One thing about having shingles in the Northwest is that you have to get out the bleach a lot to knock down mold. We paint every other summer, but now it seems a lot of boards and shingles are damaged. I've heard there are also mold problems and warping with siding. Which is more cost-effective?
Izzy J. ~ Portland, Oregon
If the exterior of your home is not properly shedding rain water, then you are going to have mold and damage issues to deal with regardless of the type of siding that is on your house. Both shingles and lapp siding are prone to warping if the wood is constantly wet and does not get enough air and sunshine to dry the wood out. Worse yet, if rain water is getting behind the siding, you will probably have water damage issues with the siding and the underlying structure.
To protect your home's siding from the ever-present Portland rain, you should make sure that your home's gutter system is working properly. If the rain that falls from your home's roof is not collected by a working gutter system and diverted away from the house, the rain water can run down the side of the house and damage the siding. Another area that is prone to water damage is where a siding board meets a piece of trim, as water can infiltrate the seam between the two pieces of wood and then run down the wall of the house, under the siding. These seams need to be caulked with an exterior grade sealant so that rain sheds off the siding and does not cause this type of damage.
Once your home is properly shedding rain water, your annual paint job should last a lot longer and the siding should not be as prone to warping and mold build up. Good Luck!