This reduces the amount of residual moisture in the slab, will require a shorter drying period, and result in a lower permeability to vapor transmission. If you have additional questions, please contact MFMA's Technical Director at 888-480-9138. Conduct a moisture test on concrete floor. How to Check Moisture Content in Concrete Floors Things to Consider If there is any paintwork on the wall, it must be removed to make the wall suitable for tiling. Over time, hydrostatic pressure will force that moisture upwards and can cause bubbles in surface treatments, and cracks in covering materials that are installed above it. In warm and well ventilated drying conditions allow 1 day per millimetre up to 40mm in thickness, so 40 days if 40mm. . If your subfloor is above 12% moisture, dry out the subfloor before installing hardwood floors. of 13x13 floor tiles over a concrete slab. Electronic Concrete Moisture Meters. Use a polymer-modified, dry-set . Vapor Retarders and Concrete Moisture Vapor Transmission, Donnelly Testing & Inspections (501) 915-0626. Moisture will not damage the vinyl flooring, but will deem the adhesive that secures the vinyl to the slab almost useless. It is important to arrive at a consensus with the client beforehand if the moisture content is above the desired level, to avoid any confusion later. Floor covering manufacturers, whether producers of tile, wood, carpet or high-performance floor coatings, publish the maximum allowable moisture content of the concrete over which their flooring products can be installed, based on results of various ASTM . Then after 24 hours, grout the joints and clean the tiles with a mop or sponge. Due to the different types of electronic concrete moisture meters on the market, MFMA recommends following the manufacturer's instructions for proper on-site testing procedures. Thoroughly clean your subfloor. ft. Clean out the holes using a wire brush and vacuum. Tiling before the curling occurs can cause undesirable debonding of the tile and lippage between adjoining tiles. Quote built accordingto low moisture standards o Less than 6% on concrete subfloor o Less than 14% on wood subfloor If all three readings are consistently high OR if all three readings vary significantly- flagged "RED" RED - potential moisture problem Quote built according to high moisture standards o 6% or greater on concrete subfloor o A three-pound moisture vapor emission rate (MVER) was for years recognized as the limit of moisture that could be safely tolerated by flooring materials and adhesives. If it's drywall on one side and tile on the other then you'll want to install a metal drywall corner before tiling. Any hollowness or cracks need to be rectified to ensure soundness of the screed. Some DIY fanatics have found the best success with adhesive removers after they have allowed their soaked sponge or towel to sit on the old glue overnight, allowing time for the bonds to dissolve. Because water comes in from above. Dex-O-Tex provides high-performance concrete moisture barrier systems that protect your floors from moisture damage and costly repairs. Reading time: 1 minute Concrete slabs on grade and basement slabs are weak and vulnerable to the detrimental effect of moisture which may lead to various problems. Before tiling is laid, the screed needs to have dried to the approved level. Acceptable moisture levels in concrete according to ASTM standard, when testing via ASTM F2170, the RH level of a concrete slab needs to be at or below 75% — unless the flooring system manufacturer provides alternate guidelines. Basically, water damage under tiles can occur in two ways: Because moisture is trapped under the tile covering, or. Concrete slabs all have a moisture gradient: MC is higher at a lower depth than it is at the uncovered slab surface. Use a level to check the floor. Fill seams in the subfloor with caulk. When you install hardwood, laminate, or vinyl flooring over a concrete subfloor, one of the most important steps to take to ensure the lasting beauty and stability of your floors is moisture testing. Discussion in 'Tilers' Talk' started by nev, Aug 20, 2004. Seal the holes with a sensor sleeve and cap to allow them to acclimate for the next 24 hours. Before any type of flooring work is done, check the moisture content of the concrete before continuing. Before you lay the first plank, you must ensure that the moisture level in the concrete subfloor is low enough that it will not affect your . Therefore, a normal moisture meter reading for gypsum is between 0.2% and 1%. When you place new tile over existing tile, you cover the tile joints and cut off the escape route for the moisture. You can perform the ASTM F2170 Relative Humidity (RH) test to see if it currently has excessive moisture. For your porcelain tile to last for long, you need an underlayment. During this time shrinkage occurs to compensate for the volume loss