Flex Seal review: Flex Shot, Flex Glue, Flex Tape, Flex Liquid

In this review you will find information about Flex Seal products – they will help those who need to repair a leak in the roof, pool, barrel or any other object or surface. So, your roof leaks all the time and you are dreaming to fix it once and for all? I think you need a high quality and reliable material, that is easy to apply, safe and that will serve for a long time. I’m sure that Flex Seal is exactly what you need.

For quite a long time builders were missing this perfect material, that will ensure reliable damp proofing. All rolled materials used earlier (such as roof felt) were put end-to-end, therefore all slits were then sealed separately. However, time compromises the integrity of sealing.

The cover loses firm adhesion with the base and exfoliates, joints dissolve and water ingresses inside. Nowadays, liquid rubber appeared and Flex Seal is one of the options you may choose.

Flex Seal

What Flex Seal is look like?

The material has appearance similar to rubber: it is black, white or gray, waterproof and it has high elasticity. Before you apply it, it looks like emulsion.

Flex Seal belongs to a group of two component pastes. Manufacturers don’t really like this simple term “liquid rubber”, they prefer to call this type of sealing material a “solid-drawn spray-applied hydroseal”. Though, for users convenience they agree for calling it “liquid rubber”.

The thing is that liquid rubber composition is different from those of an ordinary one. It is based on using emulsified bitumen with addition of polymers and stabilizers.

Features of liquid rubber

Its main difference from its analogues is that it freezes instantly and transfers into solid phase right away. The watery base of the material prevents toxic substances formation and their evaporation.

Flex Seal is becoming more common in the Northern regions, since it can stand abrupt subzero weather. Besides, this material is free from the main demerit that bitumen has – aging effect.
Carboxethyl ester that bitumen contains evaporates gradually. Presence of polymers in liquid rubber prevents aging and extends its service life up to 20 years.

Flex Seal Liquid Rubber

Flex Seal – is very firm and elastic material. It doesn’t exfoliate at vibration, mechanic damages, rapid change of temperatures and etc. Its composition isn’t flammable, sturdy against chemicals and basic construction mixes.

When is liquid rubber used?

Its main application area is all kinds of waterproofing work. Besides, it is applied in the following cases:

in civil engineering – to improve vapor-proof barrier and waterproofing layer of partition walls, floors, basements, storage basins and capacities, external surfaces of walls under the conditions of increased humidity;

when building hazardous industrial facility – subways, tunnels, bridges, to strengthen slopes and embankments, subsurface rock;

for tubes, basements, walls, basements, floors waterproofing, when reconstructing an old or building a new roof;

in agriculture – when damming and building channels for irrigation;

when developing waterworks and in civil engineering – to ensure water-resisting properties of water towers, bunkers, pools, sediment basins, drains and to protect concrete constructions.

What are Flex Seal advantages?

In comparison with traditional sealing materials Flex Seal has the following advantages:

  • when applying on a surface it covers it with a solid cover;
  • spraying is performed by means of “cold spraying” (i.e. neither the surface, nor the substance require heating);
  • it has long lifetime;
  • waterproofing layer made of liquid rubber is resistant to temperature gradients from -45°C to 100°C;
  • it sticks well to any construction materials;
  • roofs become completely waterproof, this type of hydro isolation has no joints;
  • this material is resistant to ultraviolet, chemicals influence and mechanic damage;
  • it is quite economizing when applying it on a surface – it doesn’t require water, fire or electricity;
  • odor free;
  • high elasticity, easy to stretch and recovers its original shape fast;
  • rust proof and ecologically harmless material;
  • it can be applied on any surfaces – horizontal, vertical, inclined ones.

When you shouldn’t apply Flex Seal

Flex Seal Spray

If you have big plans to reconstruct and repair your roof, maybe it’s worth to reconsider the idea of buying this material. As well as it is quite costly, the material can be removed only manually, which will take rather long, since Flex Seal almost doesn’t react with petroleum products and solvents.

How many flex products are there?

