36" build in Tallahassee - AKA Bruce's Folly

[kanoer54]

Re: 36" build in Tallahassee - AKA Bruce's Folly

bruce, i have been following your build with great interest. i am just starting my build in southern illinois and read your posts almost daily. you have raised lots of good questions i would never have thought of asking. i have learned a lot from you and all the others on this forum.

it won't be long and you'll be cooking five-star restaurant meals in your oven non-stop. it will make the food on your trip out west (which i also followed with great jealousy) seem like run of the mill diner food.
best of luck on your flue and entry.
jon

[stonecutter]

Re: 36" build in Tallahassee - AKA Bruce's Folly

I planned to resize, wanting to leave a wider reveal. Was confused for a second, first thought reference to spring line was to outer arch (floor level) then realized you were referring to spring line of inner arch. Thanks again, Bruce

They are one in the same.

Remember, if you enlarge the reveal, you create a higher rise...which will widen your span.

[Bec1208]

Re: 36" build in Tallahassee - AKA Bruce's Folly

The numbers on my diagram are based on a guessimated height of your spring line. You really should measure to get the height...I'm not sure that the span and rise on my drawing will work with what you actually have.

I planned to resize, wanting to leave a wider reveal. Was confused for a second, first thought reference to spring line was to outer arch (floor level) then realized you were referring to spring line of inner arch. Thanks again, Bruce

[stonecutter]

Re: 36" build in Tallahassee - AKA Bruce's Folly

The numbers on my diagram are based on a guessimated height of your spring line. You really should measure to get the height...I'm not sure that the span and rise on my drawing will work with what you actually have.

[Bec1208]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Also, you shouldn't worry about tapering any brick in the arch except maybe the key. Once your form is made you can set it down and do a layout to see how everything works out ..

Thanks again. I will be getting to work on it in a bit. By the way, your diagram cleared things up. I had not quite grasped how to locate point C and was placing it too high. I rotated the image and will attach. I picked up some foam board yesterday, it should be much easier to cut to shape than plywood.

[stonecutter]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Also, you shouldn't worry about tapering any brick in the arch except maybe the key. Once your form is made you can set it down and do a layout to see how everything works out ..

[stonecutter]

Re: 36" build in Tallahassee - AKA Bruce's Folly

I used 3" screws to assemble the form.

[Bec1208]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Bruce, this may be a bit presumptuous, speaking for others but.....

I think it's safe to say that we are rooting for you on this build..not because we feel sorry for your disability, but because of the determination and grit it is taking to get this done in spite of it.

I don't usually get this in depth with layout explanations, but if you need more I'll be happy to continue.

Stonecutter, no I don't think you are being presumptuous. There is no question that I took this build on in part as a personal challenge and recognized I would need advice and support throughout, though largely due to my knowledge and skill level rather than physical limitations. If I receive additional interest, help, and attention due to my physical limitations, I am completely ok with that. I appreciate your help and in the case of the arch, can really use it. I will work out the forms (I picked up some foam board), let me know if there is any special trick to assembling . I am having trouble visualizing the brick tapers and layout. I feel like I am near the finishline, and the entry is the last real stumbling block.

[stonecutter]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Bruce, this may be a bit presumptuous, speaking for others but.....

I think it's safe to say that we are rooting for you on this build..not because we feel sorry for your disability, but because of the determination and grit it is taking to get this done in spite of it.

I don't usually get this in depth with layout explanations, but if you need more I'll be happy to continue.

[stonecutter]

Re: 36" build in Tallahassee - AKA Bruce's Folly

You need to start the outer arch on the same plane as your oven arch. The slab in front of your arch is 6" ( I think you said) below the top of the floor brick.

You can use CMU ( Concrete Masonry Units)* to build up to the correct height without much trouble or added formwork. These will not be seen, as the springer brick will be over it.

Then, the floor inside the vent area, which would be inside of the vent intrados, can be build as usual...out of firebrick.

* You can get CMU brick or 1.25"x8"x16" to make handling easier and so you don't have to cut.

[Bec1208]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Stonecutter, thanks again. I followed you up to here.

I suggest using CMU units mortared directly under your springer brick (first ones in an arch) then you build a firebrick floor for the vent area.

