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Frequently Asked Questions (FAQs)

What Causes the Ugly Roof Stains?

Black or very dark roof stains are caused by a hardy type of algae, Gloeocapsa magma (often referred to as blue-green algae), which grows on the roof and feeds on the limestone filler in asphalt shingles. Often the algae originates in standing water as well as in lakes and ponds. Wind, birds and other wildlife carry the algae spores to roofs from the water sources and then from roof to roof. Most of the stains begin on the north facing side of the roof where the lack of sun keeps the roof from drying out completely. The algae normally grows for quite some time before stains are noticed – 5 to 10 years is not uncommon. As the algae grows, it holds more moisture on the roof thus accelerating the growth process.

Green roof stains are normally caused by mold or mildew. Other stains are caused by fungus, lichen and moss.


If I am not Concerned about the Looks of my Roof, should I be Concerned about Roof Stains?

Yes, very much so.

Black roof stains are caused by a very hardy algae, Gloeocapsa magma. This algae is not just on the surface of the roof causing discoloration. It takes root in the asphalt shingles dislodging the protective roof granules that protect and color the roof. The algae feeds on the limestone filler in the shingles. It holds water to the roof's surface that can cause decay & rot of the roof's underlayment. Thus, not only is your roof being discolored by the algae, but it is shortening the life of your roof leading to an earlier than necessary, expensive roof replacement.

Other organisms such as moss, fungus and lichen can also cause damage to the roof.


How does ZincShield® work to keep stains off my roof?

As rainwater flows over ZincShield®, zinc ions are released from ZincShield® constantly coating the roof as they are carried down by the water flow. 


Will ZincShield® clean my roof of existing stains?

ZincShield® is not, as a general rule, intended to clean the roof (however it might do so over a long period of time).   ZincShield® is intended to be used to keep a roof clean.  

If your roof is currently stained, you do not have to clean your roof before ZincShield® can be installed. However, you should at least treat the roof chemically before installing ZincShield®.
Roof-Be-Clean® is an excellent product for cleaning a stained roof (see www.roofbeclean for complete details).

Chemicals that are used to clean roofs can cause discoloration of ZincShield® so it is a good idea to treat the roof prior to installation of ZincShield®.


If my roof is currently stained, how should I get it cleaned?

There are basically two ways to clean a stained roof – power washing/brush cleaning or application of no wash, specialty chemicals.

Power washing/brush cleaning is not recommended. Asphalt shingled roofing is coated with granules that not only protect the roof but also provide the colors for the roof. When the roof is power washed or brushed cleaned, it breaks the bond that holds the granules to the roof allowing them to wash away. Asphalt shingles are easily damaged as anyone who has walked on a roof can attest - just walking on the roof dislodges the granules. Also, when washing the roof, it is easy to get water up under the shingles, which should always be avoided. The use of high pressure washing and/ or brush cleaning is very damaging to the roof – the force of the high-pressure discharge and/or the brushing action does significant damage. Power washing is not even recommended for asphalt pavement so it certainly should not be used on asphalt roofing!

Specialty roof cleaning chemicals that do not require power washing are highly recommend since they do not cause damage to the roof. Roof-Be-Clean® is an excellent chemical roof cleaning product (see www.roofbeclean for further information).

The advantage of power washing is basically “instant” cleaning. The use of cleaning chemicals does require patience. If you do have your roof power washed, you certainly do not want to do so a second time since the damage by such cleaning will be compounded.

After you clean the roof, apply ZincShield® right away so it can go to work to insure future cleaning will not be necessary.


On what types of roofs can ZincShield® be used?

ZincShield® can be installed on the following types of roofs: Asphalt, sometimes referred to as "composite", shingled roofs.  Fiberglass shingled roofs.  Wood roofs such as cedar shake roofs.  Flat tile roofs.  Concrete roofs.

ZincShield® can be used on new or old roofs. New roof applications are great since no stain causing organisms have had a chance to get a foothold on the roof – start right away protecting your investment with ZincShield® and keep it that way. The same is true for old roofs with no existing stains - install ZincShield® as soon as possible before stains start showing up.   If you have had your roof power washed, install ZincShield® right away because you don't want to have the roof cleaned again due to the damage such cleaning causes (as well as the high cost of cleaning)!

Old roofs that are currently stained should be chemically treated prior to installation of ZincShield®. Once treated, ZincShield® will keep the roof clean.
A good product for cleaning a stained roof is Roof-Be-Clean®. For product details, see www.roofbeclean.