The company has designed several types of materials:

  • Flex Seal Spray – spray. This is the best way of quality and fast sputtering of liquid rubber on large areas;
  • Flex Seal Liquid Rubber – it is prepared right before you start the work and then you just apply it on the surface. This type of liquid rubber looks like paste or thick creamy liquid, which is manually applied on a surface you’d like to protect from water. Paint scrapers, brushes and paintbrushes are used for this.
  • Flex Tape Rubberized Waterproof Tape – is a specialized tape, that you can turn over the leaking spots or you can close the hole with it. The tape is very sticky and firm.
  • Flex Glue – as you see from the name, this is a glue, it is manufactured in a tube like the one in which silicone is sold. However, unlike silicone you can apply Flex Glue even under water.
  • Flex Shot – is a multipurpose sealant. Flex Shot is a perfect alternative to a bulky caulk gun. Its small sized handy packing allows efficiently and sparingly rectify leaks, fill holes and cracks, caulk a joint etc. This sealant can be applied to almost any material and it dries quickly.

So, if you need to process a small area, for example, to seal a chink in a balcony on the 2nd floor, now there is no need to call some specialists with bulky inventory. You can use Flex Seal Spray or Liquid Rubber.

At that, you still have to understand that to perform some more serious and large scaled tasks on damp proofing of your roof, you’ll still have to call specialists.

How to apply Flex Seal properly?

Whatever type of liquid rubber you buy, it’ll by all means firmly stick to any surface whether it is a metal, wood, concrete, brick or resin one. The only requirement is that this surface is dry and dust-free if possible.

Flex Glue

To prevent moisture ingress the liquid rubber is applied with plenty to spare. For instance, when sealing a chink in a balcony, you should also process a part of the neighboring wall. The height of overlap is about 10 inches. At the same time you should process all joints within reach.

Thickness of the layer you should apply depends on a surface you are processing with liquid rubber. Therefore, on a metal roof you should apply a layer at least 2-3 mm thick, on brickworks – up to 1.5mm and for concrete structural sections – up to 2 mm.

When spraying liquid rubber on a roof, you should wash the surface thoroughly, dry it and clean off the grease from it. Before you start applying waterproof layer you should do the following:

  • make sure that the roof is reliably and properly fixed;
  • prepare the roof surface for the substance application;
  • prepare necessary equipment and tools;
  • get Flex Seal in the required amount

In general, you can use this material at almost any temperature above zero. If you spray it at temperature 50 °F (10°C), it’ll solidify completely in a day, at 100 °F (20°C) the term of solidifying decreases up to 4 hours. The main thing is that the weather stays dry during this period of time.

Flex Tape

Flex Seal is a high quality modern material that is being regularly used all over the world. Due to its unique properties Flex Seal is widely applied when building large industrial objects. However, any owner of a small house can use Flex Seal as well to perform running repairs.

Flex Seal products review

Flex Spray review – for fast repairs

This is a spray for fast application and surface processing. Keep in mind that the material contains volatile substances and is not as safe as other products you can choose. Therefore, it’s not recommended to use the substance inside or to process places where there are pets as well as pools and ponds.

Take into account that this product is the least efficient one and to get the effect you’ll need to apply it in several layers and dry it properly. This material has rather wide color array in comparison with Flex Seal Liquid Rubber.

Flex Spray Faq’s

How to apply Flex Seal spray?
The process is identical to the one of Flex Seal liquid application described above.

How long does Flex Seal spray take to dry?
Since Flex Spray is an aerosol, it contains volatile agents and its primary drying out lasts less than an hour. Time of complete drying out depends on the thickness of applied layer and the temperature, but at that it doesn’t exceed 24 hours.

Can Flex Seal liquid be painted over?
Yes, but you can apply only Flex Seal Liquid Rubber this way. This is a liquid rubber in a bottle, you can apply it to any surface by means of a brush and create a protective coating for it.

Flex Seal Liquid Rubber – you should have it in every house

This is the continuation of the company product line – the most reliable and convenient one. This is the product you can use to seal some serious leakages. Roofs, pools, cars, boats, basements – the list is endless. Large volume allows not to economize and to waterproof any surface.

