Reasons why you should not add a second layer of shingles it will shorten the lifespan of your roof.
Can you have two layers of shingles on a roof.
The standard practice was that you could install a new layer of singles directly over the old layer during a re roof.
The main case for adding a second layer of shingles is simplicity.
Therefore if you already have two layers you ll need a full tear off.
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.
If you don t tear off the old layer you can t examine the decking.
Most people would limit this practice to a total of two layers of shingles.
The homeowner will have two layers of shingles protecting the roof and the home is less likely to have ice dams he says.
Affects inspection reports.
And roofing guidelines are no exception to the rule.
By not removing the first layer of shingles homeowners would be able to save on labor costs and shorten the time frame of the job.
This will force you to replace your roof earlier than expected.
Having multiple layers of shingles is going to make your roof hotter because the heat gets trapped between the layers which could mean premature aging of the shingles.
There are some advantages to roofing over existing shingles says dale richards owner of richards roofing in troy michigan.
Now for the why.
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.
As mentioned above homeowners are legally limited to two layer of roof shingles.
Another issue is that when you add in the second layer it can add extra weight to your 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 taylor made team.
The second layer of shingles will trap heat which can result in the decomposition of both roof layers.
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 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.
The short answer is yes.
When i started my real estate career i sold homes with three layers of roofing.
This is especially true if you ve overlayed your new shingles on top of warped shingles.