7 Siding Installation Mistakes Minnesota Homeowners Should Know Before the Siding Goes Up

New siding can look perfect the day the crew pulls out of your driveway and still be wrong. The siding installation mistakes that cost Minnesota homeowners the most are rarely crooked courses or a sloppy caulk line. They are behind the siding: housewrap that does not drain, flashing that was skipped or layered backward, a missing kickout where a roof meets a wall, fasteners driven wrong for the product, no room for the material to move, siding set too close to roofing, concrete or the ground, and new siding nailed over sheathing that should have been repaired first.

Most of those are invisible within hours. Then a Minnesota year goes to work on them: a swing that can top 100 degrees between the coldest winter night and the hottest summer afternoon, freeze-thaw cycles, wind-driven rain, and snow packed against the wall for months.

I have owned Northern Exteriors since 2001. This is the list I would want a homeowner to read before signing a siding contract, or while the house is stripped and there is still time to look. Plenty of crews do this right. You should simply know what right looks like.

One ground rule: different siding products have different rules. Every number below comes from the manufacturers’ and the State of Minnesota’s own published documents, checked in September 2026 and linked at the bottom.

1. Treating the Siding as the Waterproof Layer

Siding sheds most of the water. It was never designed to stop all of it. Wind-driven rain gets behind every kind of lap siding. What happens next depends on a layer you will never see again: the water-resistive barrier, or WRB, usually housewrap, lapped like shingles so water that gets in runs down and back out.

You do not have to take a contractor’s word for this, mine included. The vinyl siding industry’s own installation manual states that vinyl siding is an exterior cladding, not a water-resistive barrier, and is not a watertight covering. LP requires a properly installed WRB behind LP SmartSide. And the Minnesota Residential Code requires a water-resistive barrier over the sheathing of all exterior walls.

A Minnesota-specific wrinkle: fan-fold foam, the thin accordion-folded board you often find under older vinyl siding. The Minnesota Department of Labor and Industry’s re-siding fact sheet says fan-fold is not a substitute for the WRB unless the building official has approved that specific product and installation. If a bid lists fan-fold and never mentions housewrap, ask about it before you sign.

2. Window and Door Flashing That Relies on Caulk

A bead of caulk around the trim is not water management. Caulk is a maintenance item, and Minnesota freeze-thaw cycles are hard on it. Flashing is layered so each piece laps over the one below and gravity does the work. Minnesota’s code calls for corrosion-resistant flashing at the head and sides of window and door openings, applied shingle-fashion, and continuously above projecting trim.

Two details most homeowners would never know to look for:

• The gap above the window is supposed to be open. LP requires drip cap flashing above windows, doors and horizontal trim, with a 3/8-inch space between that flashing and the siding above it, and specifically says not to caulk that space. That gap is the exit. A well-meaning bead of caulk there turns a drain into a dam.
• Tape is not automatically flashing. The state’s fact sheet notes that tape used on housewrap seams does not count as flashing unless the housewrap manufacturer and the building official approve it for that use.

One honest nuance: on a re-side the windows usually stay in place, and the state does not require pan flashing under existing windows. That makes the head flashing and the way the housewrap laps around each opening matter more, not less.

3. Roof-to-Wall Intersections: No Kickout, and Siding Sitting on Shingles

Where a roof edge ends against a wall, all the water running down that joint arrives at one spot. Kickout flashing is the small angled piece at the bottom that throws it into the gutter. Without one, the water runs behind the siding, and the rot gets found years later.

Here is the part almost nobody tells Minnesota homeowners: under Minnesota Rules 1309.0903, kickout flashing is required when an existing house is re-sided, but not when it is only re-roofed. A home can be legally re-roofed with no kickouts. The siding project is when the requirement lands, so a siding bid on a house with roof-to-wall intersections should mention them.

Clearance matters here too. LP’s instructions require at least 1 inch between the siding or trim and the roofing, step flashing with an upper leg of at least 4 inches, and siding and trim kept out of the kickout itself. Siding resting on shingles wicks water, and in Minnesota that edge also sits in snow for much of the winter.

We covered the roofing side of this joint in our sidewall step flashing article and in the companion piece to this one, 5 Roof Installation Mistakes Even the Inspector Won’t Catch.

4. Fastening Every Product the Same Way

This is where different products have opposite rules.

Vinyl siding is hung, not pinned. The industry manual calls for fasteners centered in the nailing slot with the head left about 1/32 of an inch off the panel, roughly the thickness of a dime, so the panel can slide as it heats and cools. The manual says not to face-nail it. Vinyl nailed tight buckles on the first hot day, no matter how good the vinyl panel itself is.

LP SmartSide is the reverse. LP’s lap siding instructions call for nails driven snug to the face, not overdriven, using hot-dip galvanized nails or an equivalent that resists corrosion. They also have to be long enough to reach LP’s required penetration into framing or structural sheathing. An overdriven nail breaks the factory surface and gives moisture a way in. LP publishes a correction chart for exactly that.

Steel siding has its own fastening schedule. Same nail gun, completely different rules, and the mistakes show up when a crew treats one product like another. It is warranty territory too: LP states that its limited warranty does not apply to product affected by a failure to follow the instructions.

5. No Room for the Siding to Move

Everything on the outside of a Minnesota house moves with temperature. How much, and what to do about it, depends on the material.

