How to make wood oven
Complete DIY wood oven building guide
Step-by-step instructions, plans and tips for building a wood oven
Plans
Contact us for fullscale layout plans.
- Plans for different style woodoven and small
- Blast furnaces are available
- Call for price
Plans and pattern:
- Floor layout of cooking chamber and mouth chamber.
- Mouth chamber arch pattern.
- Cooking/mouth opening pattern.
- Relevant measurements for chimney manifold construction.
Instructions on how to build an insulated oven door.
Common mistakes/misconceptions
1. Using an insulating material as a hot face.
2. Buying used bricks that are not suitable for woodovens
- Furnaces or kilns can have ISL or HS bricks as their hot face.
- Ref. “Know your brick”.
3. Placement of the flue/chimney.
Don’t place it inside the dome/cooking chamber.
4. Don’t shut the door when cooking pizzas.
5. Failing to insulate the floor of the oven from the concrete slab that the oven sits on.
6. Using house bricks as a hot face that for some reason don’t retain heat like other house bricks might. Some house bricks are suitable but don’t retain heat as well as refractory bricks.
7. Steel can be used in oven construction. Please call for advice.
Know your brick
Do not buy second hand bricks unless they have 42% alumina content.
Do a heat test
- Heat the brick in an electric oven at 200°C for 4 hours. Use a electronic temp. gauge, take readings of the brick inside oven 2-4 hrs until completely cooled temp.
- Call us for comparison readings.
Know your insulation types:
Insulation range rating: 900-1750°C – general range of temperature that can be blocked.
Different types of refractory insulation:
a) Perlite – 871-1093°C
b) Ceramic Fibre – 1250°C
c) Calcium Silicate – 1250°C
d) Polyball – 1750°C
Bricks
Two types:
1. HS brick – absorbs and holds heat (heat sink)
2. Insulating brick – reflects heat, does not absorb heat
HS brick (won’t crack)
- Weight – 4.3 kg (230x115x75)
- Alumina content min. 35% – 55%
- Are used as the hot face, it absorbs energy from the fire. The alumina content ensures the brick stays hotter longer. When the fire is out the brick stays very hot.
Insulating brick (ISL) (won’t crack)
- Weight: 1 – 2.5 kg.
- Shaped like a brick or tile.
- These bricks don’t absorb energy; they stop energy passing through them. The face gets hot but not their internal. When the fire dies down the brick becomes cold quickly.
- Are used as a heat barrier.
- If you heated this brick in an electric oven then pulled it out and tried to fry an egg on it, the egg would not cook.
Insulating bricks are only used in small furnaces or used to isolate HS Bricks. Heat/Energy will travel through HS bricks and enter whatever its touching or sitting on. So if the HS brick is sitting on an insulation brick, then the movement of the heat is stop.
Concrete: HT castable
Is pulverised HT brick that cement and H₂O is added to make a wet concrete mix which can then be poured into a mold or applied directly to a pattern which is removed once the concrete has set.
Has all the qualities of HS bricks. Absorbs and retains heat. Will not crack if poured as one complete mix
Insulation material (ISL)
Comes in the form of brick, blanket, compressed board or granuals.
- Does not get hot or absorb heat or retain heat.
- Its surface does get hot (not its internal) but quickly cools when heat source is extinguished.
- It reflects heat.
- Do not build your oven wih insulating bricks as the hot face. ISL bricks generally rated to 900°C; above their rated temp heat will begin to pass through it.
- Perlite is a great cheap but bulky insulator.
- Ceramic fibre blanket is most commonly used.
- Calcium silicate board is ridged and great for floor insulation.
The house brick
- Weight – less than 4 kg.
- Are generally extruded and hollow. Pressed reds are a solid brick
- Can a pressed red brick (PRB) be used as the hot face in a woodoven – Yes. Are they as efficient as a HS Brick – No. PRB lose heat quicker, twice as quick as a HSB depending on oven design.
- Italy use PRB for their WFO’s in the old days.
- May crack. PRB are not designed to withstand high temp.
Clay
Is an excellent source of building material. Either dig it up or buy it in a powder form in 20 kg. bags, ie. refractory clay. Mixed with sand and water it is easily used to mold into shape to create a dome or hot face wall.
Won’t cope with temp. above 450°C and won’t retain heat as well as a refractory brick. Walls need to be thicker to help retain TM. Clay walls take longer to dry out before first fire can be lit. Prone to cracking.
Basic theory of a wood oven
Is a cooking chamber that is made up of heat retaining bricks (HS) on the ceiling, walls, and floor. All these surfaces need to be isolated from surrounding external surfaces using special insulation materials.
The idea is to trap the heat from the fire into the surrounding brick surfaces. Its that heat that cooks the food not the heat from the actual burning wood, the flame heat will burn and charr the food hot unlike a blow torch.