[stonecutter]

Re: 36" build in Tallahassee - AKA Bruce's Folly

I realize a semi shows some mortar on the outside of the brick of the oven opening, but an arch like this has a couple advantages.

1) Easy to build

2) Greater strength, and the shape eliminates the need to buttress the side walls.


You will need to build up the support so your arch springs from the same point as the oven arch. You mentioned 6"...so that is what you must do, otherwise the span must be much,much greater to give you a reveal above your oven opening.

I suggest using CMU units mortared directly under your springer brick (first ones in an arch) then you build a firebrick floor for the vent area.

[stonecutter]

Re: 36" build in Tallahassee - AKA Bruce's Folly

I tried to draw this out, but the arc would curve in about 3" before meeting the outer edge of the side.

The entry's dimensions are: 18 1/2" across hearth floor with 2" of brick to the outside. The height from the floor to the peak of the arch is 12 1/2" with 4" of brick face to the top. The distance from the hearth floor to the top of the stand is 6". The distance left between the front of the oven and the front edge of the stand is 13".

Thanks again. Bruce

O.K. Bruce, I worked something up on paper, to help you see how to strike the lines, and show you how a semi circle arch will work with your oven opening.

Here is the picture..it's the best I can do with limited CPU skill. Just click it to enlarge.....I downsized it to load faster.



First, I used your dimensions above, 18 1/2" Span, 12 1/2" rise. But I didn't know the height of the springing line for your oven arch. I went with 8" after trying it with 6" & 9"....because the radius looked the most like the one in your picture.
*Your existing oven arch is marked in Blue.

I put the span of the vent arch at 24 1/5", which gives you a 3/4" reveal on the apex and then opens up quite a bit on the sides. This is what will happen on any semi-circular arch (if you choose to do this). The numbers I used give you a good reveal, and kept the widening out on the span to a minimum.

I left the layout lines for you ( and anybody else that might want to learn this) to see what I mentioned earlier.

Note the center-line, were I marked the desired rise. In this case 3/4" above your oven arch.

Line "A" starts at the rise point and runs to one side point of the span. This worked out to 18".

Line "B" has a mark at the center... 9". Then a square is placed on "B" holding on the center mark. Trace a line through the center line of the span.

This is were you place your hold point on a trammel or string line.

Starting on either side of the span, trace your arch...it should travel perfectly through the point you marked your rise, and connect to the opposite span point.

This gives you a method for creating perfect semi-circle forms for any size arch.

[cobblerdave]

Re: 36" build in Tallahassee - AKA Bruce's Folly

Gudday
Draw you dimensions on full size on a large piece of paper . Draw a centre line . Rough out one side only it might pay to use something flexible like a piece of hose etc to get the curve. Once you have what you like fold in 1/2 and use a pin to trace through to the outer 1/2 side . Draw that in you should now have something symmetrical . If its not what you want easy to do it again
Regards dave

[Bec1208]

Re: 36" build in Tallahassee - AKA Bruce's Folly

I wanted to share the technique for laying out semi-circle (Roman) arches. Here's an example with arbitrary numbers

First, you need to know your span...lets say 20 inches. Draw a center line at 10" that crosses your span line on both top and bottom, at least 20". Now lets say your rise is 10"...mark that on your center line. You now have three points of a triangle.

Next, measure your distance starting from the center point of your rise, to one sidepoint of your span...right or left. Now, draw a line between these two points, and mark the center.

Using the line you just made, set a square on the line on the center point. The square is now crossing your center line below the high point of your rise. Draw a line along the square until you cross the center line.

This point is where you set the point of your trammel or whatever you are using to trace the arch. Now you have a perfect semi-circular shape for your form ( called centering in masonry).

If you know this already, forget everything I just typed.

I tried to draw this out, but the arc would curve in about 3" before meeting the outer edge of the side.

The entry's dimensions are: 18 1/2" across hearth floor with 2" of brick to the outside. The height from the floor to the peak of the arch is 12 1/2" with 4" of brick face to the top. The distance from the hearth floor to the top of the stand is 6". The distance left between the front of the oven and the front edge of the stand is 13".

Thanks again. Bruce