A friend is getting their roof resurfaced with new shingles and they are going to replace their aging skylights at the same time so that they don’t fail in a few years and cause a problem. They are wondering what shape skylight they should get and are hoping that the flat flush mount glass skylights will fit their needs. Their home has a rather flat roof and at parts it is only 12/3 or about 14degrees pitch. They also live in an area that gets snow and their contractor is telling them they should stick with a dome style because that will be better in the snow.
The first thing you should do if you are considering getting skylights is to drive your neighborhood or surrounding neighborhoods and see what types are being used by your neighbors. If you know someone down the road that has a similar pitch roof and a model you like then ask them or maybe you will get lucky and they will be out in their yard and you can explain your situation. Most people that have unique features in their home are happy to talk with interested people.
The reason that the contractor is pointing our friend to dome skylights is that they are specifically for the situation he is in. In wet and snow conditions Dome Skylights if given the same flashing and build quality will out perform a flat flush mount glass window. This might be a pretty straight forward situation for our friend but what about your home?
Fixed Vs Vented Skylights
Vented skylights come with a few options. The most basic is a hand crank option to open and close the window. Sometimes the cranks are fitted so the rod will extend to a point where it is very easy to attach a crank and perform the opening and closing but in tall or vaulted ceilings you are probably better to step up to a motorized unit.
Motorized sunroofs have their own problems. If lightning was to strike and turn your power out during a storm and your skylights were open then you are going to have to depend on a manual override crank if available on your unit and if you can find the crank to close it. Other that that problem which could be pretty dramatic the other option you might have is solar operated units and ones with auto sensing for rain.
Another option is the use of blinds and these will need to be motorized or at least all the ones I have seen are motorized. This will allow you to cut off the hot sun in the summer.
Vented Skylights are great for getting hot air out of your home to reduce your need for air conditioning. Convection will work on its own and a fan blowing in from a window will aid the convection. The problem you will have is this will only work for part of the year or part of the day. Additionally any vented skylight will require more maintenance. They are more likely to leak in rain and snow conditions because they depend on gaskets in addition to flashing.
The option of venting must be considered overall based on your location and the benefit it will bring. You will also pay a premium of maybe 25% for vented over non vented models.
Since we already talked about vented models you can understand pretty quickly that a fixed unit has less of a chance to leak. It also will come with the option for blinds and it is often suggested in areas that get higher snow levels.
Dome Vs Flat Panel Skylights
Dome Skylights are made out of polycarbonate plastic which is strong and includes a UV protection but like all plastic will break down over time. They are best installed on roofs that have a low pitch or are flat. Some can be flush mounted and others require the installer to build up a shoulder out of lumber that is flashed and then the skylight is mounted to that instead of the roof decking. You can find units that have a raised curb to fit your roof so the contractor doesn’t need to build this part of the unit.
Flat Panel Skylights are best on high pitched roofs and can be flush or curb mount which is the shoulder that the contractor will need to build and flash. They come in plastic and glass and offer features such as venting and shades.
Final Note
What ever model you pick for your home the best thing to do like our friend is to visit with neighbors that have these units installed. Ask them about the options they had to choose from and how they feel about them overall.
Remember having a skylight is not a permanent situation. You can always change your mind and have it removed and then have the opening sealed with plywood. On the other hand they will need to be replaced more often than a standard home window especially the plastic units. Flashing will be a concern over the years and like our friend its not a bad idea to just replace the units if you are having a new shingle roof installed because better flashing and features will most likely make it worth the cost.