How to Tank a Bathroom Before Tiling

Right, so you're thinking about tiling your bathroom, which is great. But before you get all excited with your new tiles and grout, there's a really important step you can't skip. It's called tanking, and it's basically waterproofing the walls and floor in the wettest areas. I know, it sounds like a bit of a faff, but trust me, it stops all sorts of nasty problems down the line, like mould and damp, and even tiles falling off. So, let's get into how to tank a bathroom before tiling, making sure your new bathroom looks good and stays that way.

Key Takeaways

• Waterproofing your bathroom walls and floors before tiling is a must to prevent water damage, mould, and structural issues.

• Proper preparation is key: surfaces must be clean, dry, with all gaps and joints sealed.

• You can choose between liquid tanking kits or waterproof tile backer boards, each with its own benefits.

• Reinforce all joints, corners, and pipe penetrations with special tapes for a complete waterproof seal.

• Always allow the tanking product to cure fully according to the manufacturer's instructions before you start tiling.

Understanding The Need For Bathroom Tanking

Right then, let's talk about why you absolutely need to 'tank' your bathroom before you even think about getting those tiles on the wall. It might sound a bit technical, but it's really just a fancy word for waterproofing. And in a bathroom, where water is pretty much everywhere, this step is non-negotiable. Skipping it is like building a house without a roof – you're just asking for trouble down the line.

Why Waterproofing Is Critical Before Tiling

Think about it: your bathroom is a constant battleground against moisture. Showers, baths, even just condensation – it all adds up. Tiles and grout, while looking nice, aren't completely waterproof. Water can, and will, find its way through tiny gaps, especially if grout cracks or sealant fails over time. If that water gets behind your tiles and onto the wall structure, you're in for a world of hurt. We're talking mould, rot, and eventually, your tiles might even start to fall off. Proper waterproofing creates a barrier, stopping water in its tracks before it can cause any damage. It’s about protecting your investment and keeping your bathroom looking good for years to come.

The Risks Of Water Ingress Behind Tiles

So, what exactly happens if water gets behind your tiles? Well, it’s not pretty. The materials behind your tiles, like plasterboard or even some types of plaster, are often not designed to be constantly wet. When they get soaked, they can start to break down. This can lead to:

• Mould and Mildew Growth: This isn't just unsightly; it can be a health hazard.

• Structural Damage: Woodwork can rot, plaster can crumble, and even the wall structure itself can be compromised.

• Tile Failure: The adhesive holding your tiles can lose its grip, leading to loose or falling tiles.

• Costly Repairs: Fixing water damage is almost always more expensive and time-consuming than preventing it in the first place.

It’s a domino effect. A small leak, if left unchecked, can turn into a major renovation project. You might even find your home insurance won't cover the damage if it's found that proper waterproofing wasn't carried out.

Compliance With Modern Building Standards

It's not just about avoiding problems; it's also about following the rules. Building standards, like the BS 5385-1 code of practice for tiling, now strongly recommend or even mandate waterproofing in wet areas. This applies to domestic bathrooms and showers, not just commercial spaces. Basically, if water is likely to come into contact with your walls or floor, it needs to be protected. This means using a suitable waterproofing system, whether that's a liquid membrane or waterproof tile backer boards, before you start tiling. Sticking to these standards means your work is up to scratch and you're less likely to face issues later on.

Preparing Your Bathroom Surfaces For Tanking

Right then, before we get stuck into the actual tanking, we need to make sure the surfaces we're working on are in tip-top condition. Think of it like getting a wall ready for paint – you wouldn't just slap it on a dusty, bumpy surface, would you? Same idea here, but with water. Getting this bit wrong means all your hard work with the tanking kit could be a bit pointless.

Ensuring A Clean And Dry Substrate

First things first, give your walls and floor a good once-over. They need to be completely clean, dry, and free from any dust, grease, or old adhesive. Any little bits of gunk left behind can stop the tanking from sticking properly. If you've just finished plastering or boarding, make sure it's bone dry. You can check this by giving it a good feel, or if you're really unsure, a cheap moisture meter can be a lifesaver. A clean, dry surface is the absolute bedrock of a good tanking job.

Addressing Gaps And Joints

Now, have a good look for any cracks, holes, or gaps, especially where walls meet or where pipes come through. These are the weak spots where water loves to sneak in. You'll want to fill any significant cracks or holes with a suitable filler or sealant. For joints, like where two plasterboards meet, or where a wall meets the floor or bath, you'll need to use a specific waterproofing tape. This tape gets embedded into the tanking material to create a really strong, watertight seal. It’s a bit like putting a plaster over a cut – it protects the vulnerable bits.

