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Oh no - my oven is wet - Forno Bravo Forum: The Wood-Fired Oven Community


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Oh no - my oven is wet

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  • Oh no - my oven is wet

    I just had a mason complete the exterior of the oven. It looks great, fully covered with stone. I can't see any place that water can come in. A few days ago we had a very heavy rain storm here in Virginia. Today I opened the oven door and I can see the back left of the oven is discolored (as if some water was soaked up by the oven back). It's probably about 1/8 - 1/16 of the oven. I can't reach back there but it looks like somehow water found its way to the back of the oven and walked up the back of the oven. The hearth looks fine and most of the oven does.

    I have two problems
    1) I need to figure out where the water is coming in - unless there was just so much rain that it found a way?
    2) What do I do now with the wet oven? Do I need to fully cure it again? Over 7 days?

    I have a casa90 with chimney and cap (I really can't see how the water even if it came from there made it all the way to the back) and my oven is fully covered with stone.


  • #2
    I don't know how old your oven is, but it's not out of the question for there still to be moisture, particularly if you used vermiculite concrete, which absorbs a lot more water than ordinary concrete.

    The first place to look is the door, is your floor tilted in? This might be the culprit. I intentionally slanted my oven floor forward, and the shelf in front of it even more. I figured I wouldn't be making many custard pies or other things where dead level is important in the outdoor oven.

    If it's coming in through the roof, remember that the water doesn't always end up directly below the leak, it can travel on rafters, or other internal structures. The most common problem is most likely the flashing around the chimney. I assume you have a spark arrestor of some sort, that the water just isn't flowing down the flue pipe?
    My geodesic oven project: part 1, part 2


    • #3
      My oven is pretty new - just built this fall. I do have vermiculite. I don't think it's related to the door since the wet spot is on the back of the oven - very far from the door. I think somehow the back floor is getting wet and the moisture is absorbed up the back. My roof is pretty flat - all stone and my chimney was just covered with mortar? (or concrete) and flashing and it was covered during the storm. Is it possible for the water to be so much that the stone or mortar around the stone absorbed the water and it finally reached the oven (past the insulation and more vermiculite)?


      • #4
        Sorry...here are some pictures to better help.

        One picture showing inside my oven and showing the back left wall of the dome as "wet".
        Next picture showing the chimney with cap
        Next picture showing the back of the oven (where the oven dome is wet) fully covered in stone.


        • #5
          I'm a little worried about the edges of the cap stones, I think they should be undercut a little so the water drips off the edge, rather than runs under and down the wall. On the other hand, the mortar should be water resistant enough that it should be tight even if the water is running down the wall.

          I'd adapt a wait-and-see position. In the next heavy rain, take a flashlight and an umbrella and see where the water's going.
          My geodesic oven project: part 1, part 2


          • #6
            Thank you for the advice.

            What should I do about my wet oven (i.e., do I need to cure it again?) The water is still on the back. I would think that the insulation or vermiculite is still wet and will remain that way for a while.


            • #7
              I think David is right with the water movement. Our house has some funny/interesting roof lines, and during big storms we were getting water down an interior wall. It wasn't fun, but I went up on the roof in a big downpour, and found the path the water was taking. It took a little flashing and roofing caulk (later when it was dry) and that stopped it completely.

              You need to figure out what course it is following, and then you can come up with an effective, and good-looking recourse.

              I do recommend that you let the oven dry out for a while, then start another curing process. Sorry about that hassle, but it's the right thing to do.

              Pizza Ovens
              Outdoor Fireplaces


              • #8
                This would probably be a good time for the electric-heater-in-the-oven technique to start drying it before a few fires.


                • #9
                  I think I figured out my problem. I'm sure this is pretty obvious to everyone and their grandmother, but I'm not that talented with building things.

                  I have been looking for a piece of granite to put on the front ledge and still have been looking. Because of this, my front ledge is not slanted the correct way (out and down). It's pretty obvious to me now that the water sits on the ledge and slants inward and the water must have been soaked up by the vermiculite under the hearth and because the oven must be slightly slanted towards the back right the water ended up there and walked up the side of the oven. Make sense? For now I'm going to cover the entire front with a tarp until I get the granite.

                  [first picture of ledge from a side angle]
                  [second picture showing end of hearth and vermiculite beneath]

                  I will probably try and find a space heater since the vermiculte is probably pretty wet below and the oven will stay wet for a while


                  • #10
                    I like the space heater idea. I bought one once that got too hot and kept shutting itself down.

                    Does anyone have a recommendation here? Type or style?
                    Pizza Ovens
                    Outdoor Fireplaces


                    • #11
                      I bought one yesterday from Home Depot. The smallest they had. It has three settings, fan, low, high.

                      I tried it on low within a closed oven and that shut off pretty soon. Last night I had it on fan with the closed oven and I think that was a good prep. This morning I have it on low with the oven door off and the unit's rear right by the opening in the oven (so as not to overheat). After 2 hours it's still running and the wetness is going away

                      I'll probably keep it running all day today. Shut is off at night, then again all day tomorrow. On Wednesday I'll start lighting a newspaper, then....


                      • #12

                        I let the space heater run all day yesterday then shut it off at night. The wet spot definitely dissipated. This morning it looked a little discolored so I assume there is still moisture behind the oven dome. I have the space heater on all day today. In Virginia the nights are getting to freezing so I'm still a bit concerned.

                        My plan is to light up a newspaper tonight, then some kindling tomorrow and so on (unless someone offers advice otherwise).


                        • #13
                          Is there a reason why you are shutting the heater off at night? I would think that if the temperature is the dome is not flaming hot that athe low continuous heat would be better at pushing out the moisture rather than starting and stopping the process.

                          If the heater keeps tripping off due to overheating of the unit then try leaving the door partially closed rather than full open or closed.

                          I would be tempted to McGyver my wifes New Orleans propane oil fryer head into the oven. Get myself a 10-15 gallon tank from a neighbors house on wheels and let it slow cook for 48 hours. Yes the burning of propane will add some moisture to the inside as the process of burning propqane does result in H20. It is a toss up on the electric bill and adding a small amount of vapor that will escape out the flue.


                          • #14
                            Yes, you are right. I will probably leave it on all night tonight. I have the door 75% shut and the heater is still on.

                            Originally posted by jengineer
                            Is there a reason why you are shutting the heater off at night? I would think that if the temperature is the dome is not flaming hot that athe low continuous heat would be better at pushing out the moisture rather than starting and stopping the process.


                            • #15
                              Ran the heater over last night (so 24 hours straight) and then this morning I started the curing process with a small newspaper. The wall got up to 250 degrees and the floor by the newspaper was 100 - 350 degress during the flame.
                              Tomorrow AM will be the newspaper and some kindling.