Possible approach to hearth

[Bec1208]

Hi, I am looking at the feasibility of building an oven largely on my own. I contracted polio in 1954 when I was two years old. I am now affected by post polio syndrome and use crutches for short ambulation and a power wheelchair outside the house. So I am trying to design a stand that is within my physical capability (I can get some help) and within my budget. I am wondering if a stand could be constructed using a shelving unit that is currently on sale at Costco for about $67. It is a five shelf unit (shelves are 18" by 48"). Each shelf is rated to hold a static load of 1,000 lbs and the entire unit for 5,000 lbs. Two units could easily be assembled to form a 54" by 48" surface and and addition shelf could be used to add 18" to the front for the approach. I could use one or more 5/8" cement boards underneath the ceramic board insulation. I am thinking a 32" inch oven would meet my needs and fit on this stand.

I have searched the forum and read much of the content related to brick oven construction. I have not seen where such an approach has been proposed. This makes me think there is some major flaw in my thinking on this. Please give me your best advice for this build. It looks to me like the building of the oven itself can be done in small increments.

If the basic concept looks promising, I also would appreciate suggestions for dealing with the "foundation." I may be able to set this up on an existing slab. If so I could use the metal vertical rails that come with the unit perhaps with some addition support from stacked cinder blocks. If the location has to be on ground, I would need advice on a minimalist approach to footers. I live in Tallahassee, FL so frost and freezing should not be an issue.

Thanks for taking the time to read this post and for any advice you might have for me.

Thanks again, Bruce

[azatty]

Re: Possible approach to hearth

Others have built ovens on metal stands, but you ultimately need some real structure under the hearth. Cement board won't cut it unless you're pouring a reinforced slab over it or you have very little open span. You might be better off dry stacking cinder block to form a solid cube and then build on top of that. It would probably cost about the same, and you probably only need to go up 24 inches if you plan to use it from your chair.

[Laurentius]

Re: Possible approach to hearth

Bruce,

I can't imagine building anything on a $67 dollar shelf from Costco, heavens forbid, anything safe. $67 might get you enough blocks for your support?

[gdest]

Re: Possible approach to hearth

If I understand you correctly the cement board you want to use is just a "fire break" and is fully supported by the costco shelf. This might work but I don't know what the shelf is. But I just want to say is for about the same amount of money, you can build your base with about as much effort it would be to modify the costco shelfs.

Gary

[cobblerdave]

Re: Possible approach to hearth

Gudday
5/8 in compressed cement sheet is pretty strong stuff, I have seenit used as floor on verandas before tiling. Can't remember the joist spacing under it but I don't think it would be any less than 15 in. I recon it should make a strong slab under an insulation layer otherwise the heat will destroy it.
With the shelves your using from what I understand your putting a few together to achieve your size. From the specs it seems strong enough but there not built for outdoor use and would be effected by rust
Perhaps consider going a more conventional method and using someone else to help you even that compressed cement sheet is very heavy stuff.
Hope you project goes well I assure you I lot of the builds here were built by one person so time and determination are just as important as strength and skill

Regards dave

[Bec1208]

Re: Possible approach to hearth

Thanks for all the input. I spent some time today looking at possible sites and rethinking approaches. The best site would be just off our driveway next to the woodpile. Unfortunately that means I would not be able to build on an existing slab.

I know the easiest and likely best solution would be to hire help or buy an assembled or modular oven. However I have an irrational desire to try and build this myself, at least to the degree possible. Though I suspect that in addition to cost savings, this is a motivation of many who choose to DIY their oven.

