To meet Section 8, titled Secondary Water Resistance (SWR), your home must have a self adhering polymer modified bitumen roofing underlayment applied directly to the sheathing. This would involve replacing your roof (See Section 2 & 3).

Tape Underlayment                                  Spray Foam SWR Seal

Another, yet less commonly utilized way to meet the SWR Section is by having a foam SWR applied as a secondary means to water intrusion. This involves spraying foam at the point where the truss meets the roof deck. This is not hard to do but takes some time and should be done by a licensed contractor.