The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Building a small Scott-Style Brick Oven

ClimbHi's picture
ClimbHi

Building a small Scott-Style Brick Oven

I haven't really mastered the photo-posting software on this forum yet, but I got myself a flickr account and loaded a bunch of photos of the construction of my own wood-fired oven. Maybe it can serve as an additional resource for anyone thinking about making their own. Here's the link:


http://www.flickr.com/photos/climbhipa/sets/72157613634415857/


ClimbHi
Pittsburgh, PA

jeb's picture
jeb

Nice!
Now, were you doing the labor, or were the pics of the construction crew?

ClimbHi's picture
ClimbHi

The crew on this consisted of Yours Truly and My Lovely Assistant. (She's the good-lookin' one -- still haven't figured out why she puts up with the likes of me. Maybe it's my baking skills?)


ClimbHi
Pittsburgh, PA

janij's picture
janij

That is so helpful.  I have so many questions.  I guess I will wait for the plans then start asking.  Yours turned out beautiful!!

cleancarpetman's picture
cleancarpetman

ClimbHi--  I am especially interested in images DSCN 2121, 2118, 2117.  I want to transfer that barrel shape to the outside of my oven, as in the photo below.



Is there vermiculite under that cover or are you about to apply it.  What material is that barrel/dome made of?  I am looking for something that will maintain the shape while I cover it in brick.  Thanks.


ccm


 

ClimbHi's picture
ClimbHi

The oven dome is made up of three layers. First is fire brick. (I've read you can use regular brick, but it doesn't hold up as well and is more sensitive to thermal shock.) Next is a layer of regular, heavy duty aluminum foil. This serves as a break between the brick and the next layer so the differing coefficients of expansion do not crack the structure -- kind of an expansion joint. The top layer is a layer of concrete reinforced with steel mesh. The thickness of the concrete is determined by how much thermal mass you want. The more mass, the longer it takes to heat, but the longer it holds its heat. Mine is about 3 or 4" thick at the top, thicker at the sides.


That's the oven, and is really all you need. However, it looks pretty much like a concrete burial vault -- not particularly attractive, IMHO. ;-)   Most elect to cover that with stucco, or, as in my case, with an outer shell. That shell could be any shape you want. The arched masonry shape like that shown in your picture is just one choice. It wouldn't be too hard to build -- here's how I would do it. Generally, you insulate over the oven box with loose vermiculite. In my case, pretty much the whole space between the oven box and the outer shell is filled with it. However, you can add a bit of portland cement to the vermiculite (like is done below the hearth) to make it a setting-type mixture. I'd use that and trowel it over the oven box to the shape of the outer arch, and set the outer brick arch directly on this vermiculite mixture after it had set up, using the vermiculite to hold the brick as you go instead of a temporary wooden arch. The cement/vermiculite mixture sets up kinda like a dry sponge -- something between hard and soft -- enough to keep the bricks in place until the arch is formed (which is self-supporting once it's done), but not so hard as to keep things from moving a bit during heat/cool cycles. (You want the oven to be able to expand/contract independently from the surround or you'll get cracks.)


ClimbHi
Pittsburgh, PA

frankie g's picture
frankie g

CCm....


BEAUTIFUL!!!!  oven!!


I love the stonework.  did you build or have it built?


Frankie G


www.fgpizza.com

cleancarpetman's picture
cleancarpetman

Dear Frank,
     I agree this is a nice oven.  It belongs to someone called Dave.  It is how I want my oven to look though.  Wish I knew who Dave was and where he's from.


ccm


   

mountaindog's picture
mountaindog

Beautiful oven, ClimbHi, and practical location sheltered off of your kitchen! What kind of considerations had to be taken with your local firecode to build inside or adjacent to a house, or is that addressed in the Scott plans? I'd like to build something someday in a sheltered patio area near an above-grade poured concrete basement wall (walk-out basement).


CCM, that looks like a happy guy in your post's pic, who wouldn't be working with a beautiful oven like that!

