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ALGAE, FUNGUS, LICHENS, MOSS
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ATTIC CONDENSATION CAUSE & CURE
BARK SIDE UP on DECKS & STEPS
BEST CONSTRUCTION PRACTICES GUIDE
BRICK VENEER WALL LOOSE, BULGED
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BOOKSTORE - EXTERIORS
CAULK GUN TYPES, CHOICES
CAULKS & SEALANTS, EXTERIOR
CHIMNEY INSPECTION DIAGNOSIS REPAIR
DECK & PORCH CONSTRUCTION
DEFINITIONS of ENGINEERED WOOD OSB LVL etc
EIFS & STUCCO EXTERIORS
ENGINEERED WOOD Products
EXTERIOR WALL SIDING TRIM & FINISHES
FLASHING MEMBRANES PEEL & STICK
FLASHING ROOF WALL DETAILS
FLASHING SIDING DETAILS
FLASHING WALL DETAILS
FLASHING WINDOW DETAILS
FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
GALVANIC SCALE & METAL CORROSION
GLUES ADHESIVES, EXTERIOR CONSTRUCTION
GUTTERS & DOWNSPOUTS
HOUSE PARTS, DEFINITIONS
HOUSEWRAP / SHEATHING WRAP
ROOF ICE DAM LEAKS
INSECT INFESTATION / DAMAGE
LEAD POISONING HAZARDS GUIDE
LEED GREEN BUILDING CERTIFICATION
LOG HOME GUIDE
MOISTURE CONTROL in BUILDINGS
ODORS GASES SMELLS, DIAGNOSIS & CURE
PAINT & STAIN GUIDE, EXTERIOR
PORCHES & Sunrooms
PORCH CONSTRUCTION & SCREENING
RETAINING WALL DESIGNS, TYPES, DAMAGE
ROT RESISTANT LUMBER
ROT, TIMBER ASSESSMENT
SHEATHING, GYPSUM BOARD
SHEATHING, FOIL FACED - VENTS
SIDING TYPES, INSTALLATION, DEFECTS
SINKHOLES, WARNING SIGNS
STAINS on & in BUILDINGS, CAUSES & CURES
STAINS on CONCRETE
STAIN DIAGNOSIS on BUILDING EXTERIORS
STAINS on STONE, DIAGNOSE & CURE
STAIRS, RAILINGS, LANDINGS, RAMPS
STONE SURFACE CLEANING METHODS
STRESS SKIN INSULATED PANELS
STRUCTURAL DAMAGE PROBING
STUCCO WALL METHODS & INSTALLATION
SURFACE GRADING, SITE DRAINAGE
TEST KITS for DUST, MOLD, PARTICLE TESTS
THERMAL EXPANSION CRACKS in BRICK
THERMAL EXPANSION of MATERIALS
TRIM, EXTERIOR CHOICES, INSTALLATION
TRIM, INTERIOR INSTALLATION
VAPOR BARRIERS & CONDENSATION in BUILDINGS
VENTILATION in BUILDINGS
VINYL CHLORIDE HEALTH INFO
VINYL SIDING or WINDOW PLASTIC ODORS
VOCs VOLATILE ORGANIC COMPOUNDS
WATER BARRIERS, EXTERIOR BUILDING
WATER ENTRY in BUILDINGS
WINDOWS & DOORS
Vinyl siding defect recognition & diagnosis:
This article discusses common defects observed in vinyl exterior building siding, such as buckling, splitting, cracks, odors, and questions about the need for a vapor barrier behind vinyl siding and over building sheathing. Included are comments from several recognized building inspection and construction authorities.
Our page top photo shows wrinkled vinyl siding - often caused by heat exposure such as from a BBQ Grill - but in this location the pattern and size of the damage made us suspect that there was another cause.
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In our photo at above left it looks as if there is a problem with moisture behind the siding, leaking out at two of the siding panel bottom edge vents, long enough to invite a pair of algae colonies on the wall.
We suspect that that top J-channel trip at the gable end protrudes past the gable board and is not sealed.
Wind-blown rain entering behind any building siding material can become a water problem.
Article Series Contents
Our photo of leak stains on a foundation wall below vinyl siding (above right) suggests that either we had wind-blown rain or other exterior leaks into the building wall or there was an in-building leak or flood such as from a burst pipe.
Water passing over wood and other building materials but behind the vinyl siding can easily pick up pigments that stain the foundation wall outside.
