Is it better to remove old shingles in Durham, NC?
With questions like these more details are usually required before a solid answer can be provided. For some homes removing shingles is the clean option while for others they are perfectly ok to leave them on. If you are installing a metal roof over asphalt shingles than it is more than ok to leave them on the roof. However if you are replacing the new roof using asphalt shingles then it is advised to remove the shingles along with the underlayment and damaged plywood (if any).
Metal roofing should ideally be installed on one layer of existing roofing such as shingles, tile or shake as long as the previous roof is in good condition and there are no leaks. If you are looking to install a metal roof it may be a good idea to have us come out and perform an inspection beforehand to determine the health of the current roof before we place a new one on top. If there are any spots on the roof that seem to be weak or compromised they should be repaired before installing a new metal roof and be considered the highest priority. If all of the shingles on the roof appear to be straight and not bowing anywhere the roof is most likely ok and the trusses under the shingles are more than likely sound and strong.
Shingles while individually may not weigh a significant amount, as a whole become very very heavy. Each additional layer you add to the home will only put on more stress to the rafters, framing and plywood. If there are any damages or problems under the old shingles they will only be amplified by the new amount of weight. Good-quality shingles can add 350 to 450 pounds for each "square" (100 sq ft of roof, installed). This excess weight could cause the entire roof to collapse in some cases. One other factor not many think about is your draining systems. The roof you currently have over your head was designed with the gutter and drainage lines. If you increase the overall depth of the roof it makes it slightly higher than the drains. When big storms come you will definitely notice the water spewing all over the place instead of going down into the gutters.
Adding a new layer of shingles on top of a previous one will increase the depth of the roof, affecting sky lights, flashings, dormers and some HVAC equipment. If you are planning on installing a new roof over an old one it is important to take all these things into consideration and plan accordingly. Most of our customers we have helped don’t like the idea of “putting a new band-aid over a worn one” and we understand why. Some states across the country have laws requiring no more than 1 layer of roofing, It is always a good idea to check with the state regulations to see if having more than 1 layer is even a possibility.
One of the biggest concerns with installing new shingles over old ones is not being able to securely fasten the new roof to the deck and rafters. If for some reason a few nails in the new roof are not able to securely enter the wood underneath it will not be a sturdy roof. Sections of partly secured shingles can blow off during wind storms and cause a lot of headache. We are experienced roof contractors and almost always recommend tearing off the old roof to replace it with a new one.
Metal roofing should ideally be installed on one layer of existing roofing such as shingles, tile or shake as long as the previous roof is in good condition and there are no leaks. If you are looking to install a metal roof it may be a good idea to have us come out and perform an inspection beforehand to determine the health of the current roof before we place a new one on top. If there are any spots on the roof that seem to be weak or compromised they should be repaired before installing a new metal roof and be considered the highest priority. If all of the shingles on the roof appear to be straight and not bowing anywhere the roof is most likely ok and the trusses under the shingles are more than likely sound and strong.
Shingles while individually may not weigh a significant amount, as a whole become very very heavy. Each additional layer you add to the home will only put on more stress to the rafters, framing and plywood. If there are any damages or problems under the old shingles they will only be amplified by the new amount of weight. Good-quality shingles can add 350 to 450 pounds for each "square" (100 sq ft of roof, installed). This excess weight could cause the entire roof to collapse in some cases. One other factor not many think about is your draining systems. The roof you currently have over your head was designed with the gutter and drainage lines. If you increase the overall depth of the roof it makes it slightly higher than the drains. When big storms come you will definitely notice the water spewing all over the place instead of going down into the gutters.
Adding a new layer of shingles on top of a previous one will increase the depth of the roof, affecting sky lights, flashings, dormers and some HVAC equipment. If you are planning on installing a new roof over an old one it is important to take all these things into consideration and plan accordingly. Most of our customers we have helped don’t like the idea of “putting a new band-aid over a worn one” and we understand why. Some states across the country have laws requiring no more than 1 layer of roofing, It is always a good idea to check with the state regulations to see if having more than 1 layer is even a possibility.
One of the biggest concerns with installing new shingles over old ones is not being able to securely fasten the new roof to the deck and rafters. If for some reason a few nails in the new roof are not able to securely enter the wood underneath it will not be a sturdy roof. Sections of partly secured shingles can blow off during wind storms and cause a lot of headache. We are experienced roof contractors and almost always recommend tearing off the old roof to replace it with a new one.