Most PVA glues used for construction and carpentry are Type II water-resistant.
Even though they are water-resistant to grade 2 and can sustain several cycles of soaking and drying without having the glue fail, you still can’t waterproof surfaces with PVA.
While some PVA glues are made to be waterproof, they’re still not enough to waterproof various materials.
Is PVA Glue Waterproof When Dry?
Industrially-used PVA glues are water-resistant to grade 2.
This means that it can sustain several cycles of soaking and drying without having the glue fail.
However, this does not make them waterproof.
However, Type I waterproof PVA glue can be waterproof when dry, allowing surfaces it covers to completely repel and resist water damage.
But make sure you get the Type I PVA glue.
Otherwise, it won’t hold up with water.
How To Make PVA Glue Waterproof
Unfortunately, the typical PVA glues used in industrial settings are not waterproof, and there’s no way to make them waterproof.
If you want to use waterproof glue, look for a PVA glue that is specifically made to be waterproof, like Type 1 PVA glues.
It’s easy to find if the PVA glue you bought is waterproof.
All you have to do is check the label of the tube, bottle, or can and see if it says waterproof.
In the future, make sure to read the instructions of whatever glue you want to purchase to ensure that you’re buying something waterproof and not just water-resistant.
This will be easy as the law dictates that all adhesives, whatever they’re used for, should mention in their packaging if they are made to be waterproof or not.
Is There A Difference Between PVA & Waterproof PVA?
Yes, there is a difference between PVA and waterproof PVA glue.
In fact, there are three types of PVA glues that you should know about: Type I PVA glue, Type II PVA glue, and Type III PVA glue. Here are their difference:
Type I PVA glues are generally waterproof.
This type of PVA glue is used in Titebond II, which contains water in the formula, but can resist water erosion and separation.
This is why it’s a good choice for exterior applications.
Type I waterproof PVA glue has polymer strands that become entangled during the bonding process.
This makes Type I PVA glue perfect for outside or exterior wood trim, wood fasteners, birdhouses, mailboxes, plastic pools, and outdoor furniture.
This type of glue repels and resists water damage.
Another type of PVA glue is Type II water-resistant glue.
This type of PVA glue is usually used in Titebond II.
It also contains water in the formula, resisting some water erosion and separation.
In addition, it contains a similar polymer formula as Type I glue. However, it does not have any of the complete waterproof capability of the Type I PVA glue.
The formula used in Type II glue has medium water-repellent qualities, which falls in between the non-waterproof and full-waterproof categories.
While type Type II PVA glue can also work well with exterior trim and joints, it can’t come in prolonged contact with water since it will eventually break down.
The last type of PVA glue is Type III glue.
Unfortunately, this type of PVA glue does not have water-resistant qualities.
The most popular Type II PVA glue comes from Elmer’s.
This glue contains nearly 50 percent water, which makes cleaning up easy.
However, glued surfaces should be clamped until they achieve 15 to 20 percent of their bonding strength.
To achieve a secure bond, you should cure the surface for at least an hour and 24 hours if you need a full-strength adhesion.
Type II glue also bounds efficiently with porous materials.
Can You Waterproof MDF With PVA?
No, you can’t waterproof MDF with PVA glue.
However, you can seal MDF surfaces with thin layers of PVA–white or carpenter’s glue.
If you want to waterproof MDF, you can use an enamel primer.
But make sure you only apply thin coats and do not build up layers. Building up layers will run or drip as the enamel dries.
In addition, only oil-based or lacquer-based enamel primers are waterproof.
At the same time, it only works on some surfaces, such as uncoated MDF, without preparation.
Can You Waterproof Wood With PVA?
In some cases, yes, you can waterproof timber with PVA.
However, it’s not as solid and reliable as other glue.
For example, PVA glue can be added to a cement mortar mix which can give the mix slightly better waterproofing qualities and advanced adhesion to the surface it is applied to.
When wood is sealed with PVA, it can provide some waterproof quality.
But if the surface of the wood is to be subjected to any wear or traffic, then the PVA glue, as it is an emulsion, will eventually fail.
Sealing a wooden surface with PVA glue slows down moisture absorption and allows the surface to remain workable for a while.
However, it doesn’t guarantee that it will be forever waterproof, so be careful when using PVA glue to waterproof wood surfaces.
Can You Waterproof Fabric With PVA Glue?
Surprisingly, PVA glue can be used to waterproof fabrics.
Basically, you just need to coat the fabric with PVA glue, and it will become waterproof.
But make sure you purchase a PVA glue created for exterior purposes and not those for internal purposes to waterproof the fabric.
How To Use PVA Glue For Waterproofing
Note: PVA glue can waterproof some surfaces only and doesn’t have much effect on some materials.
- Dilute 1 part of PVA glue and four parts of water. Mix well.
- Then, using a brush, apply it to the working material well into the crevices, gaps, and surfaces you want to waterproof.
- Wait for it to dry.
Most PVA glues are water-resistant and can’t be used to waterproof some surfaces.
However, some waterproof PVA glues can be applied to surfaces.
If you need to waterproof something, make sure that you buy the waterproof type of PVA glue to avoid any problem.