That reason is that it isn’t always indicating the moisture in the slab and if it does, you don’t know how much moisture there is in relation to a potential flooring failure. We excavated the old floor and dirt put in a layer of gravel, French drains and a sump pump and then covered with a 14mm vapor barrier. The membrane can then be covered with your chosen surface or gravel. In there, they should spell out “concrete moisture” maximums. So it shouldn't come as a surprise that a roll of fabric is not going to cure the weed problem. Here is also a link for the construction of a slab on slab https://www.concreteconstruction.net/how-to/new-slab-on-top-of-old_o Good luck. Thanks Tracy, Hey Jason. RV-specialty vapor barriers can cost around $0.50 to $0.75 per square-foot, while leveling blocks have a price ranging from $30 to $50. What can I paint onto the subfloor to eliminate moisture coming through when it rains? You may want to also look at power vents that may assist with increased airflow when preset levels of relative humidity and/or temperature levels are hit. I’m avoiding a simple plastic ones for that reason and looking into underlayments that are designed for LVP (such as FloorMuffler LVT). I am sure you probably already have, but I would go back to the respective manufacturers’ installation documents and/or contact them directly with your situation and get their guidance. And adding epoxy resin between the new and old slab. Basement installed by reputable contractor 20 years ago. Installed drop down vinyl plank as per manufacturer – directly in cement. Crawl Space Encapsulation decreases energy loss due to direct moisture absorption. I don’t believe it’s capillary action from the water table because when I pull back an area of the plastic, that area dries out in a day or so. The foundation walls were constructed in 1990, there does not appear to be any moisture leakage through any of the sections of concrete. I think you may be best served contacting nwfa.org. Lastly, here is a link to a tile size/trowel size guideline table: http://www.elitebuilding.com/tile/ref/trowelsize.htm. Should I use a membrane between before pouring self levelling concrete over the pipes? this is why i’m doing the slab so i have one solid and flat floor. What type of moisture barrier would you recommend? If you are unable to find the answer in their written documentation, I would call their technical center. While a water vapor permeance of less than 0.3 perms is recommended, a higher permeance rate is usually considered acceptable for residential use. However, in case you are parking your RV in the grass, make it a point to include a vapor barrier in between the tires and the ground. Therefore, there needs to be something underneath the slab that prevents vapor moisture from entering. I don’t claim to be a radiant heat slab construction expert, but I would think you would want things as dry as possible prior to the pour. No coupon code available. Hi Jason According to the Guide to Concrete Floor and Slab Construction published by the American Concrete Institute, a vapor retarder should not be less than 10 mils thick. isn’t worth a crap now. How can I tell if there is one? Based on these, I would guess the slab will require some type of product be applied to the surface to slow down the vapor that is coming through the slab. Never punch holes in the vapor barrier to allow bleedwater to escape. The floor level is techinically 15″ above grade the way our yard slopes. Doing this lets you see what to expect if you did the whole job. Looking for a low-mold home isn’t easy or cheap. Today, most slabs experts recommend placing the slab directly on the vapor barrier unless the subbase is protected and can be assured of staying dry. I will send you an email shortly with some additional information and attachments. I’m considering building a new home and the new home builder does not install a vapor barrier underneath the slab in the basement. Based on your situation, it may be best to ensure you have proper ventilation and airflow in the air space. Right now all my wood is stacked on top of 3x5 landscape timbers and I have noticed the bottom 2-3 rows of … That being said, I doubt some moisture (you didn’t say how much) would be a huge problem as long as you gave the flooring assembly ample time for the moisture to escape and dry, prior to installing a finished floor. There’s only one-way moisture leaves concrete, though, and that’s via its surface. Here is what im working with: 1950's Cape Cod, Brick, 5' crawl (approx 1200sq feet). I remember when the floor was installed there was a foam underlayment but I to not remember it having any plastics on the bottom side. We found that under the clay tile, It wasn’t concrete slab. The science surrounding concrete is complex. i know correct thing to do is to replace the pad but i cant. Help me!???? Here are the parameters: Materials can be separated into four general classes based on their permeance: I hope this help. Good luck on the project. I