Roofing terminology is generally the same but I can really only speak to the terms regular used in Vancouver. Most of the terms used can be worked out but if you spend very little time using these words in your vocabulary on a daily basis it can be confusing when they are thrown into a roofing estimate without a real explanation.
Deck is a word used in roofing to describe the base of the roof. Generally a deck is made up of plywood or shiplap. Strapping is another form of deck which is very common with cedar roofs or slate roofs. Strapping are planks of wood, many of various widths and length which are separated vertically about three inches to ten inches between the planks. Duroid and metal cant sit on strapping
Underlay is a term for the vapour barrier used on your roof. The vapour barrier is a paper base or fabric based sheet that lies between a laminate duroid and the deck. The underlay is a protective element to the roof keeping any possible minor leaks out of the attic and allow the water to run down to the eave. If a duroid were to sit directly on the deck in the summer you would find that the deck accually absorbs the ashphalt into the wood and the roof is stuck on permanently. The most important reason for the underlay is to act as a vapour barrier allowing any condensation under the shingle to escape.
Valley is where two sloped roofs meet. There is not much to say about valleys other than it is important that galvanised steel is placed in the valley regardless of your roofing product. Stacks are the little pipes sticking out your roof, gooseneck is an outlet for bathroom fans, it looks like a gooseneck so they are not hard to find. B Vent is the outlet for a kitchen range hoof or a furnace vent. Sometimes this pipe is hidden in an old unused chimney outlet.
Flashing is the metal used on the roof. You may see in your estimate counter flashing which mean metal that raps towards the ground. Under flashing is metal that slides under counter flashing these two terms are mostly used when talking skylight and chimney issues. There is also step flashing which runs upward vertically, normally used where a roof run upwards along a wall. Wall flashing is flashing that runs horizontal where a roof meets a wall.
Gable or rake edge is used to describe the edge of the roof that does not have any gutter. The angled part of the roof and is generally an issue when you are converting your roof from cedar to asphalt when gable flashing is needed to protect the plywood deck. Ridge is the highest point to a roof and runs horizontal, Hips are the angled points of the roof that run off the ridge. Hips are the opposite of valleys and are common with cottage style homes.
Cap or capping is the part of the roof that covers the ridge and hips. Generally the material used in the ridge and hips are the most defined and are extra thick to fight the fact that they are the hardest hit by the elements. Vent is a covered opening allowing the attic to breath. The roof vent sits just below the ridge and normally looks like a box. There is also the ridge vent which runs along the ridge and opens up an air way between each roof rafter. Soffit vent is a vent that sits under the roof along the eave generally right behind the gutter. This is an intake vent and most homes that are older than forty years in Vancouver don’t have one and really should. The soffit vent is an opening with a metal grid which covers the hole.