Question about gaps in mortar joints

[Santino]

Hey guys - quick question. I am not experienced or skilled enough to taper all of my bricks, nor do I have the best tools to do the job. I am just cutting each brick in half for each course until I get towards the top. Would it be better to put small pieces of broken firebrick in the mortar joints and use less mortar, or fill the entire gap with mortar? Thank you.

[nissanneill]

Re: Question about gaps in mortar joints

Santino,
there are 2 thoughts to your situation, if using refractory mortar, then as it is expensive, you might place wedges in the wider gaps to reduce the cost but if you use the poor man's mortar, (which I believe is much better, cheaper and not prone to cracking if put on wet bricks). To put wedges in, you will need to cut them which makes more work for you and you may as well then cut your bricks to shape!!!!
You will however need to cut your bricks as you near the top courses as the gaps will increase.

Cheers.

Neill

[Santino]

Re: Question about gaps in mortar joints

Neil, it looks like you were gonna say something after the parenthesis but maybe forgot? Were you gonna say that if I use the poor man's mortar I'd be fine without firebrick shims?

[BarryKeith]

Re: Question about gaps in mortar joints

I did my whole dome with firebrick wedges that I cut trying to make the bricks fit closer together. It worked GREAT and I used far less mortar. I would allow the wedge to hang out of the gap and then snap them off the next day when the mortar had set. Much more functional than using wood shems.

[asudavew]

Re: Question about gaps in mortar joints

I just used mortar. I switched to thirds when I reached closer to the top.

[Santino]

Re: Question about gaps in mortar joints

Hey guys, thanks for all of your replies. I will probably employ both methods throughout, using shims on any real wide gaps and using only mortar when needed. Would you mind answering a few more questions? I posted a couple pics to show what I'm talking about.

1) The first pic is just a dry run of what I wanted to do with my oven arch. The top middle brick is only representative of where my keystone will be so I still have to cut it to fit. Besides that, does it look ok? Should I try to have equal mortar joints throughout or how does that work?

2) Picture 3 shows where I cut the first course brick that meets the arch. I do not have a tile saw so I am using a table saw and I only have a 7" blade so I am having to make 2 passes to cut all the way through. Therefore, it is extremely difficult to get the cut perfect. Will the notches in the cut brick be a problem for strength or will the mortar tie everything together?

3) Picture 4 shows a gap in between the 2nd course of bricks and the arch. Can I just cut a small piece of brick to fit that void or should I just use a full brick and cut it to shape?

Thanks guys for your help. I hope you don't mind all the questions, but I have no construction experience and really no one locally to help me with this so I'm kinda own my own and learning as I go.

[BarryKeith]

Re: Question about gaps in mortar joints

I would think about standing that first row up. I used full brick, but I know many people use half bricks, but stand them up. The gap between the floor and the first (soldier) row will be less standing them up. I would also trim the bricks for the arch so the bottom is smaller than the top, even a little bit will help with the gaps. Going into the arch, get it to fit the best possible. Those were my most difficult cuts. I had the same problem with my 7" saw so I went to harbor freight and got their 10" saw. Don't get discouraged, enjoy the build.

[Santino]

Re: Question about gaps in mortar joints

Barry, I'd like to stand the first row up, but I'm using used bricks. Because of that, I decided to cut all of my bricks in half and use the clean cut side as the interior of my dome to make sure that the cooking area was as clean as possible.

Do you have a picture of what you're describing for the arch brick cuts (bottom is smaller than the top)? I think I understand what you're saying, but just want to make sure. Unfortunately, this is an unemployment boredom project, so money is a little tight to buy the proper saw. But one way or the other, I will get it done right - it just might take a longer (well a lot longer...).

Thanks,
Chris

[nissanneill]

Re: Question about gaps in mortar joints

Santino,

Neil, it looks like you were gonna say something after the parenthesis but maybe forgot? Were you gonna say that if I use the poor man's mortar I'd be fine without firebrick shims?

Sorry to get back so late but that is correct. poor man's mortar is cheap, it fill large gaps cheaply and it is great. No cracking at all in mine so naturally, I'd recommend it.
If however you decided to use refractory cement, then I believe that you need 2 types for thin joints up to 2-3mm and another for the larger ones up to 10mm.Poor man's mortar can be used for all.

Cheers.

Neill

[Santino]

Re: Question about gaps in mortar joints

Neill, thanks for the reply. I'm definitely using the homebrew mortar. I might eventually get my hands on some refractory mortar for free soon, but I already bought my ingredients because I don't want to wait. Just laid my cooking floor yesterday so I'm very excited about pushing through to get this dome completed.

[Santino]

Re: Question about gaps in mortar joints

Ok, going back to what Barry was saying, I tried to taper my arch brick to get it smaller at the bottom, but I realize since I only have a 7" blade, it's not going to work. Can someone tell me if this configuration will work? I've seen plenty of people's houses with an archway that doesn't have a true keystone, but I don't know if that will work for my oven.

Thanks so much.

[Tscarborough]

Re: Question about gaps in mortar joints

If you use the proper mortar, sure, it will work.

[Santino]

Re: Question about gaps in mortar joints

Thanks for the quick reply. I am just finished my 2nd course today so I am going to attempt the dome arch tomorrow. Hopefully it will stay in place!

[nissanneill]

Re: Question about gaps in mortar joints

Santino,

I tried to taper my arch brick to get it smaller at the bottom, but I realize since I only have a 7" blade, it's not going to work.

Mark your bricks accurately and cut as deep as your blade will go from the front. You should then be able to use a brick bolster (wide cold/brick chisel) to break the brick along your saw cut. You could also make a second cut from the back but may nt be necessary.If the back of the cut is rough, it won't be seen and will be filled with your mortar.
Accuracy in marking and cutting will make the difference between an average or professional job so spend that extra effort to get your front arch looking sweet.

Cheers.

Neill

[Santino]

Re: Question about gaps in mortar joints

Neill, here is what it looked like after I tried cutting earlier today. I marked a line from 1/2" in on one end and then took it the corner of the brick on the opposite side. As you can see, since I only drew the line on one side, the cut was not very accurate. The 2nd pic shows how much space is in between cuts where the blade can't reach. Are you suggesting to put a chisel in the cut and break it off and then cut off the part of the brick that is still there?

Cutting the bricks has been a challenging part of the build. The 7" blade was $15. The 10" blade was $70+, which didn't make a lot of sense to me. So it has been very difficult to cut because I end up having to do everything not only twice, but blindly, trying to match up the blade with the pencil line on top.

While I have some people looking at this thread that have been there, done that, how do my first 2 courses look?