Are there types of roofs that ZincShield® NOT be used on?

ZincShield® will not work on barrel (Spanish) tile roofs since rainwater will not flow over the ZincShield® and down the roof in such a way to allow all surface areas of the roof to be properly protected by the released zinc ions. Our LiquidZinc® product can be used on this type of roof to keep stains away. For this type of roof, clean by power washing or use chemical cleaning to avoid power washing (www.roofbeclean).


How long will ZincShield® last?

ZincShield® is manufactured from heavy duty, copper-hardened zinc and will last up to 20 or more years under normal conditions. This is longer that the life of most composite asphalt shingled roofs.

If removed carefully, ZincShield® can be reused.


What is the correct method for installing ZincShield®?

Basically ZincShield® is installed at the top of the roof below the ridge cap, ridge vent or below the first row of shingles.  If the roof has multiple ridges, install ZincShield® at the top of each ridge. It should normally be installed on both sides of each roof ridge.  ZincShield® should also be installed below any obstruction that interferes with or blocks the normal flow of rainwater over ZincShield® and on down the roof. This includes chimneys, dormers, skylights, etc.  ZincShield® should be cut to length for each point of installation using scissors or tin snips.

Installation on an Existing Roof:
If your roof is currently stained, it should be treated prior to installation of ZincShield® with a chemical product made for this purpose. A good product to consider is Roof-Be-Clean® (see www.roofbeclean for product information). 
Using 2.5" or 3.5" wide ZincShield®, install by butting the zinc strip against the ridge vent, roof cap or the top most row of shingles at the roof ridge.  (If possible, it is best to slide about 1/8" to 1/4" under the roof ridge vent, roof cap or the top row of shingles).   Also install ZincShield® below any obstructions that block the flow of rainwater - chimneys, skylights, etc.
If our GSP-95® Adhesive is used, apply quarter to half-dollar (1-1/4" to 1-1/2") size spots of adhesive at approximately 1-foot intervals pressing the zinc strip down flat to the roof as you move along. Use a standard caulking gun for application of the adhesive. (Note: Do not apply a continuous bead of adhesive as it will block the flow of water/moisture should any rain get under the strip or if any condensation should occur under the strip). 
If nails are used, nail at approximately two-foot intervals using ZincShield® Nails with the provided rubber washers to seal the nail holes. 

Installation when Reroofing or for a New House Application:
Using the 3.5" wide ZincShield®, install so that 3/4" to 1" is under the ridge vent, roof cap or the top most row of shingles.  Also install ZincShield® below any obstructions that block the flow of rainwater - chimneys, skylights, etc.
If our GSP-95® Adhesive is used, apply quarter to half-dollar (1-1/4" to 1-1/2") size spots of adhesive at approximately 1-foot intervals pressing the zinc strip down flat to the roof as you move along. Use a standard caulking gun for application of the adhesive. (Note: Do not apply a continuous bead of adhesive as it will block the flow of water/moisture should any rain get under the strip or if any condensation should occur under the strip). 
If nails are used, nail at approximately two-foot intervals using ZincShield® Nails or good quality roofing nails but do NOT use rubber washers as the nails should be placed UNDER the ridge vent, roof cap or top most row of shingles and thus the nail heads are not exposed.

For all Roofs:
If the total distance below any strip of ZincShield® exceeds approximately 20-feet, add another strip of ZincShield® at that point (i.e., ZincShield® is effective for about 20-feet below the strip) to protect the lower area.  Using fully exposed 3.5" ZincShield® in place of the 2.5" will increase the effective distance of the ZincShield® to approximately 30-feet.

Due to the heights of roofs and the steep pitch of many roofs, working on a roof is dangerous.  We recommend that you have a professional roofer or contractor install your ZincShield®.


Should I use 2.5" or 3.5" ZincShield®?

The decision on 2.5" or 3.5" ZincShield® should be based on the following factors:

For a new roof application including reroofing an existing roof:
We suggest you use 3.5" ZincShield®
The 3.5" ZincShield® will be installed with 3/4" to 1" under the ridge vent, ridge cap or first row of shingles with the remaining 2.5" - 2.75" exposed to rain flow.  In this case, regular roofing nails are used since the nail heads will not be exposed.
An alternative installation approach is to use the method indicated below for application on an existing roof.  This is especially appropriate for roofs with a distance of over 20-feet from the ridgeline to the gutter/dripline of the roof or when 2.5" ZincShield® is used on a new roof aplication.

