Moisture Protection

[Bill Bogen]

I built my Pompeii 42" oven 4 years ago and have loved every time i have fired her up. This year I noticed a great deal of moisture in the oven and some of the mortar had become dislodged near the transition to the entrance. I live in Seattle and we have had the rainiest winter on record. The oven was uncovered so some moisture was to be expected but this was excessive. The oven is covered with an elastomeric coating that is waterproof but obviously it does not prevent all water intrusion. Now I have replaced the failed mortar, covered it with a tarp and dried it out with an electric heater. My question is, how do you all keep the oven dry in the rainy winter months? Seems like a tarp would hold the moisture in. I really don't want to build a permanent roof over if I can help it. Any suggestions appreciated. Sorry for being so long winded.

[david s]

Have a look for where water may have entered. Common places are around the glue pipe and at the base of the dome where it joins the supporting slab. Water running off the dome will accumulate at this junction and enter into the insulation layers. Given time it will also wet the underfloor insulation. I suggest you fire the oven slowly before sealing up these areas, so moisture can escape where it entered, using long slow fires with bbq briquettes will reduce flame impingement. If you see visible steam from these fires, you are going at it too hard, you risk damage, so back off. Also, if you haven’t already got them, drill a few holes from underneath, through the supporting slab, which will allow the underfloor moisture to vent. We live in the tropics and the oven requires a few slow fires to dry it out after our wet season. A roof is probably the best solution, but more expensive and time consuming than a few fires.

[MarkJerling]

With ours, the biggest point of water ingress seems to be wind-blown rain blown into the oven from the door. Next, some water ingress at slab level.
I've found that if I keep the oven covered with two large tarpaulins during winter, that seems to keep most of the water out.