doubt the slab has a vapor barrier. I don’t see much issue with slab degradation. When using stone mulch, it's important to install a barrier between the soil and the stones.The barrier serves two important functions. Vapor retarders are materials that will minimize the transmission of water vapor from the sub-slab support system into a concrete slab. Seal all vapor barrier seams with the tape provided by the barrier manufacturer. Good luck. First and foremost, follow the manufacturer’s recommendations for a proper, warrantable installation…including installing the 6 mil. With many roll sizes you are … This may help you in your process. I have heard of people doing this, but I would always check local building codes to confirm acceptability. The floor is generally dry, but I’d like to have some vapor barrier protection and the cushion. I hope you are ok. 2. If this was my project and I had done it multiple times without success, I would do a small test area first. I can’t say whether vinyl planking would be better, but I would at least investigate it. We have a home in Houston that has been flooded with the hurricane, and all flooring other than the travertine tile has been removed. VaporStake in Chino Hills, CA, Install boots around all penetrations and blockouts. Livingroom and Hallway have hardwood floors. One option may be to have a coating installed that has some type of slip resistant surface. Obviously, I am not endorsing any of these, but they are products that come up in daily discussions. the floor is not flat or smooth and it has channels in it. Thanks for the comment. Do I run the vapor barrier that’s on top of the mat slab over the new foundation as well? My landscape contractor plans to install a 10 mill vapor barrier on top of the base rock for our new concrete driveway. I would test via a Calcium Chloride test or a relative humidity test like the Rapid RH test. Would you place a vapor barrier against stud wall? I also thought about using a spray foam on the exposed slab and between crevices and on the wood joists in that area, but everything is too wet/ damp. Dan, I don’t believe a moisture barrier was installed under the concrete. Thanks for the question. I am trying to conclude what the best solution is to control the moisture in my crawl. Your best bet is to have the installer provide the installation guidelines for the polyurea that will be installed. Unfortunately, the deck part of my house is not finished yet (still bare wood) and rain have started to seep through the beam and leaked onto my ready floor. May There are numerous benefits you can derive from laying a weed barrier under a gravel driveway. The ceiling we’re wanting to clad is the bottom of the concrete second floor slab which is 4-years old and has had no moisture issues in the past. Should we cut a hole (core) in order to verify? If you do decide to build a gravel parking pad, it’s still advisable to put a vapor barrier between the ground and the tires. The first thing you need to do is identify if you have a moisture issue and quantify how bad it is. I have opened the garage doors to dry it out and it gets even worse. There are various opinions, but this makes sense to me. However, avoid quick stops, starts and turns. Hi, I live in Houston and have an outdoor patio that I had stained and sealed. W.R. Meadows vapor barrier is called Perminator, it also comes in 10 mil and 15 mil thicknesses. Thanks. Being that this is a very specific, unique question, I am enrolling help from one of my industry counterparts from Stego. the Spillmaster stuff was supposed to prevent mold from coming through yet it seem mold formed right at the seem of the foam and plastic/vapor barrier which is on the living space side of the upper ( the side i walk on) All answers are appreciated. Of course, there’s also the moisture that was in the original concrete mixture. To be effective, a vapor barrier must be installed in a way that prevents any water vapor from getting to the slab. What were the values? obviously we will lay plastic for the entire floor but thought would be double protection under the footing trenches and posts to protect from moisture. Cure with waterproof sheets rather than with water or curing compounds. I’m assuming whoever laid the concrete slab did not put a vapor barrier below it . We purchased our home 4 years ago. I think he is just handing me BS and hiding behind the “moisture level” issue. When utilizing a true vapor retarder such as https://www.stegoindustries.com/stego-wrap-vapor-barriers?hsCtaTracking=d654940e-2168-473c-934d-ed294b689fe3%7C23dd2231-f515-494b-8e7f-b042972bd744 they will have a recommended seam tape and method for application. We can’t afford to keep trying different things. Just ensure the product you choose warrants against hydrostatic pressure. Hello, I am scheduled for concrete pouring already in the next 2 days but this situation concerns me. About a year later the defects showed up again in other boards in the office. For a foundation on slab, install the