ClimbHi's picture
ClimbHi

Firecode: It's treated like a fireplace, basically. That means a 2" clearance between the oven structure and any combustable elements. In my case, I "boxed" the oven in with steel framing covered with cement board. That outer box is 2" from the house wall. In addition, there's about 6" of vermiculite insulation between the oven and the outer box.


Also, the flue is tripple-wall stainless, rising 2' above any part of the adjacent structure that's within 10'. By far the most expensive part of the project since I needed a lot of chimney due to the location of the oven.


Another consideration was the need to deal with the hot coals. I constructed a simple "drawer" under the ash dump consisting of a stainless steel pan I picked up at the local restaurant supply store. It rides on angle iron slides welded to the supports for the oven floor. All hot coals go directly into this drawer which can then be immediately removed and dumped in a safe location. (It needs to be dumped or it puts out too much heat back up through the ash dump, cooking the door, if it's on, or worse, cooking the cook! ;-)


ClimbHi
Pittsburgh, PA

newgirlbaker's picture
newgirlbaker

You and your helper did a fantastic job!!  I am jealous. :-)

gavinc's picture
gavinc

Very good job.  A labour of love, obviously.  You will find it very rewarding.

ehanner's picture
ehanner

ClimbHi,
I just browsed through your photo essay of your building project. I'm impressed at how well you thought it through and how nice it looks. The fact you were able to build next to the house makes it all the more functional, year around.


Eric

ClimbHi's picture
ClimbHi

The year-round use feature is the best. Yesterday, My Lovely Assistant pulled some pulled pork out of the freezer for dinner. I made up a baguette, two epi, (our bread supply for this week) and some buns for the pork, despite the fact that it was snowing. Nothin' like a pulled pork sammich on a fresh sourdough roll, some sweetater oven fries, and creme brule for desert!


ClimbHi
Pittsburgh, PA

janij's picture
janij

I got my plans from oven builders today.  What size hearth did you use?  I am having some concrete bids next week.  Our 4" slab is not going to work.  So we will have to cut it and have a 6" slab with footers poured.  I guess we have bad soil ( I knew this from gardening but didn't know it affected pouring concrete.)  I am thinking about going with the 32x38 in one.  I think that will be big enough.

ClimbHi's picture
ClimbHi

Mine is a hybrid, due to space limitations. Mine is wider than it is deep -- the reverse of most ovens. The closest plan to what I ended up with is the small Scott oven. I think the 32"X38" will be fine for home use.


As for the concrete, this is an oven, not a house. Don't let the concrete guys needlessly inflate the budget. You actually don't even need a slab under the oven -- just sufficient support along the perimeters for the walls, i.e., a proper footer. Make sure they understand what's being built and can justify their recommendations. "Bad soil" for concrete is different than "bad soil" for gardening. Concrete wants a stable, well-drained base. If the soil is wet or unstable, they may have to go a bit deeper to reach something that will not move. Also, I forget where you are located, but freeze-thaw may be an important consideration for you as well.


ClimbHi
Pittsburgh, PA

janij's picture
janij

So freeze thaw is not the problem.  Hurrinces maybe.  But we know a guy who does pools as well as stone and things.  I think he is going to let me have the left over concrete from a pool.  Which will save me a lot.  It is the cutting of the 4" slab that I just don't want to do.  Did you put rebar up into the cinder blocks on the base?  I Know the Pizza Guy from above did.  I was just wondering.  The Scott plans don't say it is necessary.  I also founf a construction company down the road with stacks of extra bricks just sitting outside.  I am wondering if they will let me have them.  They have been there a while.


What did you use to cut the bricks on the transition from the dome to the oven opening?  We have a tile saw and a diamond blade.  Will that work?  I have more questions but I guess I will save those for when they come up.


Oh, Did you cook the pork the other weekend in the oven as well as the bread?  That is what I am looking forward to.  Cooking all at once for the week!  Oh and pizza parties!