For an existing roof application:
Use the appropriate width for your specific roof size...
2.5" ZincShield® is effective for approximately 20-feet below the strip.
3.5" ZincShield® is effective for approximately 30-feet below the strip.
Install either the 2.5" or 3.5" ZincShield® with about 1/8" to 1/4" slid under the ridge vent or first row of shingles, etc. in order to force the flow of rainwater over the top of the ZincShield® .  Use either GSP-95® Adhesive or ZincShield® Nails for proper installation.

If you have questions, give us a call or contact us by email... we look forward to helping you!


Should I Use GSP-95® Adhesive or Nails to Install my ZincShield®?

Installation of ZincShield® with either GSP-95® Adhesive or ZincShield®  Nails is acceptable; however, there are different considerations for existing vs. new roof applications.  The following may help you decide what the best method is for your specific application.

Existing roof applications: 
When ZincShield®  is installed on an existing roof using nails, normally the nail heads will be exposed to the weather.  This is because it is usually not possible to nail under a row of shingles that have been in place for some period of time.  When the nail heads are exposed, it is necessary to use our ZincShield®  Nails WITH the supplied neoprene washers in place so that the nail holes will be sealed correctly. 
Having exposed nails can be avoided by using our GSP-95® Adhesive - therefore the use of GSP-95® Adhesive is the method we recommend for installation of ZincShield®  on an existing roof.

Reroofing or New House Application:
Normally ZincShield®  can be installed on a new roof without nail heads being exposed since a part of the ZincShield®  is nailed under a row of shingles, the ridge vent, etc.  When nails are not exposed, the neoprene washers should NOT be used so that the nails are nailed flush with the surface of the zinc strip.
ZincShield®  can also be installed with GSP-95® Adhesive for a new roof application.  The advantage of using the adhesive is that more of the zinc strip can be exposed than when nails are used.  The more ZincShield®  exposed to the weather, the better will be the protection of the roof from stains.


How much ZincShield® will be required to protect my roof?

See FAQ “What is the correct method for installing ZincShield®”.

Add the lengths of all roof ridges (both sides) plus length below all obstructions including chimneys, dormers and skylights. If a second strip is required at any 20-foot points, add the roof length at those points as well.

For example, a roof with a 40-foot long ridge would require 80-feet of ZincShield® (40-feet for each side of the ridge). If the roof has a skylight, add the width of the skylight, say 2-feet. If there are three dormers each with a width of 3-feet, add another 9-feet. Total ZincShield® required would thus be 91-feet (80+2+9) or 2-rolls of 50-feet each.


Will ZincShield® keep its shine?

No, ZincShield® will quickly weather so that the finish will have a dull, pewter-gray appearance.

ZincShield® is a much better choice than having an ugly, stained roof.


Can I paint or color ZincShield® in some way?


Any coating over ZincShield® would keep it from releasing the zinc ions that keep the roof stain free.


Will ZincShield® rust?

ZincShield® cannot rust because it is solid zinc alloy throughout - 99% zinc hardened with a trace of copper.

Some competitive products are galvanized steel. Galvanized steel is steel coated in zinc either by dipping the steel in hot melted zinc or by electroplating the steel with zinc. Regardless of the manufacturing process, galvanized steel has only a very thin coat of zinc and, after a period of time, the steel will be exposed and rusting will occur.

Installation nails can possibly leave rust stains. To avoid this, use only high quality, double dipped galvanized roofing nails with neoprene washers like the ones supplied with ZincShield®.


Can I install ZincShield® myself?

Due to the heights of roofs along with the steep pitch of many roofs, working on a roof is dangerous.

We recommend that you have a professional roofer or contractor install your ZincShield®.



Why not use chemicals instead?

While there are chemicals available to clean roofs, most of these are not designed to keep the stains from returning. 

That is why ZincShield® is so different – ZincShield® lasts for 20 years or more. Put ZincShield® on one time and forget about roof stains.


Is Special Product Pricing Offered to Contractors?

We do offer discounts to roofing contractors, roofing supply houses, hardware stores and companies that provide cleaning and related services to homeowners and businesses. If interested, contact us and we will be happy to discuss your specific business needs.

Is ZincShield® Manufactured in the USA?

YES!  ALL of our products are manufactured in the USA.  This includes ZincShield®, LiquidZinc® and our Easy Moss Scraper® .  Our nails and adhesive are also manufactured in the USA.

We also make every effort to buy only American made supplies for use in our business.

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