• Vinyl moves the most. The industry manual calls for a minimum 1/4-inch clearance at all openings and stops, increased to 3/8 inch when the siding is installed below 40°F. That matters here, because a lot of Minnesota siding goes up in cool weather. A panel cut tight in October has nowhere to go in July.
• LP SmartSide moves far less, but it is not zero. LP requires a minimum 3/16-inch gap at butt joints and where siding meets trim, finished by one of LP’s approved methods such as sealant or joint moulding, and every field-cut end sealed. Boards jammed tight together are how edges swell and joints peak.

There is no universal siding gap. The mistake is applying one number to every material.

6. Bad Clearances at the Ground, Concrete, Decks and Roofs

Engineered wood has to stay out of standing water and off materials that hold moisture. LP’s current lap siding instructions call for:

• at least 6 inches between the siding and finished grade
• at least 1 inch above porches, patios, decks and other walking surfaces, with a narrow exception for certain covered, sloped surfaces
• at least 1 inch above roofing
• no direct contact with concrete, brick, stone or stucco
• a 3/8-inch space above horizontal flashing

Minnesota makes each of those matter more. Snowbanks sit against the wall for months, meltwater splashes off concrete, and landscaping slowly raises the grade. Vinyl and steel have their own requirements, so ask for the instruction sheet for your product. If your grade is already too high, have that conversation before the contract, not after the bottom course hides it.

7. Covering Up Damaged Sheathing

Tear-off day is the one day in decades when anyone can see the wall itself. The state’s re-siding fact sheet is direct about it: once the siding is removed, rotted or damaged sheathing, framing and insulation must be replaced, and the city may want to inspect those repairs before work continues. LP adds that siding should not be applied over rain-soaked or buckled sheathing.

This rarely goes wrong out of bad intent. It is schedule pressure plus a contract that never priced the repair. Ask before you sign how sheathing repair is handled. A per-sheet price or written allowance means nobody has a reason to look the other way. The usual suspects: below windows, under roof-to-wall intersections and around deck attachments.

What Can a Homeowner Actually Check During a Siding Project?

Nobody is asking you to supervise the crew or climb a ladder. Take photos from the ground and ask questions at the end of the day:

• The housewrap before it is covered. Upper layers lapped over lower, seams taped, no tears.
• Window and door heads. Metal drip cap flashing above each one, with the housewrap lapped over the top of it, not tucked behind.
• Roof-to-wall transitions. A kickout at the bottom of each one, and siding held up off the shingles.
• What the tear-off exposed. Ask to see any soft or stained sheathing before it is replaced.
• The instruction sheet. Ask which manufacturer’s instructions the crew is following. A good contractor can pull them up on a phone.
• The permit. The state says permits are required for re-siding existing homes. Ask who pulled it and when the inspections are.
• Photos of each wall before it is covered. We document the hidden work on our projects for this reason. Once the siding is on, photos are the only record.

For the before-you-sign version of this list, our education site has a guide to questions to ask before hiring a siding contractor.

Does a Passed Inspection Mean Every Siding Detail Is Perfect?

No, and that is not a criticism of inspectors. The state’s fact sheet calls for an inspection of the housewrap and flashing, plus a final inspection when the job is done. That has real value: someone independent looks at the water-management layer before it disappears.

But an inspection checks code minimums at a moment in time. The inspector is not on site all day and cannot watch each nail or measure each gap, and the process varies by city. Manufacturer instructions go further than code in places, and the product warranty depends on them. The inspection and the contractor’s own documentation are two halves of the same job.

Frequently Asked Questions

What is the most common siding installation mistake?

Fastening: vinyl nailed too tight to move, or engineered wood with overdriven nails. The most damaging mistakes are water-management errors such as poorly lapped housewrap, missing head flashing and missing kickouts, because they stay hidden until there is rot.

Should housewrap be replaced when siding is replaced?

On a full tear-off, plan on it. Minnesota’s code requires a water-resistive barrier behind the siding, tear-off usually damages what is there, and some older homes never had one. The state calls for the housewrap and flashing to be inspected before they are covered.

Is kickout flashing required in Minnesota?

Yes, when a house is re-sided. Minnesota Rules 1309.0903 requires kickout flashing when re-siding, or re-siding and re-roofing together, on existing buildings. It is not required when a home is only re-roofed.

How can I tell if new siding was installed incorrectly?

Look for vinyl that ripples on hot days or will not slide side to side, LP joints with no gap or unpainted cut ends, nail heads sunk below the surface, siding touching shingles, concrete or soil, no kickout where a roof meets a wall, and caulk filling the space above window flashing.

Does a city inspection check everything behind the siding?

No. It looks at the housewrap, the flashing and the finished job, but it is a check of code minimums at one point in time, not of every fastener, gap or manufacturer-specific detail.

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Planning a siding replacement in the Twin Cities? We will inspect the exterior and walk you through the full scope: siding, trim, wall condition, flashing and the details above. We install LP SmartSide, vinyl and steel. Start with our Twin Cities siding contractor page, or see our Woodbury and Cottage Grove siding pages. Request a free siding estimate or call or text 651-230-5103.

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Sources, checked September 2026: Minnesota DLI re-siding fact sheet; Minnesota Rules 1309.0903; LP SmartSide lap siding instructions; Polymeric Exterior Products Association (formerly Vinyl Siding Institute) installation manual. Requirements differ by product line and change over time. Follow the current instructions for the exact product on your home and confirm permit details with your city.