If you don t tear off the old layer you can t examine the decking.
Can you have two layers of shingles on a roof.
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.
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.
Posted july 31 2018 by onpage marie.
Having multiple layers of shingles is going to make your roof hotter because the heat gets trapped between the layers.
Replacing a roof can be very expensive and exhausting at the same time.
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.
In most areas building codes allow for up to two layers of shingles installed on a roof.
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.
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.
As mentioned above homeowners are legally limited to two layer of roof shingles.
If two layers already exist you ll need to remove the old layers before installing a new layer of shingles.
A roof is one of the most vital components of a house.
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.
Any more than that and you d have to tear off the old shingles before installing a new layer.
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.
The standard practice was that you could install a new layer of singles directly over the old layer during a re roof.
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.
Most people would limit this practice to a total of two layers of shingles.