We have a problem with a subfloor in a bathroom. The builder tiled the bathroom, but did NOT use backerboard, and we had a leaky toilet which made the subfloor moldy and it bulked up.
The toilet is next to the bathtub. The damage is till close of the bathtub. The toilet is located between 2 I joists, and there is a third I joist under the tub. We need to remove a part of floor and cut between the toilet and tub... But we don't want to lift the tub out really... Does sistering give enough support for the piece of flooring?