Unlike the spray Flex Seal Liquid Rubber is not toxic and can be used at any conditions. It is easy to work with, you can clean the tools after work by means of solvent.

Flex Seal Liquid Faq’s

Does Flex Seal work?
Of course, Flex Seal is a popular drip-drying silicone caulk sealant that can be used almost on any surfaces. Its composition provides reliable coating, UV protection and anti-corrosion coating.

Purchasing Flex Seal liquid rubber will be useful not just for those who are in the middle of repair works. This glue is good for mending boats, cars, sports equipment, water pipes, roofs etc. This is a multipurpose assistant you can utilize during repair and reconstruction works of any complexity.

How to apply Flex Seal liquid?
Before applying Flex Seal glue it’s recommended to clean the surface to be processed from rust marks, dirt and remove moisture from it. Depending on the material type additional degreasing of the surfaces may be required. The process of Flex Seal applying is extremely simple and it consists of the following steps:

  1. Prepare workware and shoes. Use gloves to protect your hands. Flex Seal isn’t toxic for your skin, but it may cause skin irritation.
  2. Cleaning the surfaces. The cleaning approach depends on the surface material: wood is filed away and covered with preservative substance, metal is cleaned and degreased, concrete is processed with a special primer or some hardening treatment is applied. You can skip this stage, but in this case the adhesion will be poorer.
  3. This substance can be used on solid glossy finish surfaces covered with oil paint. You should wipe them with soda solution in advance.
  4. When preconditioning process is over you should wait till the surface dries.
  5. The first layer of the sealant is applied with a roller or a brush. It dries fast enough, but to obtain secure retantion you should wait at least for 2 hours. Then you can apply the second layer using the same approach.
  6. While applying the sealant make sure that all cracks and holes get filled with it. If you didn’t manage to do this from the 1st try, you can apply the 2nd layer after partial drying out of the first one
  7. Wash the instruments when you finish the work. The processed surface requires no additional processing.

What surface area can be covered with one bottle of Flex Seal?
As you see it highly depends on the layer thickness and the surface material to which you apply the sealer. You can find the approximate values in the table below:

16 ozup to 20 Sq. Ft
32 ozup to 40 Sq. Ft
1 galup to 150 Sq. Ft

Can Flex Seal be used on fabric?
Flex Seal liquid and Spay can be applied to any surface – fabric, metal, glass, cleaving stone, Dutch tile, brick, wood.

Does flex work on wood?
Surely. Besides, wood demonstrates high adhesion with Flex Seal composition.

Does Flex Seal provide uv and chemical resistance?
Yes, as well it does provide resistance to other negative impacts.

How long does Flex Seal last?
Minimal useful life you can expect from this coating is several years. During this period of time Flex Seal doesn’t lose its properties and doesn’t crack. However, as a rule this period lasts longer. It depends on the environmental conditions and loads that Flex Seal coating is exposed to.

How long does it take Flex Seal to dry?
Primary solidification occurs in 2-3 hours; Flex Seal gets completely dry in 24-48 hours. This time may vary both upward or downward. It depends on air temperature, humidity level, sealant layer thickness and other factors. If when pressing the sealant layer you feel that it is soft or sticky, it means that it hasn’t dried yet.

Is Flex Seal oil resistant?
Yes. It can be used on oil and oil tanks.

Is Flex Seal flammable?
Flex Seal is non-flammable and safe product.

Is Flex Seal toxic?
Flex Seal is biologically and physiologically inert substance, which means that it doesn’t react with living organisms. Flex Seal is safe for animals. It can be successfully applied even in pools with fish in them.

At that this sealant doesn’t provide any nutritional medium for bacteria and when it dries it preserves this feature as well.

Can Flex Seal tape be removed?
Yes, by means of solvent removers – acetone or White Spirit.

How to remove Flex Seal from metal?
With the help of acetone and a cloth. But you should act fast, because if Flex Seal gets dry, using just acetone won’t do. You will have to wet out one layer after another using acetone and cut it off by means of a knife or palette-knife.

