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Vinyl Liners Mil vs. Gauge Thickness

Why do some vinyl liner manufacturers use mil and some use gauge to specify the thickness of their liners?

A mil is a specific set measurement that can beDigital Micrometer measured with a micrometer. One mil is equal to an exact .001 of an inch. A 20 mil liner is .020 of an inch thick. A 28 mil liner is a little thicker at .028 of an inch thick.

A gauge is not an exact measurement when it comes to pool liner thickness. Most pool liner manufacturers use it for above ground pool liners to indicate a measurement that is close to but not an exact .001 of an inch. Some online retailers may actually list a liner as Mil when the manufacturer list it as GA. Others may list a high number for their liner such as 45 GA. In that case you would need to find out what thickness their gauge is to dermine how thick the liner is. There is no set thickness for 1 gauge. It will vary for differant manufacturers.

Most people assume that a thicker liner is better. A 27 mil or 28 mil liner will give you better UV protection and a little better protection from a rough pool bottom. However, the most important factor for a liner to last the longest is how well the liner fits and the pool water chemistry. Any thickness over 28 mil does not have any benefits for most pools. 

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  1. Wes Crabiel says:

    Is there a preferred Mil for in ground pools when factoring in a tough winter (Cleveland)?

    Some say a 20 mil has more “give” to it than a 27 mil – your thoughts please.

  2. Dave says:

    Most manufactures sell liner thickness with two choices. There is the mil choice and the gauge choice. The fact is that these terms are interchangeable and mean the same thing in the pool industry. So when you have the choice of a 20 mil it’s the same as a 20 gauge. This 20 mil or 20 gauges represents the standard thickness of above ground pool liners on the markets today. Having a 25 mil or 25 gauge liner is of course thicker and will carry a better warranty and generally last longer. All liners are subject to punctures and tears from outside elements.

  3. Gauge manufacturer says:

    I just want to thank you for sharing your information and your website, this is simple, but good article I have ever seen, I like it, I learned something today! Thanks!

  4. Philip says:

    I was told that a 20 mil liner is better then a 27 mil liner for new Jersey to avoid damage from ice in the winter. Is this true for cold climates like NJ. thanks….Phil

  5. Foster says:

    I believe what they were saying is that a 20mil liner has more flexibility and is less likely to tear with expansion. Typically the only time I would recommend going thicker than 20 mil is if you have an abrasive surface of some kind.

  6. mike says:

    My wife and I live in so. AZ. have a 25gage 15×30,52″ oval, my liner split a 2″x10″ tare in it just above the waterline.I take every precatuion to make sure my cem’s are on the money.Temps here hit 102 easy in summer,as for winter i go by the book for shutdown,i’ve crossed my T’s doted my I’s,have my chems cheched twice a week when i’m in town to double check my findings.My wife and i were thinking of going to a 28mil or 30mil liner. THIS JUNK OF A LINER ONLY LASTED US 1YR-8MONTHS SO WRONG!

  7. Greg says:

    Hey Mike, sometimes just having a good chemical balance isn’t enough. If the liner is too tight or if the sand deteriorates from underneath the liner causing the liner to stretch more than normal, these factors can also cause a liner to fail prematurely.

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