of water. Ideally, concrete should have a pH of 7-9 before installing a floor covering; otherwise, the high alkalinity (high pH) combined with moisture will destroy flooring adhesive bonds. Blue board is mostly used as plaster, and it has a moisture-resistant core. Floor evenness also needs to be checked. The new concrete floor should have a polythene sheet DPM below it to prevent moisture from below migrating or diffusing upwards into the slab. After curing, moisture content should be checked. Drying Times Using Force Drying. As a matter of fact, at lower humidity, concrete with a 5.5% moisture content is still wet, and it has approximately 6.6 gallons per cubic meter more moisture to dry out of it. Flooring moisture barriers are placed beneath the floor's underlayment. 7. A single layer of tile allows any moisture in the concrete to escape through tile joints. Therefore, a normal moisture meter reading for gypsum is between 0.2% and 1%. S-240: 90: 8: 5 to 9: S . If the relative humidity is 54%, then the air can absorb a maximum of 0.008 oz/ft3 of water vapor from the concrete through evaporation before condensation would occur. Reply to newlineuk All advertising can be removed by subscribing. ft. of concrete, and another hole for each additional 1,000 sq. Water reducing admixtures can be used to obtain adequate workability and maintain a low . How moisture gets into concrete Place the sponge or towel on the adhesive; After at least 30 minutes to an hour, test effectiveness; Repeat if necessary. Place concrete directly over an efficient vapor barrier (greater than six-mil poly and puncture resistant). The concrete loses some of its strength, but will still meet code requirements. It is essential to get one for plywood if you are installing a wood subfloor or one for concrete if your subfloor is concrete. Excess moisture is a damaging force to concrete and any materials resting on top of it. With ceramic tile you might be able to get away with up to 90% depending on the tile and installation products you are using. This prevents the floor from sucking the moisture out of the adhesive before it sets and seals in any dust on the surface. The nature, extent and movement of moisture in concrete can be ascertained using a range of tests. Page 1 of 2 1 2 Next > . "There is nothing wrong with tile laid directly on concrete providing all precautions are taken regarding moisture proofing," he says. The code of practice value is stated as 75% relative humidity which equates to 0.5 % moisture content by mass. Do . Penetrating Concrete Sealer Prevents Moisture Problems. . First, it is important to determine if there is moisture coming up from the slab. Use reputable flexible adhesive for tiling on screeds and concrete and as per the manufacturers specifications, DO NOT USE PVA but a latex based primer if the concrete surface is . Both porcelain and ceramic tiles are rigid, so if they are installed on surfaces that are not flat, they can crack easily. 2. A moisture or vapor barrier prevents water from wicking up from the ground, through the sub-floor and absorbing into the hardwood floor. You can test for . A variety of potential external water sources at a worksite can affect slab drying and curing. Keep below grade excavations free of water to prevent potential reservoirs of moisture that can migrate upward through slabs. Apply the Sealer. Measures moisture beneath the surface without drilling holes to a nominal depth of 0-20mm. Specification writing authorities chose 28 days as the standard specimen age to establish consistency for testing procedures throughout the industry (1). To use this method, ASTM D 4263, "Standard Test Method for Indicating Moisture in Concrete by the Plastic Sheet Method," a plastic sheet is tightly taped to the concrete. After 72 hours, a humidity reading is taken under the plastic with a dew point hygrometer. Without the proper moisture barrier, vinyl flooring acts as a moisture barrier, causing it to buckle, bubble and lift. Adequately cure the slab for maximum surface strength and low permeability. If your meter has insulated probes you could drill a few holes and try to get a more accurate reading at 1-2". Relative humidity (RH) in-situ probe test 2. After this period, retained water needs to evaporate away until a normal moisture content is reached. The range of floor screed drying times before tiling is quite wide, and here are examples based on 75mm think application. 5. Two simple surface . For the former, improper tiling is usually responsible. Accelerants are most often used in freezing temperatures when the moisture may freeze before hydrating the concrete. But there's a downside to using an accelerant. Things to Consider Keep Excavation Free of Water. Step 1: Test the moisture content of your concrete subfloor. Our solutions include the VaporControl Primer 200-E and the VaporControl Primer 1P. Why Concrete Moisture Is Tested If excess moisture is present in a concrete slab when an impermeable surface treatment is installed, it will become trapped under that covering. 