Posted july 31 2018 by onpage marie.
Can you have two layers of shingles on a roof.
If you don t tear off the old layer you can t examine the decking.
In most areas building codes allow for up to two layers of shingles installed on a roof.
But contractors who spoke with angie s list say best practices call for stripping the roof down to the wood deck to inspect it before installing a new roof.
Additionally if your roof is severely damaged it likely won t be able to support the weight of a reroof and will need to be torn off.
If you have done some serious research on roofing then you have probably heard about adding a second layer of shingles on top of the old ones.
The average 30 square roof uses 90 bundles of shingles and a bundle of asphalt roofing shingles weighs about 100 pounds which means you re putting roughly 9 000 additional pounds of weight on your roof.
If two layers already exist you ll need to remove the old layers before installing a new layer of shingles.
Therefore if you already have two layers you ll need a full tear off.
Now you just have to decide whether to remove the existing roof shingles or recover the roof.
Pros and cons of adding a second layer of shingles.
Any more than two layers of shingles can be too much for the roof to handle even if the local building codes don t outlaw it.
When it s time to replace the roof again and you have no choice but to start anew two layers is the maximum allowed in most areas you ll have to pay extra for the two layer tearoff and disposal.
Though both these points are valid you will end up spending the same amount of money or more later to have two layers of shingles removed.
Eliminating the tearoff can easily save 1 000 or more on a new roof but you re really just delaying the cost.
For a second layer to be as good as a roof tear off you would have to have sound decking no leaks and a roof with no sidewalls where flashing is needed in order to tie the tiles in to the exterior walls.
As mentioned above homeowners are legally limited to two layer of roof shingles.
Any more than that and you d have to tear off the old shingles before installing a new layer.
Most people would limit this practice to a total of two layers of shingles.
Replacing a roof can be very expensive and exhausting at the same time.
Since the second layer makes removal more difficult you will find roofers have to work longer to get the surface ready for a fresh layer of shingles creating higher labor costs the second time around.
Most cities and towns allow a maximum of two layers of shingles says chad muth president of muth company roofing in westerville ohio.