Attention! One of the hazards when working with acetone is its flammability. Its air mixtures that contain from 2,5 % to 12,8 % (in volume) are highly explosive. You should keep this in mind, since acetone evaporates rather quickly and the cloud that forms after this can travel to the inflammation spot (where it catches a flake of fire of gets heated) far from the place where acetone was actually used.

How to remove Flex Seal from car paint?
By means of methylbenzene, since acetone or White Spirit may also remove paint layer as well or change its color essentially. Toluene is less deleterious substance.

Moisten a piece of cotton wool with toluene and put it on a Flex Seal stain. Wait for a minute. Try to remove Flex Seal carefully with a soft cloth. Repeat the process until you remove the stain completely.

Attention! Toluene vapors can penetrate through uninjured skin and respiration organs and cause nervous system disorders (dormancy, vestibular apparatus disorders) some of them can be irreversible. That’s why you should wear solid rubber gloves when using toluene and other solvent removers that contain this substance as well as use it in properly ventilated room with drawing ventilation.

How to remove Flex Seal from concrete or brick?
The answer here is the same as above – use solvent removers. However, Flex Seal has better adhesion with concrete and bricks and it won’t be that easy to remove it. In this case we’d advise to consider mechanical ways of removing Flex seal.

How long does Flex Seal smell?
Flex Seal smells the strongest for the first 2-3 hours till its upper layer gets dry. Flex Seal dries completely within 24 hours (at standard temperature and humidity parameters). The smell may persist for the same period of time.

What is Flex Tape made of?
The formula is patented and the manufacturer keeps it confidential.

Does Flex Seal come in colors?
Currently there are four colors available – Black, White, Clear and Gray.

Is Flex Seal waterproof?
Yes, the main task of the product is water and rust protection.

Сan you apply Flex Seal to wet surface?
Yes, despite the fact that it will stick better to dry and degreased surfaces, it can be successfully applied to wet and even soaked surfaces.

Can i paint over Flex Seal liquid?
Yes. In 24 hours after application of the sealant you can use latex paint and in a week you can apply oil based paint.

Can Flex Seal be used on hot surfaces?
Yes, Flex Seal is heat resistant and it can be used on roofs and in premises with high temperatures (the range can vary from 80 to 350 degrees). But it is best applied between 32 degrees and 120 degrees.

Does Flex Seal require any dilution?
No, the substance is completely ready for application and doesn’t require dilution.

How to get Flex Seal off hands?
If you need to remove Flex Seal from skin, you can try several ways given below.

Way 1
You will need a plastic bag and soap. Instructions are the following: take the plastic bag. Rub your hands with it – silicone has to stick to the bag. Wash you hands thoroughly with soap under running cold water. Repeat the procedure till Flex Seal is completely removed from your hands.

Way 2

If the stain is fresh, put you hands into a saucepan with warm water (it shouldn’t be too hot!). Hold them there for a few minutes. Soap the hands and rub them with harsh stone. Then wash your hands under running cold water.

Way 3
Try to clean your hands from the sealant by means of solvent removers – acetone or nail polish remover. If you have any of these at hand, follow this sequence of operations: pour the substance you have on a cotton pad. Process all the stains with it. Take a piece of soap. For several minutes thoroughly wash your hands under running cold water.

Way 4
One of the most efficient ways to solve the problem of sealant stains on your hands is a vinegar solution. It can remove even dry sealant stains. Follow these instructions to apply it properly: make the vinegar solution by mixing it with water in proportion 1:1. Wash your hands in it. After you remove the sealant stains from your skin wash your hands with soap under the running cold water.

Once you’ve successfully removed Flex Seal stains from your hands apply some moistening cream to restore the skin and reduce the chances of any allergic responses.

Flex Tape review – its a firm tape, but don’t expect any miracles here

Commercials say that this tape will stop the leakage, work under water and solve whatever problems you have with waterproofing. Unfortunately, this isn’t so. You should understand that if there is a hole in a water pipe and the pressured water is running, not even the highest quality patch will stop it completely.