If the builder failed to install a weather barrier, this sort of staining is more likely. See WATER BARRIERS, EXTERIOR.
Most of the vinyl siding problems we see appear to be due to poor installation details, though on occasion we see cracks and breaks that may be blamed on older, more brittle vinyl products.
Our photo (above left) demonstrates impact damage to vinyl siding, in this case just above the floor of an outside deck.
Our second vinyl siding damage (above right, courtesy of Carson Dunlop Associates) demonstrates an impact damage even to siding that made both a hole and a crack in the wall covering. With (often older-generation) more brittle vinyl wall siding products we often find impact damage and holes caused by stones kicked-up against the wall by a lawn mower or weed-wacker.
Our vinyl siding caulk photo (above left) shows a combination of improper trim installation, building leaks, caulk where it is not helping, and even the caulk was so sloppily applied that it didn't seal anything.
Our photo at above right shows cracking vinyl siding above a window corner - a bad place for a leak that can lead to building water entry, window damage, and even hidden mold.
In our photo at above left it looks like really sloppy J-channel work during siding installation, leaving a leak at the window sill.
Watch out: J-Channel errors can rot windows and doors: Our photo of improperly-cut J-channel trim around a window (above right) shows a more serious problem than may be immediately apparent. In Spackenkill, Poughkeepsie, NY we found an entire neighborhood of homes in which nearly all of the windows were rotted beyond repair due to this error.
Wind-blown rain sent inside the J-channel trim and into the window structure was the problem caused because the installer didn't follow the manufacturer's instructions. Properly the top J-channel is trimmed to include a tab bent over the vertical J-channel to route water outside, not inside the trim. See Figure 1-25 for details.
Common sources of stains on vinyl siding include formation of algae, fungus, lichens, dirt accumulation on damp surfaces, rain splash-up soil, even smoke from nearby barbecues or fires.
Details about stains on vinyl siding are now found at VINYL SIDING STAINS
More about building wall stains can also be found in these companion articles:
Below our photographs show what happens to loose, poorly-secured vinyl siding on a home. These pictures were taken just about a year apart. We had watched the loose buckling siding on this Poughkeepsie NY home for some time. Finally after a windstorm much of the gable end siding has simply been lost completely.
Below are additional examples of poorly-attached siding (below left) and siding that was literally pulled off of the building when an adjoining stucture itself collapsed. The consequences of the failure at right were more serious than met the eye: this wide opening into the building wall allowed rain to soak the wall interior, leading to costly mold, rot, and insect damage to the structure.
In our photo at above left demonstrates a loose siding panel that is inviting more serious wind damage. Our second photo (above right) demonstrates a combination of poor siding installation, improper lower-roof flashing, a home that sat for months unattended while wind, rain, and snow penetrated the structure. These are almost certainly construction and installation defects, not product defects.
Detailed specifications for hanging vinyl siding to avoid buckling and blow-offs are found in our article VINYL SIDING INSTALLATION - see:
Vinyl siding that buckles due to improper nailing (photo shown above left) is is not normally extremely wrinkled, and will be more wavy across longer horizontal runs of surface.
A Complete Guide to Rippled, Buckled, Bent Vinyl Siding is at:
As our buckled vinyl siding at ground photo (above left) and Carson Dunlop's photograph vinyl siding photo shows (below left), bringing vinyl siding down to ground contact or even below ground may please the architect or home owner's sense of aesthetics, but it is an engraved invitation to wood destroying insects to attack the structure.
We like to see 6-8" of clear foundation wall between the bottom of wall siding and the top of the ground surface. Adding mulch as was done here, increases the invitation to termites.
Watch out: Information about vinyl products (not just siding) that may produce odors or have other environmental concerns can be found at
It's not unusual to need to re-hook loose vinyl siding such as shown in our vinyl siding damage photo above, or to remove impact-damaged, heat damaged, or badly stained vinyl siding from a structure.
In fact we might try removing and re-nailing vinyl siding on a building wall that buckles every time the sun shines on it.
Brute force can un-hook vinyl siding in the middle of a wall from the course below and course above, in order to pull nails and take off a bad siding section.
But without a siding replacement tool such as Malco's Side Swiper SRT1 shown in our photo (left), re-hooking the bottom edge of the new siding section to the top of the course below can be almost impossible.
The hook on this tool is designed to loosen and then help re-lock the bottom edge of vinyl siding without cutting or damaging the siding.
