Q. Hey Mark,
We are selling our home, and the buyer’s inspector said our roof has three layers of shingles and said it was a major concern. Now our buyers want us to replace the roof. Why is the number of layers a problem when the roof is not leaking or anything?
A. Hey Judy,
Some municipalities have allowed as many as three layers of roofing materials. Others only allow two. You would need to contact your local building department to see what the roofing codes are in your neighborhood. Regardless of the code requirements, whoever installed that third layer did not follow good roofing practices.
It is very possible that your roof’s internal structure (joists or trusses) was not designed to carry the load of multiple layers of roofing materials. The maximum allowed in most locations is two layers, but I don’t even like to see that. The excess weight may cause the trusses to bow, crack or even break. Saving a few hundred dollars by not tearing the old roof off only shortens the lifespan of the layer on top. Also, some insurance companies will not cover a home with multiple shingle layers.
Anyone replacing the roof on their home should insist on having the current roofing materials removed. This is also an excellent time (and relatively cheap time) to improve the ventilation for the roof, and replace all the flashing materials. Doing so will cost a little bit more, but doing things right in the first place usually pays off in the end.
Mark Nahrgang is the owner of Kingdom Inspection Network Group – St. Louis and is a professional NACHI certified building inspector in the St. Louis metro area. Mark performs home inspections as well as commercial inspections throughout St. Louis and St. Charles County.