You can safely install tile on top of green board, which is also known as water-resistant drywall. However, due to the waxy surface of green board it’s essential to prepare the surface by skim coating and sealing it. If green board is not painted with sealer, tiles may fail to adhere to the green board. Although green board is a great wall material for some areas of your bathroom, it is not suitable for use in showers. Shower walls should be constructed using a waterproof board. Green board used in a shower will deteriorate and cause mold to form.
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Can You Tile Over Green Board in a Shower?
Never use water-resistant drywall (also known as “green board”) in a shower. It has the same drawbacks as tiling over regular drywall in a shower. While green board is moisture-resistant, it is not waterproof. Moisture will seep through the grout between your tiles and destroy the green board beneath. Tiles may come loose, mold may form in your walls, and the moisture trapped in the green board can cause your wall studs to rot.
- Do not use green board for shower walls and tub surrounds.
- Water will penetrate shower tile and grout to destroy green board and cause mold in your walls.
- Always use a waterproof backer board for shower walls.
- This waterproof shower kit is a much better choice for shower walls than green board.
Use a waterproof backer board, such as cement board or polystyrene foam panels. Cement board and other truly waterproof backer board will form a moisture barrier that protects your wall. It will also hold up over time where green board will fall apart. Plus, you can tile over waterproof backer board easily.
Can You Tile Over Green Board in a Kitchen?
You can safely tile over green board in your kitchen. Green board is moisture-resistant, making it great for walls in areas that will experience some moisture. This makes it an ideal backing surface for tiled kitchen backsplashes.
- Green board is an excellent backing surface for tile in kitchens.
- You can tile over green board in non-shower areas of your bathroom, such as near sinks and vanities.
Green board can also be safely used as a wall material in portions of your bathroom walls that are not inside your shower stall. So, you can tile over green board installed near a sink. With proper preparation, green board takes tile as easily as standard drywall.
Can You Use Thinset On Green Board?
Standard thinset adhesive can be used on green board as long as the green board has been patched with joint compound and painted with sealer first. A coat of sealer is a must before applying thinset or tiling over green board. If you don’t paint a coat of sealer onto your green board, your thinset will not adhere well. This can lead to tiles popping off the walls shortly after installation.
- You can use thinset over green board if the green board has been properly prepped.
- Prep green board with a coat of sealer before applying thinset.
- Thinset will not adhere well to un-prepped green board, leading to a tile job that falls apart.
The reason sealer is needed to prepare green board for tile is because green board has a waxy coating that helps it resist water. This waxy coating is also slick enough that it can prevent thinset from sticking to the wall. You won’t need a sealer for regular drywall, but if your drywall is green or blue in color, it has a water-resistant coating and must be sealed before you apply thinset and tile.
How to Prep Green Board for Tile
After you have hung your green board with drywall screws, apply a skim coat of drywall compound to the walls. There is no need to use drywall tape for green board seams that will be covered with tile. Instead, fill gaps and low spots with joint compound. Wait 24 hours, then use 100-grit sandpaper to smooth the joint compound.
- Skim coat your walls with joint compound to fill drywall seams and low spots.
- Allow 24 hours for joint compound to dry.
- Sand the joint compound with 100-grit sandpaper.
- Wipe down the walls with a damp sponge after sanding.
- Use a roller to paint the walls with this surface sealer.
- Allow 24 hours for the sealer to dry.
After you sand the drywall compound, wipe the wall with a damp sponge to remove drywall dust. It’s also a good idea to vacuum the room to remove excess drywall debris. Finally, use a roller to paint a single coat of sealer onto the green board the same way you would apply a coat of paint. Wait 24 hours for the sealer to dry. Now, thanks to the sealer, tile adhesive will stick to the green board and allow for a long-lasting tile job.
How Do You Tile Over Green Board?
Once you’ve prepped your green board with a skim coat, sanding, and a coat of sealer, you’re ready to start tiling. Now, you can tile over green board the same way you would any wall. Here’s how:
Outline Your Tile Installation
Mark the edges of the planned tile installation on the wall with a pencil or chalk line. It’s a good idea to mark both the sides and top of the planned installation. When spreading your thinset adhesive in future steps, make sure not to cover these lines. Your tiles should be installed precisely to line up with your markings.
Prepare Your Thinset
If you’re using powdered thinset, mix the powder with cool water until it is the consistency of peanut butter. If you have pre-mixed thinset, you can use it as-is. Once your thinset is ready, spread it on a portion of the wall with a toothed tile trowel. You can start wherever you like, but an edge or corner is typically best.
Press Your Tiles Into Place
Press your tiles firmly (but not too hard) into place in your thinset. Remember, thinset will add some height to your tile installation. Do not press the tile so hard that all the thinset is squeezed out from under the tile. When placing your tiles, make sure they are level and straight. Beginning at a corner and lining up precisely with your marked guidelines makes this easier.
Pay Attention to Spacing
Use these tile spacers to provide a ⅛-inch ( mm) gap between tiles on your wall. It’s also essential to leave a ⅛-inch gap in the corners. Never install tile in a way where one tile is touching another without a gap between them. This makes for unsightly seams that are hard to seal. It can enable water to get between your tiles and the wall.
Cut Tiles as Necessary
As you install your tiles, you will have to trim tiles to fit the dimensions you planned, as well as fit around wall sockets and other fixtures. An angle grinder is a great tool for cutting tile. For precise cuts, this manual tile cutter is one of the best tools available.
Remove Tile Spacers
Once you’ve finished tiling your wall, remove the spacers between the tiles. It’s best to remove spacers within 20–30 minutes of tiling. This prevents them from being glued in place. Never leave tile spacers permanently—they will make proper grouting impossible.
Allow Drying Time
Thinset adhesive may seem dry to the touch relatively quickly, but it can take a surprisingly long time to dry. Allow 48–72 hours for the adhesive to fully set. This ensures the portions under the tile dry thoroughly. Grouting before your thinset is dry can ruin your grout job.
Grout Your Tiles
Use a grout float to fill the gaps between tiles with grout. As you grout, use a sponge and warm water to wipe away excess grout. Once the grout is dry, scrub the tiles with a brillo pad to remove grout haze.
Caulk Corners and Edges
When grouting, do not fill corners where tiles meet, the edges where tile meets the wall, or where tile meets any other surface, such as countertop or cabinet. All of these seams should be sealed with color-matching silicone caulk. Get a color that matches your grout so the caulk is not noticeable.
Can You Install Tile Onto Green Board?
When planning to install tile over green board, keep these guidelines in mind:
- Never tile over green board in a shower—green board is not waterproof enough to be used for shower walls.
- Green board can be used as a tile backing in kitchens and bathrooms (excluding shower walls).
- Never tile directly onto green board that has not been painted with sealer.
- Prepare green board for tile by filling gaps with joint compound, sanding, then painting on a coat of sealer.
- Once green board is prepped and sealed, you can install tile by following the same process used for other surfaces.
Green board is an excellent wall surface for kitchen backsplashes, as well as bathroom walls and ceilings. It provides more moisture protection than standard drywall and helps your home resist mold and mildew. With a couple of extra steps, you can easily tile over your green board to add to the beauty of your home.