Chances are your roof structure was designed for a dead load of one layer of shingles plus extra for snow and a safety margin.
Shingles roof layers.
Roofing underlayment is a layer of material usually synthetic or felt that adds extra protection on top of the roof deck and under the shingles.
Synthetic underlayment helps repel moisture and provides protection against water infiltration.
This is water resistant so moisture can pass through and water in a liquid form is blocked.
3 tabs are less expensive but also less durable have lower wind resistance and have a flatter appearance.
The homeowner will have two layers of shingles protecting the roof and the home is less likely to have ice dams he says.
Most building codes allow this but is it a good idea.
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.
Saving on the initial shingle installation doesn t solve the long term cost of adding a second layer of shingles.
Richards also estimates that the homeowner saves at least 1 000 in costs associated with removing and properly disposing of the existing shingles.
Good quality composite shingles can weigh 350 to 450 pounds per square 100 square feet of roofing installed.
Framing includes the roof trusses that sit at the top of your house and support the weight of all the materials used to build your roof.
Here are the pros and cons.
You create them through shingle snapping or buy them directly.
Shingles are the element that most homeowners are familiar with as it is the layer you can see from the outside of your home and it is an important aesthetic aspect.
Pros to overlaying a shingle roof.
That limit pertains to roofs with up to a 4 12 pitch.
You ll need longer nails for this part as you re driving through more layers of shingles.
Bring the ridge edges together with a ridge capping layer.
Most building codes allow up to two layers of organic or fiberglass asphalt shingles.
It will cover all of your roof deck.
Asphalt shingles come in two major types 3 tab and architectural.
Two layers of shingles trap more heat which in turn damages the shingles and shortens the life span of the roof.
Roofing layers from the framing to the shingles so we ll start at the bottom of the deck and work our way up through all the roofing layers until we reach the shingles and sunshine above your roof.
This roofing layer will add even more protection against water perfectly combining with the water shield.