CMU (concrete masonry units) is something that is very common here in CA and engineered buildings in other parts of the world. As I mentioned somewhere in this thread if the block were bond beam block (standard block with the top half of the sides and webs missing) even stacked in this manor they could work but it still wouldnt be right. The missing web create a continuous (beam) through each series of blocks and is extremely strong especially with the addition of horizontal steel. Bond beam block are designed to hold steel in the missing web cavity.

I'm not suggesting anything here - I'm asking only because there's a similarity and I'm curious. The extent of my masonry experience was watching my cousins and my Dad put up our basement walls (very well, actually - my cousins were all in the construction business and Dad could do anything that involved tools). My one contribution was taking a shovel and scraping the mortar splatters off the slab. Dad said I did a good job.

>>>that was always the funnest part I remember going with my Dad when I was small, the mortar that fell on the sand he put on the concrete was always in strange stalactites or is it stalagmite (can never remember which it is). Just a light sprinkling of sand protected the slab from stains and the mortar sticking to the floor, when your done you just run a flat shovel on the floor against the wall and it comes off with no problems...Just another one of those invaluable, old-timer tricks. Its funny how we see our fathers differently as we mature, the more I experience in this craft and the older I get the more I see him as a masonry GOD...

[jengineer]

Re: Oven support wall cracking

As the son of an engineering geologist my sage old pa told me.

Mites are mighty and they stand up
Tites are tiety and they hang down.

Parents get smarter as they age!

[Archena]

Re: Oven support wall cracking

I'm just curious. You mentioned that the proportions were wrong for standard block, but from what I've been able to learn (remember that incompetent part - 'cause I am) mortar-less block at least sometimes comes in exact sizes and not the standard, adjusted for the mortar, size (i.e. 16 in. block are really 16 in). I'm just wondering if maybe he used that kind instead? (Why the mortar, I got no clue - I'm just asking.)

>>> I see your logic but 5' still doesn't work out for 16" it would be 5'4" I dont know what he did..

Yeah, I realized it wasn't perfect - just closer.

Unless one of the stacks was 3/4's block - which would make it much, much weirder...

If I recall correctly (asking a lot from a tiny brain), the one article I saw where they were straight stacking and not staggering (okay, that part stood out - I know just enough that straight lines up look really scary to me) they were using interlocking (mortar-less) block. The blocks were subsequently filled with concrete before the walls were capped (the thing was a house. I would never buy a house like that because you would never, ever convince me that was safe! But, whatta I know?) and rebar was running up through them.

>>>Vertical steel in CMU (concrete masonry units) is something that is very common here in CA and engineered buildings in other parts of the world. As I mentioned somewhere in this thread if the block were bond beam block (standard block with the top half of the sides and webs missing) even stacked in this manor they could work but it still wouldnt be right. The missing web create a continuous (beam) through each series of blocks and is extremely strong especially with the addition of horizontal steel. Bond beam block are designed to hold steel in the missing web cavity.

It still sounds scary to me - I like my masonry, drywall and floorboards staggered, please.

I'm not suggesting anything here - I'm asking only because there's a similarity and I'm curious. The extent of my masonry experience was watching my cousins and my Dad put up our basement walls (very well, actually - my cousins were all in the construction business and Dad could do anything that involved tools). My one contribution was taking a shovel and scraping the mortar splatters off the slab. Dad said I did a good job.

>>>that was always the funnest part I remember going with my Dad when I was small, the mortar that fell on the sand he put on the concrete was always in strange stalactites or is it stalagmite (can never remember which it is). Just a light sprinkling of sand protected the slab from stains and the mortar sticking to the floor, when your done you just run a flat shovel on the floor against the wall and it comes off with no problems...Just another one of those invaluable, old-timer tricks. Its funny how we see our fathers differently as we mature, the more I experience in this craft and the older I get the more I see him as a masonry GOD...

We ended up with flat little gobs instead of stalagmites (I learned it as 'Tites go down and mites go up'). My Dad could do almost anything - he'd worked as a chief 'handyman' for a large farming enterprise at one point - they would fly him via helicopter around the state to fix whatever needed fixing. And I know what you mean - I appreciate all he did a lot more now than I did then.

Anyway, thanks a lot!

[Unofornaio]

Re: Oven support wall cracking

>>>Vertical steel in CMU (concrete masonry units) is something that is very common here in CA and engineered buildings in other parts of the world. As I mentioned somewhere in this thread if the block were bond beam block (standard block with the top half of the sides and webs missing) even stacked in this manor they could work but it still wouldn't be right. The missing web create a continuous (beam) through each series of blocks and is extremely strong especially with the addition of horizontal steel. Bond beam block are designed to hold steel in the missing web cavity.

Just to be clear I meant in this case for the oven. The stacking would never pass inspection for a structure unless there was an engineering detail for such in the plans.