1. Higher relative humidity . An MVER above three pounds . A: It's perfectly acceptable to put tile directly on concrete — with a couple of caveats. If the concrete is well-established, meaning that it is at least several months old and has already been verified as ready by another professional using the ASTM F-2170 testing method, then a relatively fast surface check might be enough to verify if the moisture content of the subfloor is likely to affect tile adhesive. Use a belt sander to reduce high spots. If the ambient relative humidity is lower, like, 60%, the equilibrium moisture content of concrete is also lower, at 3.9%. Start by marking the center of the room and drawing a guideline that extends out to the walls. You should check the moisture variance by taking 20 readings every 1000 square feet. Unwanted wetness deep within concrete can eventually make its way to the surface, causing problems like: Organic growth such as mold and mildew beneath mats and non-air permeable coverings No water source has a greater impact on the time it will take concrete to dry. Further checks are therefore necessary to verify whether the drywall can be treated or it needs to be replaced. A three-pound moisture vapor emission rate (MVER) was for years recognized as the limit of moisture that could be safely tolerated by flooring materials and adhesives. Tile cannot be attached directly to painted concrete, as the thinset will not adhere well to the paint. Yes, writes Doug McEvers, Ditra will insulate the concrete slab from the tile and lower the potential for thermal storage. Typically your hardwood comes with installation instructions that have the recommended percentages for installation. Perdure MVT - This is a two coat epoxy system that resists high levels of moisture . Such an arbitrary time frame, however, is not . While you can install tile directly on concrete, problems may erupt when the concrete cracks or shifts. Before installing self-adhesive vinyl floor planks or peel and stick PVC tiles, the moisture content of the concrete subfloor should be as low as possible. Although tiles may have an impervious finish, if they are not installed correctly, the joints and substrate may not be waterproof. Instead of sealer, it is also possible to lay a waterproof membrane over the cement. Step 6 - Lay a Membrane. Before placing the membrane, the substrate must be clean and have a moisture content of: concrete or mortar - 75% or less RH; plywood - 20% or less moisture content. Further checks are therefore necessary to verify whether the drywall can be treated or it needs to be replaced. Yet you have other water sources to worry about. In order for concrete to dry, a large percentage of the excess moisture in the slab must be able to reach the surface and evaporate. In the southeast I usually get concrete readings 40-55% R.H. when dry. For instance, lifting tile off the floor, rotting hardwood, damping carpet, and coatings delamination. However, there are liquid solutions that you can apply by brush, roller, or trowel. A moisture barrier is used when installing floors or walls in areas prone to dampness or excess moisture, such as basements, ceilings, or crawl spaces (source). . Porcelain tile is more durable and absorbs water less than ceramic tile. Move the level across the floor and use a marker to mark low levels of the concrete. or less. This form of concrete floor moisture test is valuable in assisting contractors in identifying suspect areas that might require further testing, deeper in the slab, but that testing must be conducted with in situ probes. You can buy a barrier separately or get underlayment with a moisture barrier built-in. Another option is to tape a piece of your vinyl flooring to the concrete for 72 hours. All of the movement in concrete is transferred to . You can also use a brush or a sprayer. This will help you to evenly space the tiles. 4. Level your floor by filling low spots with patching compound and a putty knife. If your subfloor has less than 12% moisture and the floorboards are not within the acceptable range, acclimate the floorboards for seven to 10 days. The majority of commercial and industrial buildings are constructed with a concrete substrate laid over prepared soil, called slab-on-grade. "Tile and grout work loose if the . Use a large carpenter's level to identify low areas of the floor. Hold against the wall to allow a radio signal to penetrate the surface. 