Priming For Optimal Adhesion

Most tanking systems will tell you to use a primer. This isn't just an extra step to annoy you; it actually makes a big difference. The primer helps the tanking material stick to the surface much better, giving you a more reliable barrier. It also helps to even out the absorbency of the surface, so you don't get patches where the tanking dries too quickly or too slowly. You usually apply it with a brush or roller, just like paint, and then let it dry completely. It’s worth checking the specific instructions for your chosen tanking kit to see what primer is recommended and how long it needs to dry.

Don't rush this preparation stage. Taking your time now to get the surfaces perfectly clean, dry, and sealed will save you a lot of potential headaches down the line. It’s the foundation for a bathroom that won’t leak.

Choosing The Right Tanking Solution

So, you've prepped your bathroom surfaces and now it's time to pick the actual waterproofing system. This is where things can get a bit confusing, as there are a few different ways to go about it. Don't worry though, we'll break down the main options so you can make a good choice for your project.

Exploring All-In-One Tanking Kits

These kits are often a good starting point, especially if you're new to tanking. They usually come with everything you need: a primer, the waterproof coating itself (often a liquid membrane), and reinforcing tape for the tricky bits like corners and joints. They're designed to be pretty straightforward to apply, almost like painting. An all-in-one kit can be a cost-effective and relatively quick way to get your bathroom waterproofed. You can typically cover a decent area in under an hour, and often, you can tile over it the next day. Just be sure to check the manufacturer's instructions regarding drying times, especially if you're using a specific type of tile adhesive.

Considering Tile Backer Boards

Another popular method involves using tile backer boards. These are rigid boards, usually made from materials like XPS or cement-bonded foam, that are specifically designed to be tiled onto. They are waterproof as standard, which means you're essentially creating a waterproof substrate from the get-go. This can save you time on applying liquid membranes over large areas. They also offer a good weight capacity, which is important if you're planning on using larger, heavier tiles. Some people find them easier and faster to install than liquid systems, especially if they're replacing existing plasterboard.

Understanding Weight Capacity Of Wall Materials

This is a really important point that often gets overlooked. When you tile a wall, you're adding a significant amount of weight. The tanking system, or the board you're using, needs to be able to support this weight, along with the adhesive. Different wall materials and tanking solutions have different weight capacities. For instance, standard plasterboard might only support around 32kg/m² when directly tiled, but adding a tanking membrane or using a tile backer board can increase this significantly. It's worth checking the specifications for both your chosen tanking product and your wall substrate to make sure they're compatible. You don't want your tiles and waterproofing to start failing because the wall can't handle the load.

Here's a rough idea of what some common boards can handle:

Material	Approx. Weight Capacity (kg/m²)
Gypsum plasterboard (skimmed)	20
Gypsum plasterboard (direct)	32
Plywood (WBP)	30
Gypsum fibre boards	35-40
Waterproof Tilebacker Boards	Up to 62
Glass reinforced cement sheets	Up to 50

Always check the manufacturer's data for the specific products you are using, as these figures can vary. Getting this wrong can lead to serious issues down the line.

Ultimately, the best choice for you will depend on your specific bathroom, the type of tiles you're using, and your own comfort level with DIY tasks. For many, a good quality all-in-one kit or tile backer boards provide a reliable way to achieve proper bathroom waterproofing.

Applying Your Chosen Waterproofing System

Right then, you've got your surfaces prepped and you've picked out your waterproofing kit. Now comes the bit where you actually get it on the walls and floor. It’s not rocket science, but you do need to be a bit careful to make sure you don't miss any spots.

Step-by-Step Application Of Liquid Membranes

If you've gone for a liquid membrane, which is pretty common these days, you'll usually apply it with a roller or a brush. Think of it like painting, but with a much more important job. You'll want to get a good, even coat on everything.

1. Start with the corners and edges. These are the bits most likely to let water sneak through, so give them extra attention.

2. Apply the first coat. Work your way across the walls and floor, making sure you get full coverage. Don't leave any patches bare.

3. Let the first coat dry. Check the product instructions, but usually, you'll need to wait a few hours before applying the second coat.

4. Apply the second coat. Again, aim for an even finish. Some people like to apply the second coat in a different direction to the first, just to be absolutely sure you've covered everything.

Remember, the goal here is to create a continuous, unbroken barrier. Any gaps or thin spots will be weak points.

Reinforcing Joints And Corners With Tape

This is a really important step that a lot of people might skip if they're not careful. Where walls meet, or where walls meet the floor, these are the places water loves to get into. You'll usually use a special waterproofing tape for this. You stick it into the wet membrane in the corners and along any joints.

