Reuben Saltzman

Problems with LP SmartSide® installations

LP SmartSide® is the new high-end siding of choice here in Minnesota.  It used to be stucco, but moisture intrusion problems with stucco siding made many high-end home builders start using James Hardie siding.  In the last few years, this his changed.  Today, I rarely see James Hardie siding used on new homes any more; builders are using LP SmartSide® instead.

For a head-to-head comparison, click on the following link for an in-depth discussion of James Hardie siding vs. LP Smartside, which Ryan Carey posted on this blog over a year ago.

LP SmartSide® is a great product that I have yet to find a single failure on, but I suspect I’ll be seeing failures soon enough, because I find installation errors on nearly every home I inspect.  If you install LP SmartSide®, don’t make these mistakes.  If you’re buying a home with LP SmartSide® or you’re having it put on your own house, watch out for these mistakes.  If you’re a home inspector… well, you see where I’m going with this.  Check this stuff.  These are the most common mistakes being made by installers today.

Missing Paint

Without a doubt, the most common installation error that I find with LP SmartSide® is missing paint at the cut edges.  The manufacturer requires all exposed surfaces to be primed and painted.

Unpainted cut edge

Unpainted edge above roof

Unpainted edge above window

Overdriven Nails

This is another common defect.  Here’s a small collage of overdriven nails.

Overdriven Nails

The diagram below shows the appropriate repair methods for overdriven nails.

LP Smartside Nailing Diagram

Insufficient Clearance

The manufacturer requires 6″ of clearance from the siding to the finished grade.  It seems that almost every home has one or two areas where this clearance requirement isn’t met.

Lacks required clearance to grade

The manufacturer also requires 1″ clearance to shingles.  This is usually done right, but not always.

Lacks required clearance to shingles

The manufacturer requires a 3/8″ gap above windows and other similar penetrations.

LP Smartside Diagram Clearance above window

This is rarely done.

Improper clearance above window

A 3/8″ gap is a BIG gap.  Even when a gap is left here, it’s usually not what the manufacturer requires.

Improper clearance above window 2

Improper butt joints

The manufacturer requires a 3/16″ gap at the end of each piece of siding.  This includes butt joints, and places where the siding terminates vertically against windows, doors, and other fixtures.

LP Smartside gap at inside corner

Lacks gap at siding end

Improper gap at butt joint

A 3/16″ gap is a pretty large gap.  Here’s what a proper 3/16″ gap looks like:

Proper gap at butt joint

Insufficient kickout flashing

Kickout flashing is a piece of metal at a roof end that prevents water from leaking into the wall.  See below.

Kickout Flashing

LP SmartSide® requires flashing to have a 4″ upper leg.  This means the kickout flashing needs to be 4″ high.  This usually isn’t done.

Kickout flashing too short

Joint Treatments

There are three options for keeping water out of the butt joints.  The first and second options are to have the joints caulked or have joint molding installed.

Butt Joint Treatments

The third option is to have flashing at least 4″ wide installed at the joints, as long as the ends of the siding are factory finished, and the siding is prefinished by an approved or preferred prefinisher.  That means no cut edges at the butt joints.  When field-cut edges are present, flashing at the joints is not an appropriate installation method.


That wraps up my list of the most common installation defects for LP SmartSide®.  Again, this is not a full list of defects.  For the full list of installation instructions, and for more information on this product, click here.   Why does this stuff matter?  Because if the product fails as a result of an improper installation, the manufacturer will not cover repairs.

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Author: Reuben SaltzmanStructure Tech Home Inspections



6 responses to “Problems with LP SmartSide® installations”

  1. Nick Zeman
    October 7, 2015, 12:08 pm

    You sure know your LP. You nailed all of the same things that I also see as a contractor in the field. The biggest problem with most things is not the product, but how it’s installed. Keep up the great work Structure Tech! Love reading these articles.

  2. Reuben Saltzman
    October 7, 2015, 1:47 pm

    Thanks Nick!

  3. Ryan Bretzel
    October 7, 2015, 12:32 pm

    Can you caulk the butt joint rather than leave exposed and painted?

  4. Reuben Saltzman
    October 7, 2015, 1:48 pm

    Yes, the joints can be caulked.

  5. Paul B.
    October 17, 2015, 4:02 am

    we are ready to install on new house for first time. Sent your article to my lead carpenter. All good points.


  6. Photos from New Construction Home Inspections, Part V | Structure Tech Home Inspections
    November 10, 2015, 6:41 am

    […] recently wrote an entire blog post on installation defects with LP Smartside, which I won’t repeat here.  All of those installation defects were from new homes. […]

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