We purchased a geodesic dome with five gables. We've had several people, including roofers, tell us that the roof has 3-5 years of life left. The roof has two layers of shingles (new laid on top of old). However, the more I dig into renovations the more I find wrong with it (pictures can be seen at: www.domeroof.wordpress.com) For example:
1. There was a fair amount of aluminum flashing used at the junction points between the dome and gables. I'm finding numerous cracks and holes in the flashing.
2. The flashing mentioned above was cut flush with the roof decking. As a result, the roof decking absorbed water and rotted, in some areas, as far back as the wall. This allowed water to run down the wall and rot the sill plates in some areas.
3. No eave starter strip or drip edge was used along the roof decking edges.
4. There are a few somewhat dark spots on the drywall inside, which indicates to me that there may be leaks.
5. Apparently, dry rot is a common issue in geodesic domes due to lack of ventilation in the roof. As is often the case, this roof does not have ventilation.
It appears to me that the best way to tackle these problems is to have a new roof installed and I have a few questions for people who may have experience with these types of structures.
1. The total roof surface area is about 2000 sq. ft. Does anyone have a ballpark estimate as to how much it will cost to properly install a new roof and flashing/eave drip edge? Some rotting wood will need replacement as well.
2. The gables have gable end vents. Is this enough? Or should ridge vents be installed?
3. Does anyone have information on new methods for ventilating this type of roof?
4. Does anyone know of a roofer in Northwest Washington State who is experienced in doing these roofs?
5. Can anyone offer recommendations on what kind of materials should be used on the roof (i.e. brand of shingles, type of underlayment (I would like something better than tar paper))
6. Do roofing companies offer a discount if the homeowners tear the old roof off?
Any other recommendations are welcome!