Stone Siding, Rampant Installation Defects

Home Inspector with Structure Tech Home Inspections

Without a doubt, the sexiest new siding being used on the front of houses is stone siding.  I say stone siding because that's what everyone calls it, but what I'm really referring to is Masonry Veneer.  This is a man-made product that's meant to look like stone siding, and is installed in a similar manner to stucco.

Masonry Veneer

While masonry veneer looks great, it's susceptible to the same moisture problems that stucco is.  Moisture testing experts in the Twin Cities agree that this product has experienced the exact same type of moisture intrusion problems as stucco.   Building science expert Dr. Joseph Lstiburek  actually calls this product "lumpy stucco," because that's essentially what it is.

While newer stucco installations are done quite well, the folks installing masonry veneer seem to have a lot of catching up to do on proper installation details.  When I inspect masonry veneer, I use the Masonry Veneer Manufacturers Association's installation guide, which you can find here - MVMA installation guide.  This guide is packed with diagrams showing how to install the material, based on generally accepted methods.

I find the same installation shortcomings over and over.  To help illustrate these issues, I've taken several installation diagrams from MVMA's guide and edited them down to more clearly illustrate where the installations went wrong.  As a home inspector, I don't get to see all the different layers of materials that get installed behind the masonry veneer; my inspection is limited to what I can see on the surface, and that's what I report on.  To make the installation diagrams easier to understand, I've removed the labels of all the components that aren't visible during the course of a home inspection.

Too close to grade or hard surfaces

Masonry veneer should be kept at least 2" above hard surfaces, such as concrete, and 4" above the soil.

ACMV - required height above grade or paving

When the material is buried in dirt, water can wick up in to the material and cause rotting at the wall.

ACMV - too close to grade

There should also be a 2" gap to paving, but this is rarely done - especially on columns.

ACMV - too close to concrete

Of course, leaving a 4" gap at the ground isn't the prettiest looking thing in the world, but there is a solution; simply have the weep screed terminated at least 4" above the ground, and have another layer of masonry veneer installed below it, as shown in the diagram below.

ACMV - Alternative finish at grade

The photo below shows this detail done properly.

ACMV - Alternative finish to grade photo 1

Here's a close up - note the weep screed.

ACMV - Alternative finish to grade photo 2

Improper Vertical Transitions

When masonry veneer has a vertical transition to something like wood trim, windows, or other siding materials, it should have a 3/8" gap left between the two different materials.  This gap needs to have a foam backer rod pushed behind it, and then filled with sealant to help prevent water intrusion.  This is rarely done.

ACMV - Vertical transition requirements

ACMV - too close to different siding

ACMV - Window transition requirements

ACMV - too close to window

Clearance to roof coverings

Masonry veneer needs to be kept 2" above roof surfaces to help prevent water from wicking up in to the wall.  The photo below shows a common deviation, where the masonry veneer actually touches the shingles.  This is just asking for trouble.

ACMV - required clearance above roof covering

ACMV - too close to shingles

Improper Vent Penetrations

Dryer vents, kitchen exhaust vents, bath fan vents, and other similar vent terminals should be pushed up against a bed of sealant, but they're often buried in masonry.  What happens when the vent cover gets broken and needs to be replaced?

ACMV - Dryer Vent Penetration

ACMV - dryer duct buried

Improper Sillcock Installations

Just like dryer vents, exterior sillcocks (aka - faucets or hose bibs) need to be embedded in sealant on the surface of the masonry veneer, not buried behind the veneer.  What happens when the faucet needs to be replaced?

ACMV - Pipe Penetration

How many bloody knuckles will this installation cause?

ACMV - buried sillcock

The nice thing about the installation shown above is that they got the vertical transition correct - check out that thick bead of caulk.

Of course, this is only a partial list of the things that can go wrong on a masonry veneer installation.  If you're planning to have this material installed on your home, make sure the MVMA's installation instructions are followed to help lower the potential for water intrusion.  If you're buying a home with masonry veneer already installed, treat it the same way you would stucco - consider having invasive moisture testing done.

Comments (49)

Carol Fox
Allen Tate Company 704-905-3935 - Matthews, NC
Helping You Discover Charlotte's Best Small Towns

Hi Reuben,

This is great information.  My neighbors found out the hard way that what you are noting is true.  They had stone siding on the front of their house.  When they sold recently, they discovered that there were moisture problems behind it.  They had to take about a third of it off, repair the rotted wood and then reinstall.  It was amazing to see how much rot was around some of the windows when the siding came off.

We use a lot of stone siding in my market.  I'm sure this will start to come up just like the synthetic stucco issues of the 1990s.



Sep 05, 2012 10:23 PM
Woody Edwards
First Choice Realty, Inc - Chesterfield, VA
A Realtor® Who Answers His Phone!

Thank goodness, this material hasn't come to our area yet, as far as I know!  It does look good, BUT..........

Sep 05, 2012 10:42 PM
Clint Mckie
Desert Sun Home, commercial Inspections - Carlsbad, NM
Desert Sun Home, Comm. Inspection 1-575-706-5586

Hi Rueben,

I see this same stuff here. But we are in a dryer climate. Problem is though the stone is still installed incorrectly.

Tell that to the contractor and you might get shot here. LOL

Theyu don't take very kindly to being told they were wrong.

Have a great day and a very good post. Congrats on the FEATURE.

