Table Of Contents
- 1 Tile Primers
- 1.1 Tile Primers Introduction – The Downplayed King
- 1.2 Tile Primers – What Is It?
- 1.3 When Can I Use A Tiling Primer?
- 1.4 How To Use a Tile Primer
- 1.5 How To Prepare A surface For A Tile Primer
- 1.6 Tile Primer Use Cases
- 1.7 Best Tile Primers
- 1.8 Custom MBP Tile Primer
- 1.9 HENRY 564 FloorPro Tile Primer
- 1.10 Tile Primer Drying Times
- 1.11 Tile Primers Conclusion – Your Key To Success
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Tile Primers
Avoid Making A Costly Mistake
Planning on starting a tiling project but not sure how to prep your surface? Or maybe you have heard about tile primers and have no idea what they are and whether or not you need to use em?
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?
You need that delicious sticky coating to prep that slice of bread for all the other bits of wonder you’ll be adding to your sandwich.
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.
If you don’t use a tile primer, you face the risk of your tile installation failing prematurely. Anything from 3 months onwards, depending on the amount of traffic.
How does a tile installation fail?
Any tile installation can fail from a lack of using a tile adhesive primer.
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.
I’ve seen this time and time again and when I lift a tile up, it comes clean off the floor and you can see that the substrate is immaculate – no thinset has ever touched it, even though it was technically applied on it.
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?
A tile primer is a liquid tiling product which is used during the surface preparation phase. It is primarily based on latex, polyurethane or epoxy and has the general viscosity of plain water, depending on the type.
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.
It does this by:
• 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
How you apply a tiling primer will depend on whether you are using an acrylic or resin based primer as the thickness of those products is different.
A thick resin-based tile primer like Mapei Eco Prim will require a nap paint roller and a paint brush.
A water-like acrylic based tile primer like Henry 564 will require a soft bristle broom to apply.
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.
1. Remove any debris, blobs of plaster, gypsum, or anything that will create raised points in the substrate.
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.
4. For highly polished concrete floors, mechanical scarring may be needed in order for the tile primer to penetrate it. Use an angle grinder with a diamond grinding wheel to scuff up the surface.
5. Once all preparation has been completed, start from the wall furtherest from the door and make your way backwards. Work slowly and methodically to cover the whole surface area with tiling primer.
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
There are two main types of tiling primers that you may require for your tile preparation work.
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.
This type of primer is thicker and is applied with a painter roller like topical waterproofing.
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.
Coverage:
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.
Buying Tip:
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!
View Manufacturer Info Sheet – View FAQ
How To Apply:
Apply Custom MBP with a paint brush, 1/4″ or 3/8″ nap roller.
Coverage:
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.
HENRY 564 FloorPro 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.
They can 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 1:1. For example 1 quart of primer to one quart of water.
Coverage:
100 to 150 sq. ft. per quart/9.3 to 13.94m2 per 0.9 litres.
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 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.
Tile Primer Drying Times
All primers say that they require atleast 3-24 hours to cure properly. Substrates that are porous will help the primer cure quicker.
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
Let’s face it, tiles are expensive.
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.
All the best for your next project, remember to have fun!
Just wondering can ecoprim be used over glass tiles?
Hi Gord, thanks for the question!
I checked the technical data sheet for you and YES you can use Ecoprim primer over glass tiles.
Hope that helps with your project.
– Carl
Very good information. I am tiling over tile in my shower (I’m thinking it’s porcelain). I used a belt sander with 36 grit on it but you can’t tell so I thought about priming it. Then I read your column on priming. Do I need to use a grinding wheel on it if I’m applying Eco primer. Thanks, David.
Hi David,
Thank you for the comment and dropping by my site.
In theory, the Eco Prim dosen’t require surface preparation but since it is a shower, I would give the existing tiles a blast with an angle grinder. A grinding wheel like this will remove a lot of the shiny surface of the tile and provide a very coarse and excellent gripping surface for the primer. It will bond immensely well if you do that. You can also use a standard stone grinding wheel if you got one, it won’t remove as much material but still buff up the surface nicely.
So, if you got the time – then definitely give it some love with the grinder and then apply the Eco Prim.
Hope that helps,
Carl.
Hi. We put tiles on for floors and they are popping up. Should we remove them and add the primer you recommend to do we have to remove the flooring. Thanks for your help
Hi Dave,
In what way are they popping up? Are they actually just coming off the floor or are they “tenting”? Tenting is when two tiles lift and form a sort of triangular tent shape.
If they are just coming clean off the floor then I would say there would be a few issues as to why this happened. One, yes the surface was improperly prepared and the thinset did not adhere well. A primer would have helped with this. Also, I’m thinking your thinset may have been too dry when you applied the tiles and didn’t bond properly with them. You could also have had a lack of thinset coverage on the tile itself, did you back butter the tiles before setting them?
Without seeing the job I am just throwing out everything that comes to mind, hopefully it gives you some insight. And yes, if needed, lift all the tiles that are loose or easy to lift and apply a primer. Be sure to remove any of the old thinset beforehand.
Thank you for dropping by my website, if you have further questions, please let me know.
Hi Carl: I am a novice at tiling and thought it might be a good idea to PVA over some existing quarry tiles prior to putting some new tiles down.
