Proper ventilation keeps your attic close to the outside temperature. In a perfect world your house should have the same amount of intake vents(soffit) as exhaust. To many exhaust vents, some will turn into intakes. Only circulating the air in the top of the attic, not drawing from the soffit. There are many different types of roof vents , all serve the same purpose when installed properly. You cannot mix the type of vents installed in your roof, it's one or the other. If vent types are mixed, shingle manufacturers can and will void the warranty.
Ice and water shield is simply extra protection against ice damming and wind driven rain. It is a self adhering membrane that starts from the eave and stops 1 or 2 ft. Past the interior wall, depending what manufacturer specs call for. (though ice and water shield provides extra protection against ice damming, it does not stop them from occurring).
A gooseneck exhausts your dryer or bathroom fan. I have recently switched to plastic as the metal goosenecks tend to frost more dripping through your bathroom fan cover.
Liberty roofing always replaces wood rot. Framers in the past left plywood overhanging into eavetroughs to prevent water from traveling between your eavetroughs and fascia. This would cause the bottom six or eight inches of your roof deck to rot. Now any good company would use drip edge, which is a flashing installed on the eave that prevents water from going behind your eavetroughs. Installing drip edge eliminates the need to overhang the plywood, cutting it flush to fascia.
Wcb protects you as a homeowner from being sued if a persons is injured while working on your roof. Yes you are liable, always check to see that their account is active!
Sprayed Polyurethane Foam (SPF)
Your building does need to be ventilated in order to maximize indoor air quality (moisture levels and contaminant levels). Most design professionals will advise you to seal the structure as tight as possible and provide the necessary ventilation through the heating and air conditioning system. Many systems employ a "air exchanger" which is designed to pre-condition (either warm or cool) the incoming outside air with the outgoing exhaust air. In this manner, you can build an extremely energy efficient exterior shell using high performance spray polyurethane foam while still providing controlled and energy efficient ventilation.
Spray foam is a two part chemical that expands on the substrate being sprayed filling all cracks and voids. 2lb foam provides air barrier as well as a vapor barrier and nearly double the r-value of conventional insulation.
R-value is the measure of thermal resistance used in the construction industry.
A material that resists diffusion of moisture through wall, ceiling and floor assemblies of buildings. Although most of these materials are only vapor retarders as they have varying degrees of permeability.
When foam is sprayed on a substrate a thin plastic film is produced. This film works as an air seal and stops heat transfer through the movement of air (convection). It's high r-value comes from millions of tiny plastic bubbles filled with air, the foam simply keeps the air from moving.