vapor barrier under the gravel base. Several areas including the center of the 34 ft run have become separated and have quite a lot of play in them. What barrier type is best? After removing the drywall section where the mold was located I found that the OSB was rotted entirely out in several sections. now i am trying to figure out what can i do to have this crawl space safe and not humid I don’t have any access to any drains there so i can’t put a dehumidifier there . The same process was performed. It’s a 15 year old house, but we’ve only been here 4 years, so I don’t know how long this has been an issue. In this article, we will be using the term ‘vapor barrier’. Rigid insulation concrete products like foam sheeting are easily broken and must be used with an extra vapor barrier, plus standard foam or polystyrene concrete insulation does not stop radiant heat … It may not be near the surface, but that doesn’t mean it’s not there. Can you please provide further clarification? In addition, you need a base course of 4″ of clean, graded sand, gravel, crushed stone or slag under 2″ when the slab is below grade unless the existing soil is exempted by the soils report. We had a slab poured in the crawl space below our house this summer. The subfloor will consist of 2 X 6 joists about 1 inch off the slab. Driveway fabric removes the need to use stones larger than one inch in size but do not use rounded stones. I’m I right or am wrong this guy has really screwed me on this the form he built wasn’t strong enough to hold so the top of the form is push out 3 inches from the bottom there a spot in the middle of the slab that holds water this guy thinks he’s going to get paid for this he got the first draw he’s not getting anything else. We are in Florida and would like to know the best method for installing 6 mil poly vapor barrier over our concrete slab, prior to putting down laminate flooring. Thanks Jason! A gravel driveway, even a loose gravel driveway, can be just as long-lasting and durable as one made of asphalt or concrete, if not more so, as long as you know how to properly lay the gravel.In fact, the most significant trait that distinguishes gravel is that it’s more affordable and easier to lay without professional labor or expertise than concrete or asphalt. I am not sure what product was used. Required fields are marked *. Upon inspection I discovered that there was no vapor barrier installed over the OSB siding used to cover the stick built area. Just curious if I’d have issues when the shed gets converted with flooring over the concrete down the road if I don’t use a barrier. I hope this helps. As far as any topical treatment, I would need to moisture test to determine that. Would vinyl planking be a better choice due to fact it would allow for vapor permeability. We haven’t had any leaks so we are assuming it is coming up from the concrete. 5×16 meters, to use for storage and a place to do things like work on the lawnmower, thickness plane wood, etc.. not even 2 weeks later the entire floor started to buckle. And is a vapor barrier under the new to-be-poured concrete needed? I have a contractor that says half of my garage reads a “5” on moisture gauge and wants to lay down a ristoleum vapor barrier for $1850. Thanks for the questions. How would you recommend mediation to resolve issue. What options do I have for vapor barriers/vapor mitigation? sir..i need advice does precast earthing pit need vapor barriers…since this considered as non sturctutral concrete dimension is 30cm x30 cm by 20 cm I need a product that will allow me to put down tile, wood or laminate products. Thanks for the question. What type of moisture barrier should be used and where it should be installed is a subject of debate. Putting this down prior to the tile may help alleviate some, if not all, of the issues. Your email address will not be published. I have a living room that used to be a garage. Great information. It could protect the concrete from freeze-thaw damage by reducing the amount of water it … Please help!! that’s the reason of putting the sheet? 2) Try to find a flooring product that is more “breathable” and/or less moisture sensitive. All the hardwood was ruined. Good luck. Another possibility, or it could be some combination of both, you may be dealing with is some type of condensation issue, but I would think there would be signs on the rest of the floor if that were the case. I have heard different opinions on the use of gravel along with a poly 6mil vapor barrier. !