I have a 14 year old double wide mobile home and the roof is leaking in several places. I have been told it all needs to be stripped off and new shingles put on. I have also been told that a second layer of shingles can be layer over the existing. Can a second layer be put on top of the existing?
I'm very familiar with mobile home design.
Multiple layers of composition shingles have been done successfully for over a century, however the extra weight is not to ignored and especially on a mobile home.
The simple answer is; Check with your local building department.
Also, comp shingles need to have a minimum pitch to function properly. Anything below a 4ft in 12ft pitch and your asking for trouble. Most mobile homes have a 3/12 pitch or less.
I would bet your problem is actually the wrong type of roofing material. This time, I would go with a low slope material like "Torch-on roll roofing".
Orange County Roofing, With Pride