Siding in Rochester
A Rochester house spends a large part of the year in real cold. Siding here has one main job: keep water out of the wall through a long winter, then let the wall dry out over a short summer. Most siding trouble in southeast Minnesota starts with water that got in during the cold months and had nowhere to go.
What the weather data says
Rochester has its own NOAA engineering weather station, at an elevation of 1,319 feet. Its figures describe the conditions a wall has to survive:
- a 99% winter design temperature of -12°F;
- a 1% summer design temperature of 86°F, with a mean coincident wet-bulb temperature of 72°F;
- about 58 freeze-thaw cycles in an average year;
- a 50-year ground snow load of 47 pounds per square foot.
Each freeze-thaw cycle works on any water sitting in a crack, a lap joint or a gap around a window. The water freezes, expands, thaws and soaks in deeper. Over a few winters a small gap becomes a soft board or a loose panel.
Cold-weather materials
Every common siding material can work here, but each one behaves differently at -12°F:
- Vinyl gets stiff and brittle in deep cold, so a hard knock from a shovel or a ladder can crack it. Ask about panel thickness and how the installer leaves room for the large expansion and contraction between January and July.
- Fiber cement handles cold well but must be sealed and painted at cut ends, because it can take up water there.
- Engineered wood needs the same attention to cut ends and to the gap between the bottom course and the roof or ground.
- Real wood needs regular paint or stain, and the paint has to go on in warm weather, which in Rochester means planning the job for the right months.
Ask each bidder which product they recommend for your walls and why, and ask for the manufacturer's cold-weather installation instructions.
Snow against the wall
With a ground snow load of 47 pounds per square foot, snow piles up against the bottom of the walls and stays there. Ask the contractor how much clearance they'll leave between the lowest course and the ground, decks and roof lines, and how they'll flash the spots where a roof sheds snow and meltwater onto a wall. Ice dams on the eaves can send water behind the top courses, so it's worth asking about gutters and the roof edge too.
Behind the siding
The weather barrier, flashing and trim details matter as much as the panels. Ask about:
- housewrap or another water-resistive barrier, and how its seams are lapped;
- flashing above every window and door, and kick-out flashing at roof-to-wall joints;
- whether the design leaves a drainage gap so the wall can dry;
- how they'll deal with damaged sheathing or framing found once the old siding is off.
The Minnesota license
Minnesota law requires a residential remodeler or residential building contractor license from the Department of Labor and Industry for anyone contracting with a homeowner to improve a home using two or more of eight special skills; siding, soffit, fascia and trim, stucco and gutters all fall under the exterior finishing skill. A contractor whose gross annual receipts from licensable specialty work do not exceed $15,000 may work under a certificate of exemption from DLI instead of a full residential license.
So a siding bid that also covers other skills may call for the full license. Ask the contractor which credential they hold, look the name up on DLI's license lookup, and make sure what shows there fits the work in the contract.
Hard water and lawn sprinklers
Rochester Public Utilities says its groundwater is very hard, at 17 grains per gallon (280 ppm), because the bedrock under the city is mostly limestone, and notes that hard water can leave film and mineral build-up. Sprinklers that spray a wall every evening can leave the same kind of residue on siding and trim. Aim them away from the house.
Comparing bids
Ask every bidder to price the same scope in writing: the material and its thickness or grade, removal and disposal of old siding, sheathing repair by the sheet, the weather barrier, flashing, trim, soffit and fascia, gutters if included, the permit and the product and labor warranties. Compare the line items, not only the totals, and ask what happens to the schedule if the job runs into cold weather.