For many years it was acceptable to put even the third layer.
How many layers of roofing are allowed in nyc.
Two layers is the maximum in most areas but some building codes allow only one.
For example towns in climates with heavy hailstorm activity or significant ice dam problems may not allow multiple roofing layers.
That limit pertains to roofs with up to a 4 12 pitch.
Disadvantages to a roof recover.
Richards also estimates that the homeowner saves at least 1 000 in costs associated with removing and properly disposing of the existing shingles.
Most building codes allow up to two layers of organic or fiberglass asphalt shingles.
In the portland area as of 2018 the current code allows up to three layers if the current layer is in good condition.
Homeowners have to also keep in mind that most roofing materials are heavy and can easily weigh over a ton.
How many should there be.
Most building codes allow two layers of organic or fiberglass asphalt shingles on roofs with a 4 12 pitch or less and three layers on steeper roofs.
If the structure can support the added weight a typical 20 square 2 000 square foot reroof will cost at least 1 000 less than a tear off job.
Any amount of short term savings you might see from a layover roof installation is not far outweighed by the longer term peace of mind that comes from knowing that the integrity of the decking has been confirmed.
Although the new york state building code does allow for up to two layers of roof materials.
Why would you want to recover vs tear off.
The homeowner will have two layers of shingles protecting the roof and the home is less likely to have ice dams he says.
Your three layer roof is definitely a potential structural concern and homeowners insurance companies might consider three layers of roof shingles.
On most flat roofs such as epdm tpo or modified it is perfectly acceptable to two layers of roofing.
Generally it is fine to have three layers of shingle but you should check this with your local building permit people and you should make sure that your roof and the rest of the structure have the strength to cope with the extra weight.
Local codes might not allow re roofing.
The soundness of the building you re re roofing is another consideration.
When it s time to replace your roof there are several factors that might lead your roofing professional to recommend adding shingles on top of your existing layers.
However in almost all areas it is not acceptable to install more than two layers of roofing on any commercial building.