ClimbHi's picture
ClimbHi

No, I didn't bother with rebar in the blocks. (That's not done all that often even when building houses! Only where there are special load or seismic considerations.) Regarding the foundation, here's my thought: If you can park a car on it, you can put an oven on it, since the oven will weigh less. Are they putting footers under 6" thick concrete driveways in your neighborhood? (I'd be surprised.) I still say if your pad is in good shape and has been stable, it'll probably stay that way with an oven on it. That's gonna have to be between you and your concrete guy though. If you trust him, go with what he says.


As for brick, I used fire brick for the oven, and recycled brick for the outer box. Some say regular brick is fine for inside the oven, but I wanted the peace of mind of fire brick. (This was fun to build, but I sure didn't wanna do it twice in one spot! LOL) This is of particular concern for bread baking, since the steam used can cause some pretty serious thermal shock that common brick may not be able to withstand very well. Recycled brick, or even found stone, would be fine (even preferable) for the exterior.


I just used a small angle grinder with a cheap continuous rim diamond blade, dry, to make all the masonry cuts. You can see it in a couple of the pics. (But don't do this when the nice neighbor lady is hanging out laundry. DAMHIKT!) You can pick one up for around $100 if you don't have one. The blades are only about $10-15 IIRC. A tile saw would work fine for most of the cuts if you have one with the capacity. Mine wouldn't handle a brick thickness (2"+) under the motor. I also cut some bricks lengthwise, on the diagonal, to start the arches. These cuts would have been impossible on a tile saw, but aren't really necessary either.


You also need to notch the blocks in the base to accept the rebar that supports the hearth. You'll need to either do this by hand, like with a drill and chisel, or use a hand-held saw like I did. Tile saw wouldn't work for that. You can also use a circular saw, but the bigger blade would be more expensive, it would be a bit harder to control (not a biggie) and the dust will take a heavy toll on the saw. Still, if I had an old circular saw around, I wouldn't hesitate to use it for this -- IF I didn't wanna buy a new tool. (Yeah, right!) ;-)


We actually had a couple pounds of pork in the freezer left over from the last time we made it, so all we had to do was microwave it and add the Jack Daniel's sauce. Oh, and then not eat for the next three days to lose the weight I gained from pigging out!


ClimbHi
Pittsburgh, PA

janij's picture
janij

Yes I was only going to use them for the exterior.  I am so not taking the chance that the interior of the oven cracks.  So I will go ahead and just buy firebricks.  I don't think they are that expenive anyway.


I will have to ask Kyle is we have if we have an angle grinder.  We have all kinds of tools out there that i don't even know about.  It would not suprise me if we have one.


I have talked to 3 different concrete guys and they are all telling me I need at least 6" of concrete.  I am wondering why they are saying that.  I guess they want the work and keep thinking of the weight of the concrete.  I still have one more guy to talk to.  But the lady with Oven Crafters said the 4" wasn't good enough.


What else have you cooked in yours?  I am thinking of all the things I can cook in succession so as not to waste all that heat.  Oh and where so you get the wood?  We have a fallen oak out back I can cut and lots of other fallen trees around from IKE.  But I was wondering if you had found a good wood supply.


 

PMcCool's picture
PMcCool

I think I'd listen carefully to your concrete guys.  The Houston area soils are typically expansive clays.  In other words, when the soil gets wet, it expands; when it dries out, it shrinks.  Concrete, while very strong, isn't flexible enough to handle the ups and downs of the soil swelling and shrinking underneath it.  Hence, the recommendation for a thicker slab and footers.  The footers, in particular, get you deeper into the soil where moisture content is less variable.  I'd also put some form of reinforcement in it, even if it's just wire mesh.


The other thing to strive for is keeping soil moisture content relatively stable (this is good for the slab under your house, too).  I had an irrigation system installed at my home when we lived there, as much for the good of the foundation as for the good of the grass and flowers.


Paul

janij's picture
janij

This is what I am thinking too.  Esp with the rain we get around here.  It will be reinforced for sure.

