Mold first noticed in mid March 2021.  


NE Corner:Mold01

NE Corner after removal of sheetrock:Mold02

North wall near NE corner:Mold03


IR Image of North Wall / NE Corner / part of East Wall (13 March 2021):MoldIR01



CO2 levels continue to be extremely high (1500 to 7000 ppm) and erratic (significant changes hour to hour) which is presumably an indication of continued active mold growth.

2023.05.30 – CO2 levels have continuously declined for the past 24 hrs from 1538 to 420. 

The only other source of such high CO2 that I can think of is organic matter in the soil but the backfill was sand/silt so there should not be any significant organic matter breaking down. CO2 levels elsewhere in the house generally remain below 550-600 ppm even with humans present.

CO2 levels continue to be high and erratic even when humidity in the room is kept below 25% with a dehumidifier.

A dehumidifier keeping the RH below 30% produces anywhere from 0.25 to 1 gallon of water per day. This is with the door closed. Where is this amount of water coming from?



We did a test letting water run over the northern edge of the portico. This did not appear to create a moisture problem in the wine room which would seem to indicate proper waterproofing.  Was this a time issue though that we needed to give it more time?



Builder thinks it’s condensation. This requires moisture though. Where is the moisture coming from? Given the sandy soil, could this amount of moisture come up through the floor (gap between slab & poured concrete walls) as they think?

Interestingly, the months with the lowest avg CO2 levels have been Nov 2022 – Feb 2023. The highest was August.  The avg temp in the room in Aug was 76°f which would have required a massively high dew point to create condensation to feed the mold.



Some photos during the build to give an idea of how it was constructed / insulated / waterproofed. The wine room is under what will be the front portico.

Aerial image facing west:WineMoldBuild 101

WineMoldBuild 103



Lumber cap:WineMoldBuild 105

The drainage mat was removed to ground level and the upper part including the cap is waterproofed:WineMoldBuild 107

Waterproofing is complete. Old drainage mat was reattached with mechanical fasteners but no mastic or similar material. There is a gap between the top of the original drainage mat and the re-applied drainage mat.  Work continues on house. WineMoldBuild 114


Some drainage mat on east face has come off and it appears that the top part on south face is damaged.WineMoldBuild 118