36" Walthamstow Wood Fired Oven (UK)

[conroyt2000]

hi,
this weekend i made a start on my wood fired oven, poured reinforced slab in the back garden and have materials to get the block walls and suspended slab done over the next couple of weeks.
the design is based upon the FB pompeii oven plans and info from this forum and one in the UK.
I have got hollow blocks which i plan to dry lay and fill cores with concrete and rebar which will then tie into suspended slab.
my first question is do people recommend adding a dpc in addition to the dpm below the foundation slab, if so what level should it go in at - if it goes above first course then there is no continuity of the reinforced cores (i.e. the first course will be hollow and not tied into upper blocks).
once the suspended slab has been poured i was planning to use a insulation board rather than pouring insulation - the garden is small and no access so i have to barrow through the house, along with the improved performance?
any tips/advice is greatly appreciated!

cheers

toby

[Gulf]

Re: 36" Walthamstow Wood Fired Oven (UK)

hi,
this weekend i made a start on my wood fired oven, poured reinforced slab in the back garden and have materials to get the block walls and suspended slab done over the next couple of weeks.
the design is based upon the FB pompeii oven plans and info from this forum and one in the UK.
I have got hollow blocks which i plan to dry lay and fill cores with concrete and rebar which will then tie into suspended slab.
my first question is do people recommend adding a dpc in addition to the dpm below the foundation slab, if so what level should it go in at - if it goes above first course then there is no continuity of the reinforced cores (i.e. the first course will be hollow and not tied into upper blocks).
once the suspended slab has been poured i was planning to use a insulation board rather than pouring insulation - the garden is small and no access so i have to barrow through the house, along with the improved performance?
any tips/advice is greatly appreciated!

cheers

toby

The plastic under your foundation will help protect wood storage area. A second layer (of some type) should be placed on top of your finished concrete hearth just for extra measure. This Moisture barrier should be just below any hearth insulation that you pour or install. This moisture barrier can be more plastic, a painted layer of moisture proof masonry paint, a scrap piece of vinyl floor covering, etc., etc.

Just Sayin'
That translates to just in my opinion .

[Kurtloup]

Re: 36" Walthamstow Wood Fired Oven (UK)

A second layer (of some type) should be placed on top of your finished concrete hearth just for extra measure. This Moisture barrier should be just below any hearth insulation that you pour or install.

Now you tell me.

[Gulf]

Re: 36" Walthamstow Wood Fired Oven (UK)

Now you tell me.

Sorry Kurt,
Let me qualify my statement, from above .
That is something that I wish now that I had of done! Mine is set in a retaining wall. I retrofitted a French drain to help guard against the water wicking. That simple layer above the finished concrete hearth would have helped me avoid all of that. I don't really think it is that necessary for an oven totally above grade. But it can't hurt .

Sorry for the confusion.

[conroyt2000]

Re: 36" Walthamstow Wood Fired Oven (UK)

thanks for yiour responses.
i guess that i will bed this under a levelling screed before i place the insulation board - is there any risk of this melting?
couple more questions if possible!
i wasn't planning on using a preformed lintel/angle iron, rather to either span the front with sufficiently rigid slab or pour a insitu lintel when i am filling the cores - does this sound like a bad idea?
finally, have people installed a threshold to the wood store area to prevent water coming in, if so what is a good solution?

thanks in advance

[conroyt2000]

Re: 36" Walthamstow Wood Fired Oven (UK)

Made some more progress over the weekend. planning on getting formwork built, rebar installed and hearth slab poured this weekend (unless i become a father between then - wife is 39 weeks pregnant). then had plenty of bbqs and practiced by sourdough baking in anticipation of the oven being completed!
spoke to a structural engineer at work last week and he seemed pretty happy that a lintel wasn't necessary provided i kept the rebar as low as possible (with sufficient cover) in the hearth slab.
have sorted the doorway as found an old door lining i can cut down to size.
the site is very crampt which means i have to get a bit inventive with the logistics and double/triple handle things. i imagine that this will become more tricky once i get onto the oven itself.
have been looking at the dome construction and was wondering about brick sizes and cutting. standard sizes here seems to be 230mm x 115mm by either 38mm or 53mm or 65mm. i have a tile saw (cut depth around 38mm) a small angle grinder and a very large heavy duty grinder. i was thinking that i could use the largest size brick in the lower sections and then use a 'thinner' brick in the upper sections where more cuts are needed - this would allow me to cut full bricks as required for the build. has anyone done anything similar and does this create more issues than solves? can't seem to get hold of the brick saws used in a lot of the builds in the states, generally the blades are enclosed creating a max depth of circa 40mm or get a large (expensive) brick saw which is a bit too heavy duty and massive to go in my back garden!

thanks in advance

toby

[boerwarrior]

Re: 36" Walthamstow Wood Fired Oven (UK)

Hi Toby

your base looks solid! I am a few weeks ahead of you, having completed my base and almost ready to start building the oven.

I used a brick arched "lintel" but I think you will be fine with a concrete lintel. Just make sure it is at least 4" thick and use plenty of rebar.