ClimbHi's picture
ClimbHi

FWIW, the footer you use will be far more important than the slab as far as movement/support goes. Especially if you are dealing with expansive clays, as another poster suspects.


We pretty much cook anything we can cook in our "regular" oven except things that take fairly precise temp control. Flan comes to mind. Still, with experience, I don't see why you couldn't cook anything.


Wood. So far, I've mostly been using wood I split from neighborhood trees. I do find that the wood works best if it's coked -- I load the next batch into the oven to dry at the end of the bake and leave it there for several days. I also use a lot of hardwood scraps from my shop. I just had to buy my first load of wood -- got a load of cherry that I'll re-split (normal firewood is too big IMHO) and dry a bit more before using. There is a local outfit that kiln dries wood for local restaurants. You could ask places with WF ovens where they get theirs. It's expensive tho' -- over 3X as much as regular firewood. Not worth it for home use where you can coke. Probably necessary for commercial use where this is not possible.


ClimbHi
Pittsburgh, PA

janij's picture
janij

Oh, and did you use thermocouples?  Or do you use a laser thermometer?

ClimbHi's picture
ClimbHi

I mainly use a Fluke infrared gun. http://www.testequipmentdepot.com/fluke/thermometers/62.htm


I rarely need it anymore tho'. Once you've fired a couple of times, you learn to guage pretty well just by time, and looking at the fire and the brick.


ClimbHi
Pittsburgh, PA

janij's picture
janij

We actually have one of those already.  I am sure I will have more questions as we go.  Hope you don't mind. :)

ClimbHi's picture
ClimbHi

Nope. Lord knows I've learned enough from all the other posters on this forum. Happy to be able to contribute in an area I actually know something about!


ClimbHi
Pittsburgh, PA


PS: Not too many people can say they *already have* an IR gun that'll go up to (almost) 1,000°! Now I AM curious! ;-)

janij's picture
janij

We do HVAC and he has one for that.  We also have an infared camera and I can't wait to see what the oven looks like fired after it is built that way.

ClimbHi's picture
ClimbHi

I'll be happy to give you all the oven advice you need if you'll agree to lend me your IR cam next time you're in "da 'Burgh". ;-)


My oven would be pretty unimpressive, color-wise, on a cam. It's better insulated than the house! The snow on its roof doesn't even melt during a firing.


ClimbHi
Pittsburgh, PA

vtelf03's picture
vtelf03

I'm so very jealous - that looks so awesome!


 

Bixmeister's picture
Bixmeister

Here is what I use to bake breads outdoors.  This device can cook over a heat range of +/- 100 degrees F. to over 1000 degrees F. Check forums for the types of things that can be cooked.  The prices are listed as well.


 


Check this link: http://www.kamado.com/

CanuckJim's picture
CanuckJim

ClimbHi and everyone,


Like you, CH, I built an AS design barrel vault, very high mass, 4' x 3' hearth.  Only lately have I gotten an IR gun, which I use mainly for demonstration purposes while teaching.  During the build, I installed four thermocouples: hearth, slab, dome, cladding.  Over time, I've found them to be the most useful, especially because the temps of the mass and inside the brick, not surface temps, tell me how many consecutive bakes I can get and just how fast the hearth and dome temps will drop over time.  I don't use an air temp gauge at all, because I've found it can be misleading, unless I'm cooking a chicken. Just some  thoughts for future builders.


As far as insulation goes, like you I did fill the enclosure with loose vermiculite, but that was eight years ago.  I've installed/built many ovens since then--and learned a lot.  Under the Resurrection thread, you'll find that these days I use a combination of ceramic high heat batting and a castable insulator called Matrilite 18.  Together these are far, far better insulators, inch for inch, than vermiculite/perlite could ever hope to be.  It's more work, sure, and it's more expensive, sure, but how many times will this be done on any one oven?


Although I have the greatest respect for the late Alan Scott, using angle/lintel iron to bridge the gap over the oven mouth is not such a "hot" idea.  These days, I span the gap with a custom cast lintel made from Kastite.  It has the same expansion/contraction properties as firebrick.  Iron does not, and can lead to cracking above it in the dome and in the facade.


