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Avoid Making A Costly Mistake
Or maybe you’re just here because you love reading my tiling stuff (if you are, I appreciate you <3)
Whatever the case, this buyer’s guide is here to educate you on everything you need to know about the magical world of Tile Primers and why you need them! You will also learn about the best tile primer for every substrate.
Hello and welcome to another Tilersplace article!
Today we’ll be diving into a commonly overlooked element of DIY tiling, Tile Primers! Also known as tile adhesive primers or tiling primers.
My name is Carl Anders and I’ve been doing this tiling thing as a profession for just over 25 years. I’d like to pass on my experience so that your next tiling job lasts for ever!
Tile Primers Introduction – The Downplayed King
The vital role they play in a successful tile installation is often overlooked by their simplicity to use. Just get a broom or paint roller and slap it onto your substrate. Done.
Surely, something that is so easy to apply can’t be that important right?…WRONG!
Think about the humble tub of margarine. It’s cheap, spreads on easy with a knife and it isn’t very exciting. But you wouldn’t imagine making a sandwich without it right?
Otherwise, your peaceful lunch turns into a handful, with all the tomato and meat sliding around like kiddies on a slip n’ slide. None of us need that in our lives.
So remember, just because something is insignificant or easy to use, doesn’t mean it isn’t important.
How does a tile installation fail?
The thinset that was applied to glue down the tiles, has been applied over a dirty surface and instead of adhering to the substrate, it adhered to the dust and oils sitting on top of it.
Once traffic starts walking over it, those stresses start moving the tiles and eventually they pop off the floor and get loose.
Another reason that a tile installation can fail from lack of a primer is from the thinset not curing properly.
Tile thinset is a cementitious based compound, and like any cement based product, it requires water to set properly. If there is a lack of water, then it’s full strength will never be realised and it also won’t stick properly to it’s substrate.
When a thinset is applied over an unsealed substrate like concrete or fibreboard/cement board, that substrate will suck up the water from the thinset during the curing time.
This results in lack of adhesion and strength in the thinset, this ultimately leads to a compromised tile installation that will never last as long as it should. Think one year instead of 10+ years.
I hope that know you understand why tile primers are so important and why they should always be used! With that, let’s learn more about these amazing products so that you can purchase the right one for your tiling project.
Tile Primers – What Is It?
It can be applied with a broom, paint brush or roller – depending on the type.
The primary role of a tile primer is to create better adhesion of a thinset, mud bed or self leveling underlayment (SLU) to the substrate (the surface you’ll be tiling).
A latex tile primer can also be mixed in thinset to enhance it’s bond strength, water-resistance and bond-strength. The added properties vary from product to product.
• eliminating dust and other surface containments
• stopping the substrate from absorbing all the water in thinset, self leveling underlayment’s etc (hence allowing a proper and strong cure.)
• adding grit or texture to a smooth surface to allow a strong bond.
A tile primer is also used before applying topical waterproofing compounds and helps the waterproofing to fuse effectively to the substrate.
Without a primer, a layer of waterproofing can be peeled off with your fingers once it is dry as it hasn’t adhered properly.
In essence, a primer is the first step in a tile installation.
A Tile Primer Is NOT Tile Paint
On your journey to learn more about primers, your search engine may have shown you results talking about tile paint. Please don’t get tile paint confused with tile primer as they are two completely different things.
What Is Tile Paint? Tile paint is a specialist paint that is designed to be applied directly over tiles to transform an expensive and luxury product into a flat, monotone colored surface.
Tile paint is often seen as the quickest and cheapest way of refreshing an old tile installation but it’s mostly a method of delaying the inevitable – removing the tiles properly and retiling with a new tile.
Tile paint is not hard wearing, especially on floors and will wear out unevenly, creating a undesired look that will require a reapplication of the paint.
The tile primers discussed in this article are not designed to be used before tile paint is applied.
When Can I Use A Tiling Primer?
A tile primer should be used after the substrate has been deemed ready for tiling. This is generally after you have ripped up the carpet or installed the dry wall, etc. Then once the dust and general debris of building has been cleaned up, the best tile primer for your task can be used.
You can apply a tile primer onto floors or even walls. (If they are lined with a cement sheet like Hardiebacker.) To apply tile primer to walls, a little foam roller works best as it applies a neat coating without making a mess.
A tile primer generally only needs to be applied once on the substrate if you’ll be tiling straight onto the substrate or waterproofing it.
