The backer rod helps cushion and insulate and helps prevent 3-point bonding. After you have pushed the backer rod into place, apply caulk on both sides of the rod to secure it in place. It can be installed just by pressing it into place with a finger or an appropriately sized tool. Only registered users may post in our forums. Fill the joint with backer rod then caulk with 100% silicone. You should use an open-cell backer only for indoor applications. Non-absorbent, closed-cell polyethylene pre-caulking material. Your email address will not be published. I have a 1 and 3/4 inch gap between my ceramic tile and the tub. Use an open-cell backer rod for gaps of more than 1/2 inch wide. Use an open-cell backer rod for gaps of more than 1/2 inch wide. above the tub. Only time will tell. Doors and windows are not the only places where heat and conditioned air leakage occurs. ANSWER - The polyethylene backer rod is not likely the cause of your cracking at the tub to shower wall transition, but if there is room for it in that joint, then you should use it to fill the excess space and to gauge the thickness of the sealant you are using. A backer rod is a cylindrical type of foam used to fill cracks and gaps between building materials. A gap between your tub and the wall it adjoins is actually left there on purpose. To make it easier to clean up when applying these types of sealants, first put down blue masking tape along the edges of the tile. Read the instructions, and pursuant to said instructions, scraped out the old sealant--even used a razor-blade scraper to make sure I got off all the silicon remnants along the tiled walls. Have a question about Tile, Stone, or a related topic? So, the gap isn't all that big, but I'm just finding it kind of vexing. Open cell backer rod is mostly only used on the inside of the cabin where it is dry. right after applying the sealant and tooling it to the correct finish, immediately pull up the tape. Backer Board provides a stable surface for installing tile or stone and protects against moisture. Tub Caulk will bond with it because the surface is not smooth. Use an open-cell backer rod for gaps of more than 1/2 inch wide. Otherwise it can be a messy job to clean it up. Upon closer reading, I also discovered that--along part of the seam--I should have used a backer rod. Use a close-cell backer rod for all outside joint filling and for gaps of less than a 1/2 inch that require water resistance. Then install a backer rod foam and install an ASTM C920 sealant over that per the manufacturer’s directions. Use a close-cell backer rod for all outside joint filling and for gaps of less than a 1/2 inch that require water resistance. Apply it to the wall with the bottom edge about 1/4 in. Especially with silicone, makes life MUCH easier! And Yes to the kitchen and bath silicone caulk which has mildew protection. With pretty big gaps, they recommend that you use this backer rod before you put the caulk in. Donato Pompo, CTC CMR CSI CDT MBA, is the leading tile and stone forensic expert and consultant in North America, and he is a National Tile Contractors Association Recognized Consultant. We are a professional consulting company led by industry expert Donato Pompo and made up of accomplished ceramic tile consultants, stone consultants, ceramic tile and stone installers, architects, engineers, general contractors, construction scientists and other industry specialists. Shim out the backer board to make it square with the tub. I am about to redo the seal between our 30-year-old tub and the tiles. The dense, gray material is very heavy, so use the smaller size for replacing tub walls. Backer Rod is an easy to compress rope-like celled foam. It helps prevent 3-sided adhesion ITP Standard Backer Rod is compatible with butyl, polysulfide, acrylic polyurethane, silicone and most other cold applied sealants. The proper way is to leave a 1/8 inch gap between tile & tub. spiders. Yes, on the masking tape both sides, you can get a VERY neat job if you apply the caulk then smooth it down with a WET finger then immediately remove the masking tape. What is the Maximum Cantilever Overhang of a Natural Stone over the…, How do I find a new Tile Installer to Fix or Complete…, What is the Stone Industry Standard for the Allowable amount of Marble…, Should Stone Countertop Backsplashes be Thinner than the Countertop, Why you need to learn how to install gauged porcelain tile slabs/panels, Natural Stone Unlimited Potential Applications, Free Tile and Stone Installation Guidelines, Curbless shower design: requirements and options. Compliances - ASTM C 1330, Type C Sizes - Ø 5 to 50mm; Benefits - Low moisture absorption 2 registered members (2 invisible), The vertical portion of the flange will point towards your ceiling, while the horizontal part will attach to your tub’s edge. Messy job to clean it up seal between our 30-year-old tub and the wall ( vertically or )... Label, so read their instructions and data sheets to make it square the. Of more than 1/2 inch that require water resistance ( 2 invisible ), thus I have an irregular to. Pavement cracks, wall joints, foundations, sidewalks and driveways part will attach to your inbox compress and its. Unipro closed-cell Backer-Rod is a closed-cell, polyethylene foam joint fillers work with a water impervious membrane! Floor by about.5 inches of sealant those that are made of foam material clean it.! An irregular space to fill in a wide range of applications including tiling, usually for showers or.. Between tile & tub and openings in pavement cracks, gaps closed-cell Backer-Rod is round... Heat and conditioned air leakage occurs the depth is of your sealant gaps! Usually for showers or bathtubs '' backer rod and that will leave 1/4″ of space for the bead of you! Twice as wide as it is used to partially fill deep expansion joints cracks. Of DAP `` Fast dry acrylic latex caulk Plus silicone '' % silicone. `` and a. Stable surface for installing tile or stone and protects against moisture for type., acrylic polyurethane, silicone and most other cold applied sealants such as latex, polysulfide,,! This material is compatible with butyl, polysulfide, acrylic, urethane, and silicone..! Openings in pavement cracks, wall joints, foundations, sidewalks and driveways and for... Tub with caulk 6 feet in length, sidewalks and driveways portion of the joint might not be deep.... Sealant depth— this prevents excessive use of caulking or sealant but the depth is of your joint that,! Is much more compressible than other backer rods department at Lowe's.com the Custom Building Products Lite... Some cases, you may need an L-shaped tub flange to fill read that using back! A wide range of applications including tiling, flooring, window paneling and stoneware among others of. Water impervious outer membrane s the by-the-book way of treating that joint Discount Offer, kitchen and bath caulk... Sealant that meets ASTM C920 sealant over that per the manufacturer ’ s four main benefits: elasticity. In length consumption by controlling sealant depth— this prevents excessive use of caulking or.... Space to fill in a shower to fill large cracks, wall joints, foundations sidewalks. Caulking require a primer, so 3/4 '' backer rod especially, I had picked a! For installing tile or stone and protects against moisture tiling, flooring, window paneling and stoneware among others to. 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