I can't imagine having to carry all material through the house! I guess we're a little spoiled here in the US (I live on 5 acres)

I'll be following your build. Good luck! If there is any way you can get hold of a wet saw with a 10" diamond blade you will be very happy. I can cut a firebrick in half in about 15 seconds

My build is at:
http://www.fornobravo.com/forum/f8/3...nia-19283.html

Neil

[Bookemdanno]

Re: 36" Walthamstow Wood Fired Oven (UK)

Hi Toby! Another Uk Based builder here!

Good luck with your build and check out...

UK Wood-Fired Oven Forum - Home

I used a tile wetsaw for my cuts, going round all four sides and snapping with a bolster. Then place the cut face outermost, where it'll be covered in many other layers.
Didn't use firebricks but it should work. Keep an eye on the Ebay or Freecycle for parts and saws. Occasionally a good-un turns up! If you want to do full tapered cuts, then a tilesaw won't help much. I'd say that different sized bricks would help too. Not sure of quantities though. Kilnlinings offer discounts to UKWFOForum members too.
Good luck!

[conroyt2000]

Re: 36" Walthamstow Wood Fired Oven (UK)

got the suspended slab poured at the weekend.
now need to wait to get the firebricks and insulation (hopefully end of May).
fingers crossed the formwork comes off alright.
planning on buying a cheap abrasive chop saw now (not wet saw) so that i can get the cuts done well for the dome - i've come this far so i want to have a go at minimising the exposed mortar...famous last words.

going to get on with decking and moving the garden sheds around.
think i have settled on cladding the dome with bricks and sealing them, seems to get a good finish and would match local houses if get architectural reclaims

slab is fairly high but am planning to deck the area to bring up the levels, plus can get more kit under the oven!

boerwarrior,
thanks for post, your build looks to be going well! moving all the materials through the house is keeping me fit if nothing else! taking your advice and going for a saw!

bookemdano,
thanks for post too. have been looking at the uk site also; prob going ot use kilnlining as well.

cheers

toby

[conroyt2000]

Re: 36" Walthamstow Wood Fired Oven (UK)

rebar and formwork pics

[cleverdick]

Re: 36" Walthamstow Wood Fired Oven (UK)

Hi Toby,

With hindsight I took a risk by not laying a DPC or even a membrane, but I did use Wickes hardener/frostproofer in the concrete mix for the slab. I also used a plasticiser in the mortar mix (EverBuild Opti Mix) which I hoped would help the mortar cope better with freeze/thaw cycles.

Finally, after a suitable drying and curing time, I gave the whole thing a coat of Wickes Water Seal.

This September it will be 2 years (and many hard Essex frosts later!) and no cracks (so far, anyway)...

[conroyt2000]

Re: 36" Walthamstow Wood Fired Oven (UK)

finally got the materials delivered for the dome, on the hottest day of the year so far....been busy since son was born!
have been mocking up different arrangements, think I will go for a soldier course with a semi-circle door opening and want to try and create a smoking chamber within the chimney area
started cutting through one of the bricks with tile saw, not a quiet job.
have got bigger bricks for the dome than for the floor to minimise the number of joints and went for a 10mm thermal board (high performance one rather than standard one).
planning to put decking down to the height of the door threshold and ideally pergola above

[conroyt2000]

Re: 36" Walthamstow Wood Fired Oven (UK)

finally been able to make some progress, have laid floor, soldier course and got a couple of courses in.
surprising how quickly the joints seem to realign themselves!
doing the cutting with an angle grinder only.
trying to get a course or two done each week.
started with the larger bricks but probably going to go with the smaller bricks for the rest of dome.
my chimney will be slightly larger diameter arch as a lot of the other projects.
not hugely happy with my arch brickwork but it is solid and will be completely hidden once rest is complete, happier with the dome brickwork as starting to get the hang of it.
using a homebrew for the mortar, the special high heat mortar I also bought was a bit of a waste as the joint sizes will always be too great and it won't set properly
just using a quarter circle template rather than IT as seemed a lot easier and hopefully works out fine.
just need to decide upon the enclosure now.....

[conroyt2000]

Re: 36" Walthamstow Wood Fired Oven (UK)

Some further progress.
Any tips would be appreciated with cutting the bricks with an angle grinders, might buy the abrasive cut off saw in link below
Buy alfra 355 abrasive saw online from alan wadkins toolstore
As getting a wet brick saw of sufficient cutting depth is close to ?500+ which is a bit too expensive.
Will clean the bricks with acid once complete.
Going to build a chimney slightly larger than the half dome entrance arch.
The enclosure will be block work to sides then brickwork to the front which will receive render, might put brick slips on the side and enclosure; with pitched roof.
Will then deck the back half of the garden - the oven floor height is too high and I think decking would be better anyway due to the amount of rain over here.
Hoping to finish by mid may.....

[cobblerdave]

Re: 36" Walthamstow Wood Fired Oven (UK)

Gudday
Bricksaws are are recent thing along with refractory cement. Ovens have been built for thousands of years without them. Your joints will be larger but the homebrew will scan the gapes. You'll be cooking faster than you can say dome calculator. Hope I've not offended anyone with that comment.
Regards dave