Recently, we went up to part of the attic that we had never been in 15
years because we are going to sell our house and the home inspection
found out that the builder put the insulation too close to the edge
between the roof and attic floor and covered up the venting, the plywood
under the roof is covered with black mold all over the area. What is
your advise to repair this 1) treat it with fungicide 2) replace the
roof and the plywood and the insulation or any other way we can fix this
problem.

Your quick response will be greatly appreciated because we don't want
the buyers to walk away the sale!!!! Thank you very much

 

Remove the mold with a 10 part water, one part bleach solution, add more bleach if required. If the plywood is not rotten it will not have to be replaced. See if you can restore ventilation to the area. Replace any wet insulation.

 

If you have the black mold, I would probably jump up to the 50/50 solution of bleach and mold. If bleach bothers you, use white vinagar. You can use white vinagar full strength. If your boards are stiff, no need to replace them, but I would open up the vent and get some fresh air in there.