Siding in Bend
Bend sits on the dry east side of the Cascades, and its weather is hard on siding in a different way from the wet west side of Oregon. There's far less rain, but the temperature swings widely between day and night, and the wall freezes and thaws over and over through the cold months. Siding that fails here usually cracks, shrinks, fades or opens at the joints rather than rotting from constant rain.
The nearest weather station
NOAA has no engineering weather station in Bend itself. The nearest one is at Redmond, about 15 miles north, at Roberts Field (elevation 3,078 feet). Its figures are a guide to Bend's conditions, not measurements taken in Bend:
- about 125 freeze-thaw cycles in an average year;
- a 99% winter design temperature of 9°F;
- a 1% summer design temperature of 89°F, with a mean coincident wet-bulb temperature of only 60°F;
- no hours in an average year with the wet-bulb temperature at 73°F or higher, and about 36 hours at 93°F or hotter;
- a 100-year rainfall rate of 1.0 inch per hour.
That's a dry climate with a lot of freezing. About 125 freeze-thaw cycles a year is a large number, so any water that does get into the wall, from snowmelt, a sprinkler or a gap at a window, gets frozen and thawed many times.
What the swings do to siding
Big temperature swings make siding materials move. Vinyl expands and contracts more than most materials. Wood shrinks in dry air and swells when it gets wet. Fiber cement and engineered wood are steadier, but their joints and cut ends still need care. Ask each bidder:
- how they fasten the product so it can move without buckling or pulling loose;
- how wide they leave the gaps at ends and trim, and what they seal them with;
- whether paint or stain on the material they propose stands up to strong high-desert sun;
- how they'll handle the cut ends of fiber cement or engineered wood.
Snowmelt and the bottom of the wall
Snow that sits against the house melts on sunny afternoons and freezes again at night. The bottom courses and the spots where a roof sheds snow onto a wall take the most of that. Ask about clearance between the lowest course and the ground, kick-out flashing where a roof edge meets a wall, and how the siding will be finished above decks and patios.
Behind the siding
A good siding job is mostly about what you don't see. Ask about the water-resistive barrier and how its seams are lapped, flashing above windows and doors, and whether there's a drainage gap behind the siding so any water that gets in can drain and dry. In a dry climate a wall dries out quickly once water can escape, which is a good reason to make sure it can.
Oregon's contractor rules
Oregon law requires anyone who undertakes, offers to undertake or bids on work as a contractor to hold a current license from the Construction Contractors Board, with a residential endorsement for work on a residential structure. Oregon requires a residential general contractor to carry a $25,000 surety bond and at least $500,000 in general liability insurance, and a residential specialty contractor a $20,000 bond and at least $300,000 in liability insurance.
Before you sign, look the contractor up on the CCB license search, check for a residential endorsement, and ask which kind of contractor they are registered as. Keep the CCB number with your contract.
Comparing bids
Ask every bidder to price the same scope: the siding product and its grade or thickness, removal of old siding, sheathing repair pricing, the weather barrier, flashing, trim, soffit and fascia, paint or stain, cleanup, the permit if one is needed, and the product and workmanship warranties. Compare line by line. A low bid that leaves out flashing or the barrier isn't pricing the same wall.