We have an older home built around 1930. It is a cottage type, bungalow home. We want to install knotty pine tongue and groove boards (not the wainscotting type) for a ceiling. However, the joists are not 2 x 6's, they are 2 x 4's. We need your suggestions. HELP!

1. We have a wood stove installed through a fireplace
2. The dry walls have been removed and we installed tongue and groove.
3. The electrician installed wiring, and hung the boxes without the lights of course.
4. We have slanted ceilings.
5. We are planning to insulate the ceiling. t
6. The spacing between the so called studs (joists) are 16" in some and 24" in others.
7. The outside of house is redwood.
Hope this info helps....