[Archena]

Re: Oven support wall cracking

Okay. I'm way too chicken for that either - there was a thread with a lot of pics of a class where they were building an oven. The first thing I noticed was that the stand was utter junk - block are s'posed to at least kinda line up straight and really, the stacks should touch each other. Totally freaked me out until I learned that they only built it for the one workshop - it was torn down afterwards.

Did I mention I'm paranoid where large masonry things that carry huge amounts of weight are concerned?

[edschmidt]

Re: Oven support wall cracking

How about coating the block with quickwall. Its a high strength cement with lots of fiberglass fibers which you spread 1/8" thick and according to the manufacturer gives it as much strength as a mortared joint. It would basically produce a stressed skin where the blocks are responsible for compression and the quickwall is responsible for tension. You would have to put it inside (wood storage area) and outside. once spread it is weather proof and gives a stucco finish, can also be finished with cultured stone,brick,etc. check quickrete.com for more info p.s. I drystacked my block and coated with quickwall and am very happy with the results.

[Unofornaio]

Re: Oven support wall cracking

Hey Ed,
The main issue here is not that the blocks were dry stacked its the way in which the were stacked, directly on top of each other (no stagged joints).

I have not used this product mentioned but have seen others in use. For this instance what we have here is not a traditional block pattern of staggered joints. Even stacked dry, upon kicking they will hold up better than blocks stacked one on top of the other which is what we have here. If the blocks were layed traditional you would have several stagged joints only the thickness of the block sides, what 1" or so? in this example you have a 6 or 8" joint running through the thickness of the entire wall every 16" and at every corner.

Dry stacking the block and grouting them even without steel in this shape for the base is every bit as strong as laying them and grouting them and 100% stronger than laying them and NOT grouting them.

About the coating there are several very cool systems out there that are amazingly strong used mostly for retrofitting old block or brick walls. Most include some sort of synthetic fiber matt adhered to the surface or sandwiched in the layers of coating. Dryvit, a polymer based stucco uses this system and that stuff is STRONG. One of the material yards we go to has a planter covered with it and its been hit several times by bumpers it is still completely intact just pushed in slightly, very impressive to me.

[jwnorris]

Re: Oven support wall cracking

What about a bracing harness system similar to the one shown below?

J W

[Vesuvius]

Re: Oven support wall cracking

I don't know if this problem has been solved. My here's my $0.02 worth.

If the cells are grouted and have steel, I wouldn't worry. If not, take an angle grinder and open up the top cell at the corners of the wall,(just one side of the corner is necessary) and a slot in the top course about 2" wide the length of the walls. Don't worry, nothing will collapse. Take some #5 rebar and slide it horizontally into each slot and then add a bent bar at the corners. Drop a piece of #5 down each opened cell (you can do one in the center if you want also). Push some paper in the cells where there is no steel to save on the mud. Make a loose slurry of grout (HD concrete mix will work fine) and fill the vertical cells and then stiffen the mix with a bit more dry concrete mix. Push the grout into the horizontal saw cut with a trowel.

Push in as much as you can, you'll find a thick pancake batter consistency will work well and pack in high and tight. You can also tapcon form boards as you go to contain the mud but if you get it stiff enough it will stay in place.

All this will take you about 3 - 4 hours and the walls won't move afterward. Don't forget the bent (corner) bars.

[Acoma]

Re: Oven support wall cracking

After reading this novel, I have to say that this gentleman that built the oven definately needs to realize the headache that is occuring. Not to be rude, but how can any person building an oven not properly do the research ahead of time (not you NY). These ovens involve so many steps that need to be thought out before diving in. To line up the walls....? NY, one photo does no justice to all these comments, would you do one from above and one from further out as well? Have you decided the step to take now? Will it be you doing the work to fix this error? You want to enjoy the oven, not worry about it with every use. I think every 2cents added to this thread is almost at a dollar, well, maybe a quarter. I am no mason, but I probably over research everything before getting involved in a project, and ask tons of questions. NY, you can see that you have a top notch support team, led by Captain UNO!

[dalucca2003]

Re: Oven support wall cracking

NYKnicks....I live in Roseville and I used the same gentlemen you used as well, but not for the stand. I used him for assisiting me in the final stages of coating and sealing the dome and could not be happier. He also used a plastic cement/vermiculte mixture and my oven is very efficient at retaining heat. When I am cooking pizza's and the interior temperature is over 900 degrees, my exteranl wall temperature is less than 100 degrees. Most of that is due to the oven being in the sun for a few hours during the day. I was wondering how your heat management is going and did he coat your oven the same way?

As far as the stand goes, I am sure happy I did the work myself. It may have been overkill, but I staggered all the blocks, fill every other core with rebar and finally poured concrete in every core. I then used either 1/2" or larger rebar for the grid and poured a 5" inch structural hearth. Finally, I utilzed Super Isol for underneath the oven and then had the gentlemen in question assist me with the coating of the oven.

Like I said, it may have been overkill, but I took my time and I tease my wife and fiends that if a hurricane or natural disaster occurs, I am heading for cover under my oven. I do not think a nuclear bomb will tear it down.

Let me know if I can be of any assistance as we live very close to one another.