Anyways, let me throw out some ideas. The main thing I am trying to avoid is having to mix and deal with large volumes of concrete. If there is no DIY alternative I could contract the slab or at least have pre-mix delivered and poured. I could make the stand using dry stacked cinder block and QUIKWALL? Surface Bonding Cement. Still open to suggestions regarding hearth (and foundation). I looked up the specs of durlock board and will add the link below. Looks pretty strong. Again, I appreciate your suggestions. Hoping this turns out to be a feasible project for me.

http://tiny.cc/Durlockspecs

[deejayoh]

Re: Possible approach to hearth

I'd look into having premix delivered. No shame or loss of DIY cred in that! you still need to build forms, your oven dome, your enclosure... Lots to do. If I could have gotten concrete delivered to my site, I would have jumped at it. Unfortunately, I've got 50 stair steps between the street and my oven...

[Bec1208]

Re: Possible approach to hearth

Thanks for all the advice. We decided to have the foundation slab put in by some pros and to have them pour a pad where I can park my wheelchair van that is too tall to get in the garage. Hopefully they can get started this week. I bought a used Felker tilemaster saw off Craig's List. I was in Jacksonville today and filled the back of my van with the ceramic fiber boards and blanket that is not available locally. I also bought three bags of the HW 413 dry mortar mix. Not sure how I will manage the slab, though Azatty's and Laurentius' suggestions to use extra cinderblock seem more practical then my first approach. I find the more I learn the more questions come up. Once I get started I will start a new thread. Agains thanks for the feedback.

[Laurentius]

Re: Possible approach to hearth

Hi Bec,
Happy to see you moving forward with your project. Remember a person with no questions has all the answers.

[WJW]

Re: Possible approach to hearth

Hey Bec...love it.

The DIY thing is pretty universally irrational...but in a good way. Take pics and post them.

I have to concur on using the block instead of metal stand.

Bill

[cobblerdave]

Re: Possible approach to hearth

Gudday
Great to hear your your project on the go!
Remember your the "builder" here and like a house builder you call the shots. Like a house builder you don't have to do it all yourself ..... You have the
" tradies" to do there thing ... The concreters lay the slab to your spec etc.
It's good good to see the whole picture and not get bogged down in the detail
Take you own time and enjoy the journey!!!!

Regards dave

[Bec1208]

Re: Possible approach to hearth

Thanks again for your support and encouragement.

Dave, I looked at your build thread. I didn't see the size of the dome listed (probably missed it) and am guessing it's about a meter. I am leaning toward using the angle iron approach for the inner opening as well. It seems to me that this will simplify making the insulated door. What dimensions did you for the entry?

[cobblerdave]

Re: Possible approach to hearth

Gudday
That's a 42in dome, dome height is 20in, height of entrance 12 &1/2in and 20in wide. My thoughts when building were for a wide opening big enough for anything I could fit in there whole pig cow sheep etc. I also had a deep entry to enable me to have a ambiant fire in the entrance.....I just like the flames who doesn't.
Having a square entrance is a bit old school now but when it came to the chimney the disadvantage is there is no high point on an arch to bring the smoke to the centre and out a steel pipe. So in the end I settled for a chimney running more than width of the entrance running straight up , no constrictions no smoke in the eyes no smoke stains.
I have built an arch in the front of the oven I found it a lot easier than my first attempt and I could explain the process if you want .

Regards dave

[Bec1208]

Re: Possible approach to hearth

Dave, so much for my ability to estimate dimensions. Curious if you would build the inner arch on a redo or are you satisfied with the angle iron? On my side, looks like slab won't be poured until next week at earliest, so have some time to decide. I appreciate your offer to help. Bruce

[cobblerdave]

Re: Possible approach to hearth

Gudday Bruce
Pretty good guess its 1 mtr 50 mm so you were 2 ins out!
Would I rebuild my entrance....no way just to big a job would involve tearing the whole thing down. The angle irons not badly rusted even after 2 yrs now if it does its 2 pieces. Both have the ends Untrapped by bricks or mortar so it's a case of knocked 1out at a time and putting in a new if it comes to that.
If I build another oven I would build and arch like the one I fitted to the front. Straight sides and low arch at the top recon that gives you the most usable shape....and the smokes comes out the middle. I would still build a large brick chimney I like the Idea of no smoke not ending up in your face.
Regards dave