If the HS surfaces are not insulated properly then the oven will struggle to reach optimum temp. and will lose any retained heat quicker than normal.
Cooking pizza’s temp. internal – 300°C min. T = 3 mins.
Cooking chicken, meat, and veggies – 100 – 150°C T= 1-3 hours
Summary of how to build a WFO
1. Build the base
Allow 235 mm thickness for each wall
Allow 450 mm for mouth protrusion
2. Insulate top of slab
The floor HS bricks + inner bricks making up
Wall and roof must be insulated from slab. See plans.
3. Lay floor HS bricks / tiles HS
Use mortar to stick HS bricks to layer of insulation.
Ensure HS brick / HS tiles extend under 1st layer of HS Wall bricks
4. Build inner HS brick wall ie. dome or vertical walls for ½ barrel.
5. Build arched ceiling if ½ barrel and or complete inner arch opening into mouth chamber.
6. Complete flue and outer opening to mouth chamber.
7. Light fire to dry brick walls, floor, and ceilings.
8. Build outer insulation walls.
- ie. wrap CFB over bricks (exclude bricks ie. mouth chamber) 2×25 mm layers.
- Wrap a tension chicken wire over CFB.
- Mix perlite 15Lt to 2Lt GP cement to 2Lt of fine sand; add water to make soft mix. Apply over CFB, cover to depth of 50mm.
- Mix and apply 20mm of cement based render to cover perlite.
- Paint with waterproof membrane then tile a grout or apply 2 coats of standard house paint.
The finished outer surface temp range b/co. 40°C – 60°C depending on surrounding ambient temp. eg. Winter temp. 35-40°C , Summer temp. 40-60°C.
Optional: In some oven designs it is easier to build the oven opening first i.e. opening between cooking chamber and chimney chamber.
Glossary / abbreviations
HS (heat sink material)
-
Describes the brick type
-
Allows heat to past through
-
ie. brick, concrete HT or clay that absorb and retain heat
TM (thermal mass)
-
Is the total amount of HS bricks in an oven
-
Units : KG
HT (high temperature) – both HS bricks and insulation bricks can be referred to as HT bricks but each has different properties on absorbs, the other rejects.
HF (hot face) – the surface in contact with the fire source.
ISL – insulating material either brick, blanket, board or grannels. Will stop heat flowing past it; or into it; rejects heat.
Dome – ½ circle shape, similar to an igloo.
Half barrel – similar to a barrel cut down middle with an opening at one end.
Perlite – insulator, mixed with sand and cement to form an insulating layer.
PRB – pressed red brick
Insulator – will not retain heat, rejects, stops passage of heat e.g Dome Wall.
Mortar: HT – cement based product mixed with water that bonds bricks together; has high alumina content to withstand high temp. in WFO.
WO – wood oven
WFO – woodfired oven
Soldier brick – are full bricks that stand upright on end to form first row that the dome 1/2 bricks must be built on. Use soldiers if oven is greater than 700 mm diameter
The half barrel
Advantage: Simpler to build and can be designed for bread baking.
Disadvantage: Difficult to cook multiple pizzas at once.
Aesthetically both shapes look nice.
The half barrel is suitable for bread baking; less so the dome shape.
Furnaces
(To heat and melt metals)
Shapes:
- Cylindrical – is used to melt metals into a special cup (cucible) that sits inside the furnace.
- Rectangular – is used to heat metal hot enough so it can be hammered and shaped. As it cools, it’s reheated and shaping continues.
Furnace gas burners are operated using a high pressure regulator with a thermal couple and flame fail attachment. Please call for pricing.
Chimney and door
Ideally a roof over the oven is best
Two types:
- Stainless steel flue – are easy to increase in height
- Brick chimney – often low in height. Looks nice but often it is not possible to increase their height to stop smoke lingering. Not practical in built up areas. More suitable on open farm land.
Flue hight: a high flue will put the smoke up into faster moving air. At ground level the air movement is minimal. Wind movement oven an area is generally prevailing / constant eg. from the South.
If the smoke lingers then raise height of flue. Brick chimneys are difficult if not impossible to increase their height.
| Flue size | Oven size |
| 100 mm | Not Recommended |
| 150 mm | Up to 800 mm in diameter |
| 200 mm | Over 900 mm in diameter |
Jump up: See diagram 1.
Meats and bread
Unlike pizza, meat and bread must be cooked at lower temperature.
To get the oven at a lower temperature for meat and breads eg. 150-180°C. Don’t accelerate the oven to that temp. Then insert the meat. The result will be tough not tender.
To cook a tender cut of meat the oven must first be fully heated; bricks clean and white hot. Shut the oven down, overnyt or until internal is 150-180°C.
Insert meat in roasting dish or cast iron pan and shut door. 3 hrs approx.
Cover with foil to stop burning.