• Corners: Use pre-formed corner pieces if your kit comes with them, or cut strips of the membrane tape to fit. Press them firmly into the wet membrane.

• Joints: Any place where two pieces of backer board meet, or where the wall meets the floor, needs this tape.

• Pipe penetrations: Don't forget around any pipes coming through the wall or floor. Use tape or special collars to seal these areas properly.

This tape adds strength and flexibility to these vulnerable spots, making your waterproofing much more reliable. It’s a bit like putting extra reinforcement bars in concrete. You can find specific tapes designed for this purpose, like AquaTank Upstand Tape which is great for wet areas.

Achieving A Seamless Waterproof Barrier

Once all your coats are on and the tape is in place, you should have a continuous, rubbery-looking surface. It should feel solid and smooth, with no obvious weak spots. If you used a liquid membrane, it should look like one solid sheet, even over the joints where you used tape.

• Inspect your work: Have a good look over everything. Are there any shiny spots where the membrane looks thin? Any bubbles or peeling bits?

• Touch up any missed areas: If you spot any thin patches, apply a bit more liquid membrane.

• Check the overlaps: If you used sheet membranes, make sure the overlaps are properly sealed and there's no way water can get underneath.

Getting this right means your bathroom will be protected for years to come. It’s worth taking your time with this stage. You're essentially building the first line of defence against water damage, and that’s a pretty big deal for the longevity of your bathroom. For more on fitting shower systems, check out concealed shower system.

Essential Waterproofing Accessories

While the main waterproofing membrane does most of the heavy lifting, there are a few extra bits and bobs that really help make sure your bathroom stays dry. Think of them as the supporting cast that makes the star performance possible. These accessories are designed to tackle those tricky spots where water might try to sneak in.

Utilising Waterproof Movement Matting

Sometimes, especially with timber floors or underfloor heating, there's a bit of movement in the substrate. This movement can cause tiles to crack over time, and if the waterproofing isn't flexible enough, it can fail too. That's where movement matting comes in. It acts as a decoupling layer, meaning it absorbs the stress from the substrate before it can reach your tiles and the waterproofing. It’s a bit like putting a shock absorber on your bathroom floor. It also adds another layer of defence against moisture, which is always a good thing in a wet area. You can find this type of matting designed for use over concrete, timber, and even heated floors, and it usually doesn't add much height, which is handy for renovations.

The Importance Of Waterproofing Tapes

Corners, joints where walls meet floors, and around pipe penetrations are the usual suspects for leaks. Standard waterproofing membranes might not always seal these areas perfectly on their own. This is why specialised waterproofing tapes and pre-formed corner pieces are so useful. These are typically made from a flexible, waterproof material with a strong adhesive backing. You apply them directly over the joints and corners, usually after the first coat of liquid membrane, and then cover them with a second coat. This creates a robust, continuous waterproof barrier that can handle the stresses and movements in these vulnerable areas. Getting these details right is key to a truly leak-free bathroom.

Sealing Critical Points Like Pipe Penetrators

Even the best waterproofing system needs a little extra attention in certain places. Think about where pipes come through the wall or floor – these are prime spots for water to find a way in if not sealed properly. You'll want to use flexible sealant or specific waterproofing tapes designed for these penetrations. Make sure the tape overlaps the pipe and the surrounding waterproofed area generously. It’s also a good idea to extend your waterproofing up the walls from the floor by at least 150mm, creating a sort of tray effect to stop water from getting behind where the wall meets the floor. This simple step significantly reduces the risk of water ingress. For a complete waterproofing system, consider looking at products that offer a full range of accessories to cover all these vulnerable points.

Accessory Type	Primary Function
Movement Matting	Decouples substrate from tiles, absorbs movement
Waterproofing Tapes	Reinforces joints, corners, and transitions
Pre-formed Corners	Seals internal and external corners effectively
Pipe Collars/Sealers	Seals around pipe penetrations in walls and floors
Flexible Sealant	Seals gaps around fixtures and edges

Allowing For Curing And Tiling

Right then, you've gone and applied your tanking system, which is brilliant. But hold on a minute, you can't just slap tiles on straight away. Patience is key here, just like waiting for paint to dry, but a bit more important, really. You need to let that waterproof layer do its thing and cure properly. Skipping this step is like building a house on sand – it’s just asking for trouble down the line.

Understanding Drying Times For Tanking Products

Different tanking products have different drying times, and it’s super important to check the manufacturer’s instructions. Some liquid membranes might be touch-dry in a few hours, but that doesn’t mean they’re ready for tiles. They often need a good 24 hours, sometimes more, depending on the temperature and how humid it is in the room. If you’re using tile backer boards, they’re usually ready to go straight away, which is a bit of a time saver, but you still need to make sure any joints or screw heads are properly sealed and cured if they needed a separate treatment.