If you will be applying a self leveling underlayment, it’s recommended to apply a coat of primer before pouring the compound and another coat of primer on top of the dried levelling underlayment before tiling or waterproofing. This is because self leveling underlayment is cementitious and can absorb water just like a substrate. This can lead to improper curing of your thinset and waterproofing.
How To Use a Tile Primer
No matter which tiling primer you use, the aim is the same : the achieve a uniform coat of primer on the whole entire substrate that you are wishing to tile over.
If you splash the primer onto any surface that you won’t be tiling, then wash it off immediately with clean water. Wash your tools with clean water after applying the primer to avoid the product drying onto them.
How To Prepare A surface For A Tile Primer
While every manufacturer has their own instructions on how to use their product, there are a few steps that apply to every product.
2. Thoroughly sweep up or vacuum the area you’ll be priming to ensure that the primer doesn’t stick to dust. This will affect the final result.
3. If there are patches of oil residue, paint, oil, varnishes or any finish that can stop the primer from absorbing into the substrate, be sure to remove it before. This can be done with mechanic scarring like a grinder or sandpaper.
6. Avoid pooling and any high spots.
7. Wait the specified time on the primer packaging before carrying on with the next step in your tiling project.
Tile Primer Use Cases
Tile on Tile Primer
A very popular use of a resin tiling primer is to lay tiles over the top of old tiles. This is generally done when you want to spruce up or add a modern look to a tiled room. Bathrooms are very commonly tiled over.
The tile primer will be painted over the top of the tiles and grout, and provide the thinset with a sticky and rough surface to adhere to.
Self Leveling Underlayments/Compounds
A common question I find is : Do I need primer for self leveling compound?
Yes, a primer is a requirement when using a self leveling compound or underlayment. Every system comes reccomended with a tile primer that needs to be applied to the substrate before it is poured. By using a primer, you remove any contanaments and seal off the substrate from absorbing the water inside the self leveling underlayment. This ensures a proper bond and a strong cure, ready to be tiled over.
Best Tile Primers
One tiling primer is basic acrylic based milky liquid and used on porous surfaces like concrete or fibre board. The other thicker type of primer is resin based and works on non-absorbent smooth surfaces like existing tiles.
I have selected a range of primers that should cover most of your use cases, just select the primer that sounds like it’s right for you.
Generally, the more expensive primers have better performance so if you’re not sure, just buy the expensive and thicker primer and rest assured it’ll work.
MAPEI ECO-PRIM GRIP – Overall Best Primer + Best Tile On Tile Primer
The Big-Daddy of Tile Adhesive Primers, Mapei Eco-Prime Grip is a synthetic resin-based primer that works on the most difficult of situations.
This thick boi should be your choice when failure is not an option. It can adhere to all porous and fibrous surfaces and also highly smooth surfaces like vinyl and existing tiles.
It will create a sticky and suitable surface for all tile adhesives and self leveling underlayments to adhere to after it has dried properly.
Only one coat of this primer is necessary and it can be used both indoors and outdoors.
How To Apply:
Mapei Eco Prime should be applied with a 3/8″ nap paint roller and a paint brush to achieve a uniform coat. Allow 3-5 hours to cure properly.
1 U.S. gal = 150 to 300 sq. ft. /3,79 L = 13,9 to 27,9 m2 (actual coverage is generally less than stated by manufacturer.)
Primer Use Cases:
This is my go-to for any challenging substrates or when tile on tile is a viable option. I use it to surface prep before pouring a self-levelling compound in heavy trafficked areas. This primer is about as good as it gets in terms of primers, it’s pricey but the peace-of-mind is well worth it.
Limitations and disadvantages:
While this is a product that promotes adhesion, it’s performance can still be effected by paint, asphalt, wax, oil, sealers, curing compounds, and poorly bonded or incompatible adhesive that is on the surface. If your substrate contains any of these things, I’d recommend sanding and roughing up the surface, otherwise the primer will simply stick to the wax or oil and not the physical substrate. It cannot be used in permanently immersed applications like swimming pools, outdoor ponds or spas.
Loose tiles or flaky adhesive should be removed as they will affect the final result.
If you are not sure if your substrate is suitable to be primed, just shoot me a comment below this article, I actively monitor comments so I should be able to help.
If you have a large job, the 3.5 Gallon bucket works out much cheaper.
Custom MBP Tile Primer
MBP Tile Primer is a more affordable tile primer with similar use cases to the Mapei Prime Eco Grip.
