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Technically, after the tile is installed over the backer board that gap between it and the tub ledge should be filled with an ASTM C920 sealant (caulking e.g. silicone). Although some say you should have weep holes along this gap so any water behind can weep out into the tub.
Does cement board go over tub lip?
The best approach when installing cement board or other tile backer around a tub is to keep the cement board out of the lip area. above the lip of the tub. Then apply a generous amount of thin-set to the bottom bathtub tile and position it 1/8 in.
How do you fill gap between bathtub and wall?
Fill gaps up to 1/4 inch in width with caulk. If you have tile on the wall adjoining the tub, select a caulk that matches the color of the grout. If your gap is smaller than 1/8 inch in width, use regular caulk; fill gaps larger than 1/8 inch with a sanded caulk.
Can you caulk cement board in shower?
In the event the caulk seal between the bottom row of tile and the tub/shower fails, water can get behind the tile. The best thing to do is to hold all tile backer boards up 1/4 inch from these ledges. Then, before installing the tile, apply a bead of pure silicone caulk between the backer board and the ledge.
Should cement board overlap the tub?
ANSWER – No there should not be a gap between the top of the bathtub flange and the backer board on the wall. The backer board should overlap the tub flange so the tile has a stable backing to attach to. This requires shimming the backer board out from the studs so the wall is plumb.
How do you fix a big gap between tub and floor?
Step 1: Measure the gap between tub and floor tile. Step 2: Pick the right caulk. Step 3: Assemble the caulk gun. Step 4: Apply the caulk on the gap. Step 5: Smooth out the caulk using your finger. Step 6: Give some time for the caulk to dry.
How big of a gap can I caulk?
A single bead of caulk can fill gaps up to 1/4 inch. If the gap is slightly larger than this, fill it with a bead of caulk deeper into the gap, but not flush with the surface. Wait until the caulk is completely cured before coming back to put a surface bead on.
Do you need a vapor barrier behind cement board?
If it’s a cement board, you need a vapor barrier, because cement retains moisture, which means the wood next to it is always damp.
Does cement board need a gap?
Leave a 1/8-inch gap between each backer board sheet. The corners and edges of the sheets should not touch one another.
Does Hardie board need a gap?
Hardie siding requires a minimum 2” gap from all hard surfaces like decks or rooflines, and at least 8” from any soft surfaces like grass, dirt, or gravel.
Can you use thinset to fill gaps?
Thin Set is Not Meant to be a Filler When used as filler, especially when it is thicker than the recommended thickness after the tile is embedded, the mortar can shrink at different rates during its curing process.
Do you need to use RedGard over cement board?
You really don’t need the RedGard, but the more protection the betterso go for it. And yes, you can do the boards beforehand. But, hit the filled seams & screws (your weak points) as soon as a panel is ready to give it some time to setup.
Can you tile directly on cement board?
Cement board forms a durable, stable base for tile, and it has no organic materials (unlike drywall, greenboard, or plywood) so it is not prone to mold, rot, shrinkage, or decomposition due to moisture. Ceramic tile laid over cement board is one of the most durable floor or wall surfaces you can install.
What do you put on seams of cement board?
Use special mesh tape on seams Cover all of the corners, joints and seams, including the joint where drywall and cement board meet, with the fiberglass mesh tape.
What do you put between tub and tile floor?
Since you are joining two different materials together, you should use caulk in the space where the floor tile and tub meet. Grout is not flexible, so it’s not the best material for the job, while caulk allows for movement and also provides a better sealant.
What do you put between tub and floor tile?
Caulk seals seams between tile and fixtures or walls. Caulk provides a waterproof seal where tile abuts other materials, such as bathtubs, sinks, or walls. A carefully run line of caulk (known as a bead) in these areas adds a finished touch.
What do you put around a bathtub?
For caulking around a bathtub, Tom recommends using anything that is 100% silicone. In the segment, he used 100% Silicone Sealant in White, which is manufactured by Gorilla Glue.
How do you fill a large gap before caulking?
Using foam backer rod to fill a wide crack before caulking. One of the best ways to save energy in your home is by caulking any cracks around windows and doors. While caulk alone can be applied to narrow cracks, gaps wider than 1/4” should be filled with foam backer rod first.
