The term “ice and water” describes two different roofing materials; ice-cement sheeting, also known as crack-in or flash-in roofing, and waterproof roofing. Each type of roofing materials provides an array of choices for installation. The following sections will highlight the differences in the types of roofing systems, as well as the benefits associated with each type. Ultimately, choosing the right roofing system can be a challenge, but following these guidelines should help make your decision-making process less daunting.
Ice and water construction involves using rigid waterproofing membranes that are installed above the roofing materials. During re-roofing, the water is drained away, leaving the cement or flexible liner intact. Since this roofing system requires no mixing of materials (such as asphalt) during roofing installation, this option is often preferred by roofers. Although it is the most expensive form of roofing system, it provides the most benefit during an emergency clean-up.
Ice-cement sheeting is formed when compressed air is pumped into the gaps between the metal flashing. Once formed, the sheeting moves up and down with the re-roof. When water is poured onto the sheeting, it expands with the expansion pressure of the water and creates an air pocket between the metal flashing and the ceiling or other roof surface. This air gap provides protection to the roofing materials from freezing damage and keeps the water out of the gaps between the siding and the roofing material.
Step flailing is another alternative to ice-and-water installation. Similar to sheeting, step flailing is created by pumping a special pump into the spaces between the roofing materials. The pump forces the materials upward, creating a step-like appearance. Depending on the roofing materials and complexity, this step flailing method may require more than one round of pumps. The advantage to using this method instead of traditional siding is that the entire roof is not covered, so no roof materials are damaged.
Another method of roofing ice and water removal is to use roofing trims. Trim boards are specially made from PVC plastic and attached to the roof at regular intervals, right up to the rafters. Water enters a hole in the PVC liner and flows into the spaces between the PVC tabs. When the water freezes, it expands, creating an ice dam if the trim board is not installed properly.
Roofing felt also has the advantage of providing insulation against heat loss. To install it, the roof deck must be prepared. This usually requires spraying paint and then scraping off the old roofing materials such as shingles. Afterward, the felt is spread on the roof deck, followed by an application of roof tar, which seals the surface. Then the tar is scraped back, leaving a fresh, clean roof deck surface.
Most people do not prefer step flashing because they feel it takes away from the natural beauty of the roofing materials. In fact, they add to the natural beauty by concealing the caulking around pipes and vent ducts. However, if the existing shingles are removed and the tiles ground down, there will be a space for the step flashing, and this will make the installation easier.
A third way to retrofit step flashing is to add metal flashing to overhang areas where the existing shingles have been removed. It is possible to add metal flashings to areas where re-roofing will be required when the existing roofing material has been damaged by ice and water. If you are installing new roofing material, retrofitting step flashing to overhangs can provide an attractive alternative to the boring regular asphalt roofing. However, you must always check with your local building codes to make sure that the addition of flashing will be permitted.