2 months ago a hot water pipe leaked underneath and raised the moisture content of the slab throughout the house. Tiles can be applied directly to a clean, smooth concrete slab with a latex Portland cement mortar. Alkalinity is too high in the concrete due to a high moisture emission rate. The concrete should be properly cured, be level to 1/4 inch in 10 feet, and have a steel trowel or fine broom finish. A successful tile installation project requires a level surface. Patricia Gomez says . Preparing a Concrete Subfloor for Luxury Vinyl Flooring. Make sure all sides are firmly secured. Check the plastic to see if any moisture has beaded up on the inside of the plastic. I am installing 80s.f. Due to the different types of electronic concrete moisture meters on the market, MFMA recommends following the manufacturer's instructions for proper on-site testing procedures. This site uses cookies to help personalise content, tailor your experience and to keep . This is not a definitive Concrete Moisture Test. Remove Rotted Wood - After removal we could see the moisture trapped between the wood and concrete floor. An MVER above three pounds . 5 to 9. Prepare a Wood Subfloor for Tile. 7. The majority of commercial and industrial buildings are constructed with a concrete substrate laid over prepared soil, called slab-on-grade. Check your subfloor to make sure it is level. If you find higher values, then your drywall might already have a high MC that could spread and damage the entire board. A new concrete slab will contain inherent moisture, which could affect the tile adhesive. The 28-day period is an arbitrary specimen age - though chosen for many good reasons - for testing the compressive strength of concrete. Before tiling, the MDF wall must be free of dust, oil, and grease. If the flooring comes up easily, you'll need to reduce the . Apply a waterproofing membrane, such as RedGard, to the slab before tiling. The primary source of moisture in a concrete slab is the proportion of water mixed with the cement. Peter Craig and George Donnelly, Moisture Testing on Concrete Slabs, When 3lbs is not 3lbs, Concrete International, September, 2006. Prepare a set number of holes to a depth of 40% of the slab's thickness—at least three holes for the first 1,000 sq. Liquid screed can be force dried, starting 7 days after installation. Use low water to cement ratios in the concrete mix (0.5 max) and four-inch maximum slump without water reducers. Whether a construction or a renovation, you have the peace of mind that you won't deal with moisture problems down the road. If the flooring comes up easily, you'll need to reduce the . squeaky, Aug 20, 2004 #2. . If the concrete retains moisture, the tiles may curl and warp, and the project should be abandoned or the concrete floor should be dehumidified. Concrete relative humidity The results? If you have additional questions, please contact MFMA's Technical Director at 888-480-9138. Electronic Concrete Moisture Meters. Permissible moisture content depends on project requirement. This traps the moisture beneath the tile and can cause loosening of the old tile as well as the new tile. It is more durable than drywall and prevents mildew growth. You can do this with a moisture meter, ensuring that your reading is no more than three-pounds per 1,000 square feet per 24 hours. Excessive moisture below concrete slabs can cause structural degradation of soil bearing strengths, and swelling and shrinkage of soil. 1. level 2. Apply self-leveling compound. Patricia Gomez says . Hi Tile Guy My house is on a concrete slab and the shower was constructed with a mortar bed, smooth river rock was used for the shower floor and cement board with a vapor barrier was used on the walls. Floor covering manufacturers, whether producers of tile, wood, carpet or high-performance floor coatings, publish the maximum allowable moisture content of the concrete over which their flooring products can be installed, based on results of various ASTM . Clean the concrete slab thoroughly before laying tile. If curling occurs (and it often does), the concrete can be ground before it is tiled. Place the tiles on the surface, maintaining an equal distance between the tiles using spacers. Accelerants are most often used in freezing temperatures when the moisture may freeze before hydrating the concrete. After you have cleaned, patched, and repaired the concrete floor, you can now seal it. SAFETY ZONE TILE: S-700,and S-750 : 80. Another option is to tape a piece of your vinyl flooring to the concrete for 72 hours. Also, the wall must be flat, smooth, and dry by filling gaps in the surface with plaster filler. [/FONT] Hope this helps. 3. . Guide to Installing Tile Over Concrete Slabs. Screed should be allowed to air cure based on the period recommended by the manufacturers before tiling begin. Lay the tile directly on the concrete. Some flooring system manufacturers have products that can handle 95% RH or more. StarNet, StarLog, The "Cure" for Concrete Moisture and pH ills, Volume VII Issue 2. This is the best method for assessing the moisture content beneath a tiled / covered surface. 