Best, Clint McKie 

Sep 05, 2012 10:58 PM
Robert Sole
REM Inspections LLC - Winter Springs, FL

If they can slap it up on the wall and make it stick, do you really expect them to take the time to read the installation manual?  Unfortunately, that is why so many of these problems occurr.  Good post.

Sep 05, 2012 11:25 PM
Marshall Brown
Mid America Inspection Services, LLC - Fargo, ND

Now I have to wander around all day wondering if I have missed any of these requirements, thanks!


Really, great blog and important information sincee I am seeing more of this type material being used.

Sep 05, 2012 11:27 PM
Rafi Footerman
Mid Jersey Inspections - Edison, NJ
Home Inspector, Mold Inspector, Radon and More!

Very well illustrated.  It's hard to explain this to many clients and there's always push back from the sellers. As Jay stated, if the town officials approved it (incorrectly), the seller doesn't want to address it.

Sep 06, 2012 12:34 AM
Kimo Jarrett
Cyber Properties - Huntington Beach, CA
Pro Lifestyle Solutions

Seems like a only a very skilled masonry person should be installing this type of wall, so the cost justification must be deemed affordable when comparing this material to other exterior wall options, right?

Sep 06, 2012 12:40 AM
Lyn Sims
Schaumburg, IL
Real Estate Broker Retired

Wow, better not skimp on installation but it doesn't seem that people know what they are doing. Weekend warriors are not doing a great job.

Sep 06, 2012 01:38 AM
Joe LaVallie
HomeStreet Bank - Mountlake Terrace, WA

Great information-especially for you Seattle buyers. Yes it does rain here that much.

Sep 06, 2012 02:50 AM
Sharon Sanchez
Ace Home Realty - Carson, CA
Your Number "1" Source For Real Estate.

This is good information know.  Thanks.

Sep 06, 2012 07:32 AM
Gene Riemenschneider
Home Point Real Estate - Brentwood, CA
Turning Houses into Homes

Great post.  Many of us would not even think of these details.  Nice stuff to learn.

Sep 06, 2012 07:57 AM
Reuben Saltzman
Structure Tech Home Inspections - Minneapolis, MN
Delivering the Unbiased Truth.

Nan - or at least obtain, read, and follow the installation instructions, right?

Donald - thanks, good chatting with you last week.  We never finished our conversation though... call me any time.

Catherine - thanks.

Richie - ha!  You're too kind.

Liz and Bill - I completely agree.  I can't think of a better look for the front of a house, but jeeze... that stuff is easy to install wrong.

Sep 11, 2012 08:26 PM
Reuben Saltzman
Structure Tech Home Inspections - Minneapolis, MN
Delivering the Unbiased Truth.

Mike Y - I'm glad to hear it.

John W - Good question about the weep screed, drip screed, or casing bead.  I'm guessing it's poorly written, and should have said one of these is required.

 Goran - definitely.

Harry - agreed.  This stuff isn't that tough to put up though - I've seen many homeowner installations of this material that actually turned out looking quite nice.     Looking.

James - just wait.  It's coming.

Sep 11, 2012 08:30 PM
Reuben Saltzman
Structure Tech Home Inspections - Minneapolis, MN
Delivering the Unbiased Truth.

Steven -  I agree!  

Bob - I'm guessing we'll start seeing better installations as more and more houses start to fail, just like stucco.

Carol - you're exactly right.  Lumpy stucco.

Woody - when it does, you'll be ready for it.

Clint - bad times!  It's hard for the contractor to argue when you have a nice diagram that directly contradicts their work... but they still try, of course.

Sep 11, 2012 08:34 PM
Reuben Saltzman
Structure Tech Home Inspections - Minneapolis, MN
Delivering the Unbiased Truth.

Robert - exactly.  It's not tough to stick this stuff on the walls.  I've heard many people call this product "lick-em stick-em" stones.

Marshall - yeah, I feel like I wonder the same thing about all of my past inspections every time I learn something new :)

Rafi - In many cases, it's not something that is going to be fixed.  It's just one of those cases where the buyers need to be aware that it was done improperly, and will have a greater potential for failure.

Kimo - believe it or not, this product is quite easy to install.  It's a popular project for DIYers... 

Lyn - the contractors are having a tough time getting it right as well.  Most of those photos above came from new construction homes!

Sep 11, 2012 08:38 PM
Reuben Saltzman
Structure Tech Home Inspections - Minneapolis, MN
Delivering the Unbiased Truth.

Joe - I've heard you get a little rain now and then...

Sharon - thanks.

Gene - you'll start noticing these installation defects everywhere now.

Sep 11, 2012 08:39 PM
NJ Roofing

Nice work.

Sep 14, 2012 06:35 AM
Reuben Saltzman
Structure Tech Home Inspections - Minneapolis, MN
Delivering the Unbiased Truth.

NJ Roofing - thanks.

Sep 18, 2012 08:09 PM
Wayne B. Pruner
Oregon First - Tigard, OR
Tigard Oregon Homes for Sale, Realtor, GRI

I really like the look of stone veneer, but I am not sold on it's long term viability yet.

Nov 14, 2012 12:17 PM
Reuben Saltzman
Structure Tech Home Inspections - Minneapolis, MN
Delivering the Unbiased Truth.

Tigard - think stucco.  I think this stuff will last for a long time.

Nov 14, 2012 06:48 PM