Preparing For Tile Adhesive Application

Once your tanking is fully cured, give it a good once-over. You want a nice, even surface. If there are any high spots or ridges from the tanking, you might need to gently sand them down so your tiles sit flat. Also, check for any areas that might have been missed or look a bit thin; you might need a second coat in places, but make sure that first coat is dry before adding another. It’s all about getting that perfect, consistent barrier before the tiles go on. You can find some good advice on preparing surfaces for tiling over at bathroom tiling advice.

The Final Steps Before Grouting

After your tiles are all stuck down and the adhesive has cured – and remember, that usually takes at least 24 hours, sometimes longer if it’s chilly – you’re nearly there. Before you even think about grout, give everything a quick wipe down to remove any dust or stray bits of adhesive. Then, it’s time for the grout. Apply it evenly, making sure to fill all the gaps between the tiles. You’ll want to wipe away any excess grout with a damp sponge after about 15-30 minutes, being careful not to pull the grout out of the joints. This is the last bit of the tiling process before you can admire your handiwork. It’s a good idea to let the grout cure properly too, usually another 24 hours, before exposing it to any real moisture. You can find more on the final stages of grouting in this guide to tiling a shower.

It’s really tempting to rush through the drying stages, especially when you’re excited to see the finished bathroom. But trust me, taking the time to let everything cure properly is the difference between a bathroom that lasts for years and one that starts showing problems like mould or loose tiles way too soon. It’s worth the wait!

Here’s a quick look at typical curing times:

Product Type	Typical Curing Time (before tiling)
Liquid Membrane	24-48 hours
Tile Backer Board	Ready for tiling immediately
Tile Adhesive	24-48 hours
Grout	24-72 hours

After your new bathroom is fitted, it's important to let the materials settle. This waiting period, often called curing, allows everything to bond properly before tiling begins. It ensures a strong, long-lasting finish for your beautiful new bathroom. Want to know more about the process or need a quote for your own bathroom renovation? Visit our website today!

So, What's the Takeaway?

Right then, we've gone through why it's a good idea to get this tanking job done before you even think about sticking tiles on. It’s not just about stopping a bit of water; it’s about making sure your bathroom doesn't turn into a damp, mouldy mess down the line. Following the British Standards is a good shout, and honestly, using one of those all-in-one kits isn't as tricky as it might seem. It might take a bit of time, sure, but doing it properly the first time means you won't be facing bigger, more expensive problems later on. Get it done, get it done right, and you can tile away with peace of mind.

Frequently Asked Questions

Why do I need to 'tank' my bathroom before tiling?

Think of 'tanking' as giving your bathroom walls and floors a superhero cape against water! Tiles and grout look tough, but water can sneak through tiny gaps. If it gets behind the tiles and onto the wall material, it can cause nasty problems like mould or even make the tiles fall off. Tanking creates a waterproof shield to stop this from happening, keeping your bathroom looking great for longer.

What areas of the bathroom need tanking?

You need to protect the spots where water splashes around the most. This usually means all the walls and the floor in a wet room, the walls inside a shower cubicle, and the walls around a bath, especially if there's a shower over it. Basically, anywhere water is likely to hit directly or splash onto regularly.

Can I just use regular plasterboard for my bathroom walls?

While regular plasterboard is cheaper, it's not the best choice for wet areas. It can get damaged by moisture. Moisture-resistant plasterboard is better, but the most reliable option is to use special tile backer boards. These are made to be waterproof and give a really solid base for your tiles, especially if you're planning to use heavier tiles.

What's the difference between tanking kits and tile backer boards?

Tanking kits usually involve painting on a special liquid that dries into a waterproof layer, often with tape to strengthen corners and joints. Tile backer boards are pre-made waterproof panels that you fix to the wall first, and then tile directly onto. Both do the same job of waterproofing, but backer boards can be quicker to install and offer a stronger base for heavy tiles.

How long does it take for the tanking to dry before I can tile?

This really depends on the product you use. Some liquid tanking systems can be ready for tiling in as little as 2 hours, while others might need a day or even a few days to dry completely, especially if you've applied thick coats or it's a bit damp. Always check the instructions on your specific product to be sure.

Do I need special tape or accessories for tanking?

Yes, it's a really good idea to use special waterproofing tapes and corner pieces. These are designed to stick to the waterproof membrane and reinforce the weakest points, like where walls meet or around pipes. This helps create a truly seamless waterproof barrier, making sure no water can sneak through those crucial junctions.