Tips on cooking pizzas
- Cook using aluminum pizza pans.
- Spray pan with releasing agent (oil in a spray can).
- Roll pizza base with spike to puncture base to stop doubling.
- Seafood is the most difficult to cook due to moisture in ingredients, dry with paper towels prior to making pizza (plating up). Thoroughly drain, squeeze and dry thawed ingredients. Keep toppings to a minimum.
- Choose the right cheese. Some cheeses melt quicker than other cheeses. Using a quick melting cheese may burn a charr before the other toppings have cooked. Slow melting cheeses generally aren’t as tasty but won’t burn as quickly, thus allowing the other toppings time to cook. Use a combination 70% – Hard eg. Cheddar , 30% – Soft eg. Mozzarella
- Add chili flakes 2 mins into cooking.
- Rotate pizza every 15-20 secs, a ¼ turn esp. If close to glowing embers or near wall.
- Don’t cut pizza if sitting in pan.
- If floor is too hot, pizza will cook without removing from pan. Still remove an lay on floor to charr 2-5 secs only.
Temperature for cooking
Time to heat up oven: 45 mins – 2 hrs. depending on oven size a wood type.
As the cooking chamber heats the bricks will lose the dull grey black sooty look and become brilliant in colour as new clean bricks, starting at the top of the ceiling then slowly working its way down to the floor of the oven. At this point allow another 20 mins for the floor to reach wall temp. Ensure walls reach 400°C.
Cooking temp.:
- Walls = 300 – 350°C
- Floor = 320°C
The oven is now ready for pizza cooking.
Insert pizza (on an aluminum circular pizza tray)
Cook pizza on tray 2-5 mins lift pizza edge to check if base is browning. Remove pizza from pan, discard pan and slip pizza on the bare floor. Cook for 10-15 secs depending on floor temp. Constantly check pizza base for browning. Remove when slightly charred.
Rotate when cooking.
If base remains uncooked the oven floor needs to be made hotter.
How the oven works
A wood fire is lit inside a chamber made from either brick, concrete or clay material. (Make sure that this material is heat absorbing). Cooking is achieved with the retained heat. Once the door is sealed the oven will retain heat, slowly cooling over 24-72 hrs depending on the design.
The hot face inside the cooking chamber is what holds the heat. The insulation material behind the hot face stops the heat from escaping through the outer walls of the oven.
Do not seal the door unless oven temp is below 180°C when cooking.
Wood oven supplies:
Since 2003, I first using WO.
| Types of Ovens: | Shape: | Material: |
| a. Wood fired | a. Domed | 1. Brick |
| b. Gas fired | b. 1/2 barrel | 2. Clay |
| c. Heat supply | c. Furnace – square or cylindrical | 3. Concrete |
| 4. Insulation |
Types:
Generally most WO’s are wood fired, used domestically in an outdoors area though some are installed inside the house.
Commercial WO’s may have a gas burner fitted to help temp control. Gas back up system on a domestic WO due to extra cost involved.
Furnaces are all Gas fired either high or low pressure.
Shape:
- There are 2 basic shapes: dome/igloo shape and the half barrel shape
- The dome – is the most common shape.
- Advantage – great for cooking multiple pizzas.
- Disadvantage – time consuming to build.
Diagram 1
The X & Y JUMP UP
Scale 1:10
Diameter Flue – Refer to notes on Flue size to match oven internal
Height difference between x and y approx 130mm
450mm – This measurement is optional it can be greater but not less than 300mm otherwise front brickwork of chimney will be weakened.
H2 must be approx 65% of H1
Example:
- 100% : 65%
- H1= ? : H2 = 950 → H2 x 100/65 = H1 = 1461
(H1) 750 : (H2) = ? → H1 x 65/100 = H2 = 487
Diagram 2
Scale 1:10
Insulation Materials:
- Perlite 50mm
- 50mm Ceramic Fibre Blanket
Wall thickness minimum
115 + 50 + 50 + 20 = 235mm
Note:
- Sit Soldier Brick on top of 300 x 300 x 50 tiles.
- Ensure ceramic fibre blanket, perlite and render touch top of concrete slab.
- Minimum wall thickness approx 235mm.
Diagram 3
Run all four layers of insulation down to concrete slab
- 50mm perlite mix
- 20mm render (point to seal)
- Chicken wire
- 50mm ceramic fibre blanket
Three different styles of insulating 300x300x50 tile from concrete slab. Only one type is required.
- Calcium Silicate
- Insulating Brick
- Perlite cement mix
Diagram 4
Mouth openings & size
Scale 1:10
x = Width of mouth opening: Minimum 380mm maximum is not critical. Having the mouth walls funnel outwards will increase visibility into the oven.
y = Is the depth or length of the mouth, 300mm minimum any less and the flue will be too close to point z and point x the front opening of the mouth, which may cause excessive heat build up & cracking.