A few home inspectors also carry this siding replacement tool to permit invasive inspection of a building wall - something not normally done during a visual home inspection for a purchaser.
A newer version of this tool, the Malco SideSwiperII (SRT2) has a nicer handle that makes unlocking and re-locking of vinyl siding easier and less likely to be damaged.
Continue reading at VINYL SIDING BUCKLED WARPED or select a topic from the More Reading links shown below.
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Frequently Asked Questions (FAQs)
Question: Chalking surface of older vinyl siding - is this normal
I am wondering why when I rub my fingers across our siding I come away with my fingers being white. Is this a normal vinyl siding thing or does it mean it has been previously painted or what? I want to clean the siding but would like to know what the white stuff is first. - Anon 8/18/2011
Watch out: any older oxidized plastic may have increased in brittleness and be more vulnerable to mechanical damage.
Question: I found carpenter ants behind my siding - how do I fix the problem
after i took down insulation i found a lot of carpenter ants ,killed them . investigated more around the house noticed in the garage that there were more took down sheet rock water damaged. j channel cut and holes with wood showing .how do i fix this? - Dale 7/21/12
Dale you're going to need to follow the water backwards until you've found the leak or water entry point; fix that, and restore the siding; You'll need the "siding hook" siding replacement tool we describe if you're working from the bottom of the wall up.
Question: Mike diagnoses rippled vinyl siding
(Sept 18, 2012) Marc said:
I had vinyl siding installed to replace my cedar siding. They removed the cedar to install the vinyl. The sheathing was gypsum board and while removing the cedar siding, much of it was damaged (holes, tears, etc.). Instead of replacing it, they just covered the sheathing with a thin foam barrier. They also caused additional damage that I was able to find in my attic where they missed hitting studs and blew out holes in the sheathing. Should they have just covered up damage? Is it reasonable to ask them to remove the siding to inspect and repair all damaged sheathing?
Nov 27, 2012) Mike in Michigan said:
[quote]The picture with the dryer vent below the window was caused by the reflection of the sun off the window. I would put $$$ on it. - Jim Hilt 9/11/2011[/quote]
On the contrary! As the sun rises in the sky, the reflected light and heat move downward on the wall. That softening pattern is exactly where it should be. When the window and adjacent wall are so close together (and always facing south and west), no breeze carries the hot air away. Between the direct sun and the reflected sun, you get high temperatures on the surface, but it's rare to see damage from it, because usually airflow cools the surface off. When you put them too close together like this (and again, oriented to the sun just-so), the pocket of dead air allows temps to get even higher and you see the damage shown.
Thanks very much for the excellent analysis of rippling vinyl siding caused by reflected heat from windows. I've added your comments to the article above in the FAQs section.
If you want to be identified as a technical reviewer/editor, contact me using the CONTACT US link.
Question: snow damage to vinyl siding ?
(Apr 21, 2014) Anonymous said:
Does snow accumulation against vinyl siding cause any damage to the siding?
Snow is unlikely to damage vinyl siding. However, melting snow piled against vinyl siding means there is a risk of water penetration into the wall structure - which could be a source of damage: rot, mold, pest infestation.
(Oct 24, 2014) Pausha said:
The brand new house that we are planning on buying, has the vinyl siding sealed to the very bottom to the concrete slab by mortar. Is that right? Our home inspector thinks that it should have some kind of gap for the water to pass, to avoid water damage. Thoughts?
Pasha your home inspector was on target. Clearance space is to avoid both rot and insect damage.
(Nov 24, 2014) Fred said:
I have a side entrance door to the garage. Rain water is rotting the bottom of the door frame on the hinge side. Where can this be coming from? I already replaced the door frame once.
Fred, that sounds as if there may be both door head flashing and side flashing errors and framing or trim details trapping water in the structure.
Question: siding falls off the house or is easilyh pulled off
12/11/2014 Amanda said:
Hello. We had vinyl siding installed and now peices have falled off or are bowing out. We had a friend come over who we found out does it as well and he ended up placing two fingers under the siding and pulled and it popped off. IS it supposed to do that?
NO Amanda certainly not. It sounds as if siding on your home was nailed to some sort of soft sheathing such as fiberboard and it missed the wall studs. Better ask an experienced siding contractor to take a look to see what's needed before more blows off.
Keep us posted. Send along photos if you can (see our CONTACT US link) and I can comment further.
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