If you only shingle over dry felt you would only get about half or a little less work done in a year in the pacific northwest.
Wrinkled felt paper under metal roof.
A good thick organic felt paper like 30 can get some pretty hefty wrinkles if it gets rained on.
What types of underlayment are available for metal roofing and which is the best choice for your design or installation.
Underlayment must also act as a secondary weather barrier in case the roof fails.
Synthetic underlayment is a roofing accessory created by weaving spinning together polypropylene or polyethylene and a polymer to form an all over protective barrier to put between the roofing material and the roof deck.
The first goal of roofing underlayment is to keep the roof deck dry before installation of the metal roofing material.
With metal roofing its also a good idea to put a layer of red rosin paper between the felt or ice water shield and the metal that way it wont potentialy stick to it and cause oil canning and would allow for expansion.
When most people think of roofs they typically think of shingles or metal roofing.
Most codes and good roofing practice would require felt.
Roofing felt also known as tar paper serves as both an extra layer of protection between the shingles and the plywood and as a temporary moisture barrier until all the shingles are in place.
The best underlayment for metal roofs.
But what some may not know is there s another layer of protection directly on top of the roof deck and under the roof covering that performs a critical role in protecting your home from moisture damage.
Just stating facts not saying you can t do it i however don t yes it makes it difficult to make but it is the right thing to do i have also tarped houses like a tent to work through a rainy week another full re sheet i m guessing from house build in.
The traditional and most common material used for roof underlayment on a steep slope metal roof is non perforated asphalt impregnated felt underlayment.
Synthetic underlayment when installed right will lay nice and flat rain or shine until the new roof get s installed.
They can even telegraph through the shingles you lay over top making your roof look uneven.