Metal Tile Roofs Require Underlayment

That excess moisture ends up as drops of condensation on the roof.

Metal tile roofs require underlayment.

This is a roof membrane underlayment made up of either a rubberized asphalt or butyl based adhesive with a polyethylene carrier sheet. This factor alone can rule out many types of underlayment. However contractors now recognize the benefits of synthetic underlayment for metal roofing particularly when it comes to its tolerance to heat and ultraviolet uv radiation. If your home is built with joists insulation between those joists and sheathing then an underlayment is needed before you put on a metal roof.

The best underlayment for metal roofs. The first goal of roofing underlayment is to keep the roof deck dry before installation of the metal roofing material. An underlayment for use under tiles needs to be rugged enough to support the weight of stacks of tiles. Selecting underlayment for tile roofing the type of primary roof determines the type of underlayment more than any other factor especially in the case of a tile or metal roofing system.

Conventional organic roll roofing felts tend to break down under these conditions of extreme heat. The first on the list would be the ice and water shield. When the metal is eventually replaced roofs without plywood underlayment require the insulation to be replaced or repaired because it is attached to the metal. Traditionally built homes will need an underlayment.

Cheaper felt paper without an astm rating widely sold in home centers is much thinner and should not be used. Underlayment must also act as a secondary weather barrier in case the roof fails. Picture a cloud of moisture floating overhead between the rafters. It has an adhesive backing with a peel and stick feature.

Conversely felt underlayment is appropriate in conjunction with ice dam protection at eaves and other critical transitions in cold climates. In the past in many cases metal or tile roofs have failed because of the underlayment. The industry standard minimum underlayment for a tile roof with a slope of 4 12 or greater is a single layer of astm rated 30 felt paper. Essentially condensation occurs at night when the temperature inside a building is warmer than outside.

On most projects there are two types of underlayments needed. Temperatures under a metal or tile roof can be very high. Although this could be alright in the short term the long term effects are damaging. It is not uncommon for example for original tiles to be re used after the underlayment has been.

Many people don t believe that underlayment is necessary for the metal roof because it s already a sturdy material that comes in large sized sheets and gives sufficient protection to the house. Planning for repairs three decades away may seem imprudent but the cost of plywood today likely is much less than the cost and hassle of re insulating down the road. Architectural metal roofs with felt underlayment are best suited for buildings with proper slope and low moisture loads in dry or arid climates. Warm wet air rises and meets the cold roof and cools.

As it cools it can t hold as much moisture. The simple answer is yes your roof does need an underlayment.