Zinsser Watertite Review – Waterproof Paint

I am a Decorator, and I used Zinsser Watertite for the first time a few months ago. It’s quite an extraordinary product, and so different to any paint I’ve used in the past. I thought it would be useful if I sat down and wrote a quick review. Click here to see online prices.

What is Zinsser Watertite and What is it Used for?

Zinsser Watertite is an oil-based paint product used to stop water from penetrating a surface. It holds back up to 34 psi of water pressure.  It is mostly used in basements and cellars; however it can also be used on outside walls to protect them from the elements, and even concrete slabs prior to installing a floor.

This paint comes in white and is a two-coat system, however you can paint over it with any paint you like. Watertite can be applied to concrete, stucco, cement, brick, cinder block and other masonry surfaces.

Zinsser Watertite is touch dry after an hour, the recoat time is 4 hours, and it’s fully cured after around a week, however drying times vary depending on conditions. You should use a brush to apply the first coat, and then brush and roller to apply the second (I’ll go into more detail further down the review).

My Zinsser Watertite Review

OK, my personal thoughts. I use a lot of Zinsser products and they do solve a lot of problems. But a paint that you can apply to a wet wall and holds up to 34 psi of water pressure? That’s the tyre pressure of my work van!! It sounds a bit too good to be true.

Well, Zinsser Watertite does work. I painted a basement with it about 8 months ago. The walls were damp to begin with, and the room always suffered with both mould and efflorescence prior to decorating. My client wanted to start using the room to store household items, but thought he needed to get it tanked until I suggested Zinsser Watertite.

The paint adhered brilliantly, and the problems with damp, mould and efflorescence completely disappeared! Until I did this job, I wouldn’t have believed any paint product would have been capable of so much! I’ve always been taught that surfaces need to be clean and dry before you can even think about painting. 8 months on, and the job still looks mint!

Applying Zinsser Watertite is very slow going, and the paint doesn’t spread very far, so you will need quite a lot of paint to double coat a small room. However, the opacity is spot on (you’ll never need more than two coats), and it is very low odour. So, allow extra paint and extra time for your decorating. Click here to see online prices.

How to Apply Zinsser Watertite

Applying Zinsser Watertite can be a bit slow going and tricky, so I thought I’d include a section on how you should do it.

Ventilate the Room When Working Inside

The first thing you need to do is make sure the space you’re working in is well ventilated. Zinsser Watertite may be low odour, but it’s still oil-based and you may well need to use strong cleaning agents before applying the paint.

Clean

Clean any mould or mildew from your surfaces with a good fungicidal spray. Clean contaminants with sugar soap or Zinsser Degreaser (click here to see prices). Once you’ve cleaned, remove any loose material that may otherwise cause adhesion issues.

Remove Existing Paint

Zinsser Watertite can be applied over a previous paint coating, but the previous coating will become the weak link between substrate and Watertite, so it won’t be effective up to 34 psi of water pressure unless you can remove it.

Repair Holes and Cracks

Then fill any holes with a good cement-based masonry filler and allow to fully cure. My recommendation is Zinsser Rock Sold Filler, simply because it’s easy to use, won’t hold onto water, and will withstand adverse conditions. Repairs made using Toupret Rock Solid Filler will last forever. Click here to see online prices.

Apply the First Coat

Once the prep is out of the way, you’re ready to apply the Zinsser Watertite. Never dilute it! Instead, decant into a paint kettle and apply with a 3-inch synthetic paintbrush with a thick stock (click here to see online prices).

You need to really work Zinsser Watertite into every pinhole, otherwise it won’t be waterproof. It’s thick and sticky, so it is hard going, but take your time and stick with it. Some people apply the Watertite using a 9-inch-long pile roller to an area of 1 metre square at a time, and then work the paint into any pinholes with a brush. A Purdy Colossus paint roller is perfect for this (click here to see online prices).

Apply the Second Coat

Once the first coat is dry, the second coat goes on a lot easier. It’s still thick and sticky, but you’ve already filled the pinholes, so it’s just a case of applying the paint. You can cut in with a paintbrush and then roll off like you would any other paint.

Review Summary

Final Thoughts

There you have my Zinsser Watertite review; it may be slow to apply, but it really is a great product. I honestly can’t think of any other paint product that can keep water out of a room, will stop all future mould growth, and stop efflorescence. Unbelievable really.