Before using Thoroseal, if there is a joint or crack on the inside of the curing room where the leakage may be occuring/worst, open up the joint. A dovetail shape is suggested and then pack in hydraulic cement. This can be done if the concrete is moist.
After the joint is packed, apply the Thoroseal to the inside of the kiln. Again this can be done when the wall is moist and instruction do suggest wetting the wall first. You may use a latex additive to increase the bond. Thoroseal is a dry mixture of materials that must be mixed properly. If I recall correctly, the instructions say to mix and allow to set for a period and then add water if necessary and remix. The consistancy is like pancake batter and it can be messy to apply. Having the wall pre-wetted makes the application easier.
Most other materials will require the wall to be dry, which will difficult if you have a room full of sampleswaiting to be tested.