I followed AS's recommendation for a vermic/Portland layer below the slab.  However, this is the thermal weak spot in these ovens, because the layer is not that great of an insulator.  After firing the oven for several months (really, really dry), I added a two inch thick layer of high heat insulation board (K-Fac by name, but there are other trade names) under the vermic layer.  This retrofit made a remarkable difference in heat retention, especially because I'm in Ontario and use the oven year round.


Check out Chicago Fire Brick on the web for insulators and castables.


Hope all that helps.


CJ

ClimbHi's picture
ClimbHi

The points you raise were all questions I raised myself when building my oven -- especially the insulation issues. I had considered using high performance insulating blankets as well. However, since my oven is attached to my home, I needed to work with, and get the approval of, the building inspector and following published plans got me the green light instantly. Had I varied from the plans in any significant way, I would have had to get a UL inspection and approval -- at an added cost of over $2K. I chose to follow the plans. ;-)


As for the steel lintel, again, this did cause me to wonder when I was building the oven. I left a bit of room for lenghtwise expansion and hoped that expanision in thickness would be small enough not to cause problems. So far, so good. But . . . .


As for the thermocouples, I elected to skip them for cost savings and go with an IR gun instead. I really missed them at first and found myself wishing I had sprung for them. But as I gain experience with my oven's heat profile, I find I hardly ever even use the IR gun. I do find the air temp guage to be somewhat useful, but only as a guide to help estimate cooking times for such things as roasting veggies, fish (we had killer WFO salmon en croute this weekend) and meats like chicken. I agree that it has little direct use though, since most of the cooking in a masonry oven comes from radiation and not air convection.


That said, I'm filing your post away for use if/when I build another WFO. Especially if it's to be used daily or commercially. Then, the insulation becomes a bigger factor, and durability (such as not cracking from thermal expansion!) becomes critical.


Glad you found our little corner of the Web and hope you continue to share your WFO knowledge and experience with us here.


ClimbHi
Pittsburgh, PA

CanuckJim's picture
CanuckJim

ClimbHi,


There is one trick when you have to use an angle iron lintel: add a thin (1/8") layer of high heat insulation between the bottom of the iron and the surface of the brick.  This will allow some leeway, north-south.  It's also good practice when using a stainless steel, double walled chimney system.  Use the layer between the SS anchor plate and the oven mainifold (usually fire brick or cast refractory), and don't overtighten the tapcons used to attach it; just snug is good.  Having said all that, however, a cast refractory lintel is still preferable.  Alan Scott was a very good guy, but suggesting changes, improvements, modifications to his plans simply did not wash with him.


I still find the thermos useful, especially for teaching purposes and especially for reading mass temps (6" above, 6" below) throughout the seasons.


CJ 

ClimbHi's picture
ClimbHi

"Alan Scott was a very good guy, but suggesting changes, improvements, modifications to his plans simply did not wash with him."


In that case, he probably would've hated that I plan to incorporate a smoke shelf into the design (a la Rumsford fireplace) if I ever build one again. Mine suffers from serious downdraft from the chimney which causes it to smoke out the front unless I close the damper all the way to restrict the chimney. A smoke shelf would eliminate this problem.


Still, my hat's off to Alan Scott since, without him, I probably wouldn't have been able to build my oven -- which I now wonder how I ever lived without! ;-)


ClimbHi
Pittsburgh, PA

CanuckJim's picture
CanuckJim

CH,


I agree entirely.  The sketchiest part of the AS plans is the transition between the vault and the chimney.  You're pretty much on your own.  Having been a professional "stone banger" in my past, I built what was essentially a traditional chimney throat, corbelling the brick inside it, course by course, until I had the right size for the flue tile I used (7" round).  The draw is very good and no smoke out the door.  One provisio for anybody building one of these ovens is not to face the oven mouth into the prevailing wind.


CJ