Ice and Water Shield
Roofing Ice and Water shield is a critically component to any new roofing system especially in cold weather climates. Many local building codes require Ice and Water shield and National Building CODE states Ice and water shield must start at the roofs eave edge and extend 2 ft inside heated wall space of a structure.
Ice and Water shield is a peel and stick product that adheres directly to the roof deck. It forms a water-proof barrier where ice most often build up on the eaves edge. It is also commonly applied in the valleys of a house as well as around any roof protrusions including; chimneys, pipe boots, roof vents and skylights. Essentially all the weakest or most prone to leaking areas of a roof should be coated with Ice and Water Shield before installing shingles or any other roofing products.
Is there really a difference in the different brands of Ice and Water Shield? The simple answer is yes but let's go into more detail. Most manufactures offer at least two types of Ice and water shield, standard and Hi Temperature. Hi Temp Ice and Water is used in situations where the roof deck will become very hot such as a metal roof. It is also used in commercial applications where the interior of a building produces a lot of heat such as a large manufacturing facility.
Other Ice and Water shield have come on the market in recent years that promise greater performance and some have other features. GRACE was certainly the innovator in terms of a premium Ice and Water shield. Others have copied what Grace has done creating a product that is especially sticky and performs well in a wide variety of situations. Other products include Granulated Ice and Water shield which is Ice and Water Shield that has granules impregnated on top of it that makes it easier to walk on. There is also fabric faced products available again promising less slippery surface for the roofing installer.
My contractor tells me I need Ice and Water 6ft up or on the entire deck is this true? Maybe. A common reason for putting Ice and Water shield 6ft up in to comply with the "2ft rule". Essentially if you have an overhang more than a foot deep you'll probably ended up putting on 6ft of Ice and Water. All commercially available Ice and Water shield comes in three foot rolls, So if you have a 2ft overhang 1 roll will only get you about a foot inside the heated wall space hence another roll will be required.
Ice and water the entire roof deck? While this is an extremely rare necessity it is sometime called for. Some shingle manufacturers require Ice and water shield on very low sloped decks between 2/12 and 4/12. Also, if you live in a climate such as the UP in Michigan and routinely get over a foot of snow standing on the roof you may want to consider it.