The Exterior Connection Blog

The Exterior Connection Blog

Value of Vinyl

Vinyl siding is resistant to stains, peeling, rot, and dents; and scratches are not easy to see.

People may worry about the flame resistance of vinyl, which is actually polyvinyl chloride or PVC.  It might melt, but it won’t continue to burn without contact with the flame.

Vinyl ignites at about 700 degrees, Pine and paper ignite at around 450 degrees.  The fumes are not healthy to inhale,  but would tend to put the fire out.  The smoke is unhealthy, but there is less of it…The HCl it produces would create a warning smell or irritation long before a toxic amount can be inhaled.  This contrasts with carbon monoxide and CO2, the other products of burning PVC and any wood or paper products.  All three gases in the smoke tend to extinguish actual burning of the siding.

Firemen have felt that vinyl siding has helped to contain house fires, or to prevent an adjacent fire from involving the next house.  Of course the vinyl will sag and smoke where another siding would blister, peel or burn.

Airplane upholstery looks similar to vinyl fabrics, but it burns quickly and release phosgene gas, a poisonous gas that has been used in war but is now banned.

Vinyl siding is slightly insulating without our foam insulation.  It tends to protect from frost and condensation.  It is also an electrical insulator, so doesn’t need to be grounded from lightning or stray electric lines in a wildfire situation.

It is available in almost any imaginable color—nonfading, and in many different textures and patterns.  And you don’t ever need to paint it!!!!

Isn’t Steel Siding Better?

It doesn’t burn…but vinyl burns very poorly, creating gases that tend to put out the flames.  The vapors are irritating—no silent poisoning is possible, unlike carbon monoxide from burning wood, kerosene, or diesel.


Steel will dent, and is more difficult to install neatly.  Damage would likely require replacement of an entire wall.  Vinyl is easy to repair or replace.

The coating on steel can occasionally be scraped off.  Vinyl color is through-and-through or at least molecularly bonded, not baked-on, painted, or enameled.  Scratches on vinyl are hardly visible.  Vinyl siding provides some insulation all by itself.

What about seamless steel siding, like seamless gutters?  Once again, steel siding is harder to install perfectly.  “Seamless” is not entirely seamless.  It usually comes in fifty-foot rolls.  A curbside shaper guided by a human is not at all comparable to roller mills controlled by computer.  The half-block long roller mill can delicately shape siding without cracking or scratching the colored finish.  It will create uniform pieces that will fit together perfectly during installation.

Not that we recommend steel siding, except for customer preference, or danger of wildfire.  Hundreds of homes have been damaged or destroyed during the fire seasons of the last few years.  We certainly want to honor your choice of materials.

Moisture, the Invisible Homewrecker?

All houses have many sources of moisture, which can damage windows, interiors, exterior paint, and siding.  Protection is much better from outside moisture than inside moisture!

Sources of moisture: us humans, laundry, showers, cooking, humidifiers, gas heat or cooking.  It may come from the house itself:  wet plaster, or a wet or unexcavated basement.

Water vapor travels invisibly to drier areas and forms moisture or frost.  It may be on inside walls, on walls or ceiling, or as iceballs in an attic right below nails.  You may see water or ice on windows, moisture on the walls or floor of basements, or water blisters under the exterior paint.  This blistering can extend to damage the siding, making the paint peel; or cause rot, mildew, stained walls,  and sweaty windows.

Tyvek allows moisture to travel both ways.  Fome-cor allows mostly one-way travel, due to separate perforations. Remodelers often find moisture and rot under Tyvek–It is not completely resistant to water.  It would be little help under vinyl siding, especially in a wetter climate.