2025 Pompeii Oven Build Log

[Gulf]

Some have used products that are normally used for underground basements. One, over here, goes by the brand name "Redgard". Similar products may be available to you. However, I still like some type of open roof over an oven. That seems to be a great way to save the looks of an igloo and still protect it from the elements.

[david s]

I use a product called “flexible pointing”, ( it may be called something else in different countries), which was developed to cover the mortar on tiled roof ridge caps. Because a tiled roof, just like an oven is subjected to continual expansion and contraction, the flexible pointing uses an extremely flexible acrylic and to achieve high build thickness, fine sand is also contained in the mix. Because it will also receive a lot of sun, there is plenty of UV protection also added to the product. It is fully waterproof, UV resistant and highly flexible so ticks all the boxes as a suitable product for WFOs. An old roofer told me that prior to its development in the 70’s roofers often had to re-mortar ridge caps to prevent roof leaks, but since it’s become industry standard, they never have to do those repairs.
As it is designed to be troweled on, for easier application I water it down 20% so it can be painted on in about 3 layers to achieve a thickness of around 1.5mm.

[yoboseyo]

I use a product called “flexible pointing”, ( it may be called something else in different countries), which was developed to cover the mortar on tiled roof ridge caps. Because a tiled roof, just like an oven is subjected to continual expansion and contraction, the flexible pointing uses an extremely flexible acrylic and to achieve high build thickness, fine sand is also contained in the mix. Because it will also receive a lot of sun, there is plenty of UV protection also added to the product. It is fully waterproof, UV resistant and highly flexible so ticks all the boxes as a suitable product for WFOs. An old roofer told me that prior to its development in the 70’s roofers often had to re-mortar ridge caps to prevent roof leaks, but since it’s become industry standard, they never have to do those repairs.
As it is designed to be troweled on, for easier application I water it down 20% so it can be painted on in about 3 layers to achieve a thickness of around 1.5mm.

would you use this as a primer layer on the dome? or over or under the primer - I'm tiling over it so it has to adhere?

what are your thoughts on waterproofing vs not water proofing? Are the water resistant layers enough and water proofing is a nice to have, or a must?

I'm in Australia (Canberra)

[david s]

Thanks for providing your location because much can depend on climate. Traditionally I talian ovens are out in the open but do not have waterproof coatings. A roof over the oven is probably the best solution, but is an expensive one. Even a roof will not prevent moisture entering via humidity (not really a problem in Canberra). We live in tropical Nth Queensland and during our wet season the oven will pick up moisture which needs to be purged by a long slow low fire the day before attempting a pizza firing. This is rarely a problem because it is unpleasant being outside in those months, too hot too humid and too wet, so inside with the aircon is the preference. Any totally waterproof coating also has the disadvantage of holding moisture in, but my preference, in our climate is to waterproof the outer dome shell with weep hole vents located both under the floor as well as under the insulation layers. Any steam pressure build up in the insulation forces moisture down and out.
I do CFB layers and a 35mm 10:1 vermicrete layer (weak enough to be as good an insulator as blanket and just strong enough to act as a suitable substrate to render against). The oven needs to be slowly purged of water at this stage before proceeding.
My render is a 12-15 mm cement render ( enriched with lime to provide elasticity) for the outer shell, over which, after covering with clingwrap for a week to enhance strength by damp curing, I paint 3 coats of the diluted flexible pointing.
I hope this makes sense. It’s what I’ve arrived at after many years of oven building, but is certainly not the only solution. Oven building is like boat design, there are many different variables depending on application.

[yoboseyo]

My render is a 12-15 mm cement render ( enriched with lime to provide elasticity) for the outer shell, over which, after covering with clingwrap for a week to enhance strength by damp curing, I paint 3 coats of the diluted flexible pointing.

Thanks for the detailed description.

Since im going to be tiling outside of it, is pointing a suitable surface for primer and adhesive?

Over a membrane like Davco k10? Thats the one i was originally considering, but it's designed to go over the primer, and under the adhesive.

Edit: I have both weep holes and a dome vent as per your recommendation

[The foxdale phantom]

david s , can I ask what medium you use to dilute your flexible pointing ? Assuming water?