I have since read this is not the case – can I just now put a primer over the PVA and if so which one – if not what should I do?
Thank you.
Hi Dave, I have replied to your email but for the benefit of other readers I’ll attach an amended version here as well.
Yes, you definitely should not tile over those quarry tiles if you’ve applied a layer of PVA.
Unfortunately the whole PVA glue as a tile primer has caught a lot of well meaning people out. I’m not sure where this idea came from but PVA is not suitable as a primer for tiles for many reasons.
PVA just creates a weak layer between the substrate and the tile adhesive, it’s a glue after-all. So essentially, your whole tile installation rides on how well that PVA has stuck to the substrate = not well.
Also, PVA returns to liquid form if any water touches it, so in high traffic areas, outdoors or wet rooms, water will find a way into that PVA and cause it to be liquid. When it’s liquid, anything above that layer of PVA will become loose and fluid = your adhesive and tile. Which means tiles lifting up, grout cracking etc.
So what should you do?
If it’s possible, I’d try remove as much of the PVA from the quarry tile as possible. A wet sponge and a bucket of water should help. If it’s thick enough, you might be able to just peel it off.
Then you can apply some Mapei Eco Prim Grip over the quarry tile and that will make it ready for tiling. You can use alternative brands if Mapei isn’t available in your area. Custom MBP is another alternative.
I know all this sounds like a lot of hassle but it’ll be well worth it in the long run. Why invest so much time and effort into putting in new tile if it’ll fail in a years time (PVA primer jobs usually fail within 6 months).
Hope that helps!
hi, what primer would i need for thistle dri coat for tiling
Hi Allan,
A standard acrylic tile primer can be used to prime over plaster.
Hi, Just wondering what to use over the sticky adhesive left on my plywood after removing vinyl flooring. I removed as much as I could , but can still feel it sticking to my shoes as I walk over it. The floor was laid 14 years ago and putting down tile now. I was told by a friend to use Mapei Primer T. Is that ok or Mapei Eco-Prime Grip? Thanks for your advice!
Hi Lou,
Mapei Primer T is a general purpose acrylic primer. If the plywood is heavily saturated with the residue, then go with Eco-Prime, but if it’s only in places and not too thick, then Primer-T should be adequate.
You can always rough up the residue with some sandpaper or a cup grinder as well to be extra safe.
Hope that helps.
Carl,
I am prepping my concrete floor laundry room for tile and the first order of business was to scrape up some tile, and two layers of old vinyl. Now I’m left with a black adhesive on the concrete. I’m thinking I could prime with the Eco Prim, feather the floor into a newly installed floor drain (with concrete?), apply some self leveling concrete to address some low spots, install decoupling membrane, and finally install my porcelain tile. Could you comment on this approach? What would you use to slope towards the drain? Do you think the Eco Prim would adhere to the old black adhesive? -Thanks!
Tyler
Hi Tyler,
Your plan sounds excellent. You can feather the slope with a mud screed as long as you have a minimal thickness of 3/4″.
I’m not too sure about that black adhesive, technically if it’s bonding well with the substrate beneath, you can roll with a primer and continue tiling. I’d try rough up the adhesive first with either sandpaper or a grinder and then prime. In any case, Eco Prim will work great on that surface.
Hope that helps.
Carl,
Thanks for the advice. I noticed that the Mapei thunder I have requires any new concrete to have a cure time of at least 28 days. Does that apply to the mud as well? Also, if the mud requires at least 3/4” thickness how can I manage to taper off to near zero by the time I get to the drain?
Sorry…thunder should be thin-set. Lol
Hi Carl,
I’m tiling a painted porch that gets some water when it rains in San Francisco but stays dry the rest of the time. I need to put some self leveler in a couple areas, was planning to use hardibacker and redgard. I see now that I probably don’t need the hardibacker but since I have it already…
So, what kind of primer goes on the painted porch first? Then I was going to use thinset with a primer to attach the hardibacker, use the self leveler for the low spots, use the primer you suggested over the hardibacker and self leveler, then redgard, modified thinset, tile. Tile is porcelain 12 x 12.
Thanks!
Hi Xan,
I would recommend you sand down the paint first and get rid of any flaking patches. You won’t need to fully remove all of the paint but roughing it up and removing any loose areas will go a long way towards getting a proper bond with your primer. I’d say you can just go with a standard primer after that. If the paint on the porch is too thick or creates problems, you can apply Eco-Prim as it’ll bond very well to it.
Good luck with your project and I hope that helps.
Question: I need to re-tile a deck that is over my kitchen. Currently the deck has tile. Can I use Mapei Eco Prim and tile over existing tile outside? The deck is exposed to outside weather such as rain and sun. I live in Southern California. What is your recommendation?
Hi Rudy,
Mapei states that Eco Prim is suitable for exterior walls and floors, so it should be fine to use over those old deck tiles. As long as their structurally sound and not loose, you shouldn’t have any issues.
When doing a shower with hardi backer, should I use a primer and if so which one before I use aguadefence?
Hi Aaron,
Yes, any type of topical waterproofing will require a primer. Otherwise it won’t achieve a proper bond with the backer board and may peel off. Primer-G from Mapei is compatible for your waterproofing and substrate.