5. in 10 ft. (3 mm in 3 m) and no more than 1/16 in. Once you have the layout marked, begin laying the tiles in the center of the room and work your way out. Grinding The Surface - Madstone used a dustless grinding system to mechanically remove the top cementitious layer and removed potential bond breakers. First, make sure the surface of the concrete is clean and smooth with a floor leveling compound. If it's drywall on one side and tile on the other then you'll want to install a metal drywall corner before tiling. For tiles with at least one edge 15 in. 8394. Step 1: Test the moisture content of your concrete subfloor. As the moisture and cement mix, the concrete starts to settle and harden. When it is applied to green cement it also acts as a curing membrane. Use a concrete mixture with a moderately low water-cementitious material (w/cm) ratio (about 0.50). Many of the membranes can also be applied to freshly laid, or green, cement. Two tests that are generally used to determine moisture content to internal concrete areas. . Added to that, beneath continuous flooring, moisture can also cause floor darkening or […] [8] Mix the self-leveling compound in a bucket according to package directions. When installing tile outside: Choose a tile with a slip-resistant surface that's rated for outdoor use. Any area that exceeds the allowable moisture limit must be further dried to an acceptable level or treated with a moisture remediation system before flooring installation. Full strength may not be achieved for a period of 28 days but screeds should be kept moist for at least 7 days to allow sufficient strength gain before drying is allowed. You can do this with a moisture meter, ensuring that your reading is no more than three-pounds per 1,000 square feet per 24 hours. If installing LVT on a concrete slab, it is important to test the relative humidity (RH) of the concrete slab well in advance of floor prep and tile installation. The three options that can be resorted to under such circumstances are: Wait longer, if the project is not on a strict time schedule Employ a third party to conduct a further test A moisture barrier for hardwood floors can be as simple as a roll of plastic sheeting. 2. Thicker substrates require 2 days per mm. Tiling On Concrete. Alkalinity is measured by pH from 1-14. Wait 48 hours. Moisture within a concrete slab follows a number of small pathways, or capillaries, that form as it combines with the initial mix elements-cement, aggregate, and any other admixtures. An acceptable level is 4.5 lbs. Test the moisture content of your concrete subfloor. Ideally you want a RH of about 75% to 80%. Painted concrete can be made porous with sandblasting or other hard abrasive actions. in 2 ft. (1.6 mm in .6 m) from the required plane when measured from the high points in the surface. 1. Standard Calcium Sulphate - 110 days Traditional Sand and Cemen t - 75-100 days Cementitious Belitex - 21 days Mapescreed 704 - 7 days Hydraulic Binder Fast Drying Screed - 24 hours Ardex A35 - 4 hours Moisture Testing Check for dips in the floor by sliding a 4-foot to 6-foot straight edge in different directions all around the room. The concrete loses some of its strength, but will still meet code requirements. Mark any uneven spots you find so that you can make them level. The options are: (i) Allow the slab to dry out for approximately 1month per 25 mm of concrete thickness Hi Tile Guy My house is on a concrete slab and the shower was constructed with a mortar bed, smooth river rock was used for the shower floor and cement board with a vapor barrier was used on the walls. For example, if tiles are laid on a floor structure that is not sufficiently dry or if there is so-called subsequent moisture from the . As the moisture and cement mix, the concrete starts to settle and harden. Also, should the concrete crack, the crack can be treated (with an anti-fracture membrane) before it is tiled. But there's a downside to using an accelerant. Determining what humidity level is acceptable depends upon the surface treatment . View this as the "test before the test.". Screed subfloors shall be sufficiently dry with a moisture content of less than 75% RH as per AS 3958.2-1992. If you find higher values, then your drywall might already have a high MC that could spread and damage the entire board. An MDF wall cannot be tiled if the wall is exposed to moisture or damp conditions. 3.2 AS 3958.1-2007 states that sand-cement screeds should be "cured for at least 7 days per cm or thickness" before tiling". (0.38m) or longer, the maximum allowable variation is no more than 1/8 in. Stir or shake the sealer thoroughly, then apply it over the floor with a paint roller the way you would to apply paint to a wall, instructs Build Direct. 2. An acceptable level is 4.5 lbs. High moisture content in the underlying concrete can cause future subfloor failure and significant problems with the adhesive that is supposed to be securing the LVT in place.