It is also a single part primer that can be used on smooth and porous surfaces. What makes this one different to Mapei is that it has added aggregates to produce a more gritty surface that will aid in adhesion
It is not suited for exterior commercial uses or in areas subject to heavy water saturation or immersion – keep that in mind!
How To Apply:
Apply Custom MBP with a paint brush, 1/4″ or 3/8″ nap roller.
1 U.S. gal = 150 to 300 sq. ft. /3,79 L = 13,9 to 27,9 m2 – The same as Mapei Eco Prim (actual coverage is generally less than stated by manufacturer.)
Primer Use Cases:
This primer is used in similar cases to the Mapei, be it adhesion to tricky smooth surfaces or even tile on tile. It has a few more limitations over the Mapei so I prefer to use it in residential homes only and in areas that won’t see excessive water like the living areas or hallways. It’s more affordable price-tag makes large jobs easier on the client’s pocket.
Limitations and disadvantages:
This primer has similar limitations as the Mapei; do not apply over paint, wax etc without removing them prior.
This is inherent with any coating. The main things to watch with this tile primer is that it can’t be subjected to heavy water saturation and it can’t be used with Saltillo tile. It also can’t be diluted and requires thorough mixing before use, so if you don’t have a drill mixer, it’s an additional tool you need to acquire.
Custom LevelQuik® Advanced Acrylic Tile Primer
This is a basic, acrylic based tile primer designed for priming concrete floors and fibresheets before tiling or applying a self leveling underlayment.
It’s a great tile adhesive primer and can be applied liberally to substrates.
Acrylic based primers are what I use on a daily for common jobs that are on concrete or fibresheets like HardieBacker. I always keep this stuff in my truck and use it on a daily. Whether I’m tiling or applying topical waterproofing, this stuff is excellent prep for that.
This sort of primer can/must be diluted with clean water as well, meaning that you get more bang for your buck and even more reason to use a tile primer!
How To Apply:
Use a soft bristle broom and sweep it onto the substrate. Any pooling of liquid should be swept to achieve a uniform coat.
If applying over cementitious surfaces, you can dilute the primer 3:1. For example 3 parts water to 1 part primer. Surfaces that are very porous should have a second coat applied once the first one has dried.
1 Quart (946 mL) Porous 1:3 (primer:water) 150 ft² (13.93 M²) to 300 ft² (27.89 M²)
Primer Use Cases:
This tile primer is a great every day primer for situations where you are working over porous and absorbent surfaces. Anyone tiling over a cement floor (old or new) or over a floor that has been covered with a cement/fibreboard, then this primer is more than adequate for the task.
Limitations and disadvantages:
This primer is not suitable to be used over Luan plywood, particle board, parquet, cushion or sponge-back vinyl flooring, metal, fiberglass or plastic. Wooden surfaces should be covered with a backer board first in any case, then you can prime that board with this acrylic primer.
Some metals and plastics can be tiled directly with highly specialist tile adhesives otherwise you’ll need to prime it with one of the other two primers mentioned in this review first.
Tile Primer Drying Times
It is best to obey these curing times, even if the primer seems to be ready to be worked over as the chemicals will still be reacting and achieving a full bond with the substrate. This is especially the case with the thicker primers from Mapei and Custom.
You can open up windows or setup fans in rooms with poor air flow to help with curing.
Tile Primers Conclusion – Your Key To Success
They are an investment in a property and they are also considered a luxury item. You don’t need them in a home or commercial property for that building to be functioning.
Sure, you can buy some dirt cheap tiles and slap em in your rental property because the tenants won’t wreck em as quickly as vinyl or carpet, but the tools and materials required to install those dirt cheap tiles still cost.
So when you’ll be spending all that money, you’ll want to be sure that your investment will last as long as possible and not crumble away after a year or two.
By using a tile primer during the installation phase, can insure your tile investment will last. A little extra money spent today will save you a fortune in redoing it tomorrow.
We looked at three tile primers today that will work in nearly every situation and substrate that is possible to be tiled over.
Mapei’s Eco Prim Grip was deemed to be the best tile primer overall thanks to it’s large field of capabilities and flexibility to be used across a wide range of substrates.
It is also possible to be used as a tile over tile primer, where you can install new tiles over existing tiles.
This is a popular form of renovation and helps saves time and money in demolition time and disposal of the old tile debris.
We also looked at two other tile primers which were more affordable over the Mapei and both featured their unique advantages and use cases.
Hopefully this tile primer guide convinced you to properly prepare your substrates for tiling next time you start a project and will go order your tile primer after finishing up here.