Problem with vermicrete layer

[John French]

Returning to the project after a long break I noticed that the vermicrete layer was wet - ie saturated. Making a small hole through the stand above the bottom level of the vermicrete layer flowed with water. Therefore I conclude it has taken on water from above or below. My question is how do I deal with this?
I see some have also faced a similar issue and suggested drilling some drainage holes via the base.
Anybody got experience or good ideas.
I recognise firing the oven will dry out the layer slowly - not sure where the water will escape via - but this will surely be inefficient.

[Les]

Re: Problem with vermicrete layer

John,

Is your dome covered of is it just sitting in the elements with exposed vermiculite?

[John French]

Re: Problem with vermicrete layer

It is igloo format and been covered by a tarp - clearly not effectively. I suspect water has entered from above the vermicrete layer, possible via the "corners' ( between the dome and stand ) which are still exposed. I have painted the dome and stand so I suspect drying out it going to be difficult. I had intended to seal the corners which a concrete layer at a slight slope to prevent any water getting in, but clearly that is not a priority right now.
I am leaning towards drilling some hole through the base to allow the release of the water both short and long term. Then hope firing will allow the completion of the drying process.

[Les]

Re: Problem with vermicrete layer

The good news is that if water found it's way in, surely steam will find it's way out. Drilling the holes may be a fix but you need to get it sealed so you don't have to go through the drying process every time you use the oven.

[John French]

Re: Problem with vermicrete layer

I see what you are saying. I thought drilling holes from the bottom of the stand up into the vermicrete layer would enable to gross amount of water to drain without affecting the structure or integrity of the insulation.
In terms of sealing given the holes would be inside the log store cupboard area surely they would only be able to allow for minimal amounts of reabsorption from the atmosphere - as opposed to my artesian basin that I currently have?

[david s]

Re: Problem with vermicrete layer

Yes, drill a few holes up from the bottom, but glue some insect screen over them to prevent intruders. It will take plenty of long slow fires to dry it out.

[Les]

Re: Problem with vermicrete layer

I see what you are saying. I thought drilling holes from the bottom of the stand up into the vermicrete layer would enable to gross amount of water to drain without affecting the structure or integrity of the insulation.
In terms of sealing given the holes would be inside the log store cupboard area surely they would only be able to allow for minimal amounts of reabsorption from the atmosphere - as opposed to my artesian basin that I currently have?

Your approach is sound - just get it sealed from the top. Can you maybe post a picture , the fix maybe obvious to someone. I have a simple dome and zero issues in 5 + years.

[John French]

Re: Problem with vermicrete layer

So I drill up into the vermicrete layer from inside the store ( near the front left hand side ) with my longest drill bit. Just made it into the layer, and the water started to flow. I have collected about half a bucket full so far in about 18 hours. I will monitor the flow rate and may add other drainage holes in other areas depending on progress. I am not sure how effectively the whole vermicrete layer can drain from just one hole, given it is sitting on a level bed. The concrete layer and board that I drilled through we both dry which confirmed that the water is absorbed into the vermicrete layer.

[david s]

Re: Problem with vermicrete layer

I think it is a good idea to engineer at least one hole through the supporting slab to the vermicrete layer before the vermicrete is laid. I have been doing this for all the ovens I build.