However, Flex Tape is good as a temporary solution till you find another one. It’ll stop the main rush of water, though it won’t be able to turn the water off.

However, if you need to fix the leakage from inside, then Flex Tape is exactly what you need. In this case the water pressure helps the patch to stick to the wall. In general, this is a good product, but don’t expect it to do miracles.

It will do as a patch for a hole in the pipe, it’ll stop the water at low pressure, serve as a temporary patch, but it won’t stop the water at a high pressure.

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Flex Tape Faq’s

How long does Flex Tape last?
The manufacturer doesn’t provide us with this information, but according to user reviews it lasts about 3 and more years.

Can Flex Tape be removed?
Of course, though it’s not that easy. The manufacturing company produces a special product for this – Flex Tape Adhesive Remover. However, it is sold only on-line on the company’s site and you’ll have to wait till it is delivered. Therefore the next question arises.

How to remove Flex Tape?
If you don’t have Flex Tape Adhesive Remover at hand, you can do it using materials at hand. Be ready that it’ll take some time. You will need a kitchen degreaser and a sharp knife. You moister the tape, wait for several minutes and then cut off the tape layer.

Can I apply Flex Tape to air mattress?
No, the manufacturer doesn’t recommend to do so. Your life may depend on this kind of patch.

Can I use Flex Tape to patch the hole in a tire?
No, it’s not recommended to use Flex Tape neither for bike tires, no for auto tires. Guard your health and life!

Can I apply Flex Tape to fiber?
Yes, but it doesn’t stick good to some kinds of fibers. If it happens, you’d better use Flex Seal Spray, let it dry and then apply Flex Tape. You can speed up the glueing process if you heat Flex Tape with a fan.

Can I cut Flex Tape?
Yes. Use sharp scissors for this purpose.

Can Flex Tape be used on hot surfaces?
Yes, but the temperature shouldn’t exceed 200° F. At temperature higher than 200° F the substance loses its hardness and becomes sticky and therefore Flex Tape may loose its properties. It is recommended to use Flex Tape at temperature range from 20° F to 120° F.

What sizes are on sale?

  • 4 inches wide by 5 feet long
  • 8 inches wide by 5 feet long
  • 12 inches wide by 10 feet long

What are Flex Tape colors?
Black and white.

Can I paint Flex Tape?
Yes, but most of paints don’t stick to it. In this case you can use Flex Seal Spray as a primer and then apply the paint.

Flex Glue – an expensive product, but quite an ordinary one

The ads promise that this material will immediately stick on any surfaces and will work for a long time. However, this is just what the ads say. In fact, the glue is of rather middling quality.

It dries for a long while and its durability is so so. I wouldn’t recommend it, since the products mentioned above are of several times higher quality.
This one doesn’t differ from any cheap glue at the hardware store. Except its cost!

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  • Flex Seal for moistureproofing can reliably stick on almost any surface
  • The quality of obtained adherence doesn’t depend on “how old” the surfaces are
  • It gets inside chinks and defects of all forms by following the defect shape and filling it sealably. This is what makes it different from other sealing materials, which have higher consistence
  • It excellently protects the surfaces from rust, since it works without any joints
  • High elasticity ensures the liquid rubber durability without cracks and deformations
  • Waterproofing performed by means of liquid rubber is absolutely not toxic. Even at hot weather this covering doesn’t evaporate any volatile oils.
  • It is possible to waterproof a basement in the block of flats by means of liquid rubber without temporary expulsion
  • When spraying the material it fills any chinks and cracks even the smallest ones – the whole processed surface is uniformly filled with hydrobonder
  • This material is easy to repair – in case of mechanic or any other damage you should just apply some more Flex Seal where needed and the whole construction is protected from water again.
  • Flex Seal Spray has a wide color palette, which allows using it when creating design elements


  • Quite an expensive thing. Though it pays off with some advantages and long lifetime
  • However, in case of inappropriate usage the material is not durable