……please help? Obviously, there could be other culprits, but these are the two that come to my head immediately. Didn’t mean to be long winded, I’m still shaking as I type this message. You could be having issues with the moisture in the concrete or some type of dew point/condensation issues. Thanks for the questions. My question is simple for the stick built issues, what is the best and most economical way to replace the failing OSB and what is the best vapor barrier to use over it when it is replaced. I hope this helps. I have had it “fixed” several times and each time it all comes back. I also heard that that there is a moisture retarder/barrier that is like a primer that I can just “paint” on top of the concrete (it’s usually colored pink or purple). The gravel also creates a drain pad which allows any ground moisture and gasses to dissipate. We were looking at a lumber liquidator barrier with pre-applied adhesive and would possibly glue the boards in the area where the runs are greater than 27 feet… Cracks in the sidewalk sprout weeds in April! It might be worth investigating yourself or having someone out to evaluate. You might need an even thicker barrier though if you’re covering material with sharp angles. I used Healthier Choice Spillmaster carpet padding under my carpet. Hi Jason, our garage is approximately 12 years old. Size is 670 so ft. Also, would you see a need for wire mesh in this situation? Also, in some of the inquiries I read about smells, and radon. • Vapor semi-permeable: 10 perms or less and greater than 1.0 perm The adhesive was supposed to be a “2 in 1” adhesive/vapor barrier product. Hi, I’m building a wood framed shed 12 x 12, or 10 x 12 with a concrete floor. They aren’t the only game out there, but it is a place to start. I don’t think I should proceed with the pouring of my radiant concrete slab given this situation. It could protect the concrete from freeze-thaw damage by reducing the amount of water it absorbs from the wet subgrade. Please help. Another solution is the new. The front and one side of the shed will not have walls. Is there something I need to be aware of and watching for in having a concrete floor as my flooring? Can you help me please? Thanks for the question. The “planks” of plywood will use the width of a penny for spacers and using a combination of adhesive and concrete nails to secure. However, the vapor barrier under the slab must have a lower degree of permeance than the flooring (or floor covering) above the slab. I had someone come out to test for moisture and they found “pockets” of high moisture throughout the house wherever the wood floor shows the defects. It makes me wonder if that may potentially be a perfect environment for mold growth. I am working on a project and the exiting mat slab is maintained and will have a new foundation next to it. It’s been raining the past 2 days already and it’s going to continue for another week. – Joe. I plan to install Luxury Vinyl planks with cork backing everywhere, but do not want to install a crinkly underlayment/moisture barrier. A couple years ago I put up another building adjacent to the old one with the floor being 4″ higher than the old building, with the intent on someday pouring a new floor in the old building to match floor levels. Does anyone know what that is? Put the boards on the ground in such a way that the longer (4 inch) side is vertical. If the basement slab was poured directly on the ground, rather on a true vapor barrier, then the ground underneath the slab will always be ‘in play’, and the moisture in the ground below will always want to move upward to the slab’s surface. Now we are considering putting some type of barrier between the two, and are toggling between the mvb moisture mitigation product and a moisture barrier underlayment beneath the vinyl. Instead of going back and forth on this (I have questions), why don’t you just give me a call: Monday-Friday 7:30am-4:00pm at 800-634-9961 X235. Why A Plastic Vapor Barrier Under Concrete Slab Mondays With. I’m going to start building, and vapor barrier doesn’t come in sheets as wide as the house, so I’m getting the idea that the sections/layers should be sealed together with some sort of exterior silicone stuff? What to Do When You Find an Old Wet Concrete Slab, How to Prepare a Concrete Floor for Coatings, Best Conditions for Faster Drying Concrete Times. Due to expenses of resident turnover, they decided to remove carpet/pad/tack and replace with sheet vinyl everywhere excluding Bedrooms, on the first floor for each of the properties. I rather suspect that they would have specifications regarding the acceptable levels of slab moisture before you could actually use their products for an application. 3. I live in Miami, FL bought a two story 1974 townhouse last August 2015. A concrete vapor barrier is simply a sheet of polyethylene plastic (Visqueen) placed directly on top of the sub-grade before the concrete floor or slab is poured to help keep moisture from the soil from passing up through the concrete. Also, do you have any recommendations on if you’d suggest laying down a subfloor before installing the flooring? You should be able to find some type of geotechnical service in your area that can perform a core sample test of the garage floor. A 6-mil (0.006 inch; 152 µm) polyethylene or approved vapor retarder with joints lapped not less than 6 inches (152 mm) shall be placed between the concrete floor slab and the base course or the prepared subgrade where no base course exists.. In a small 5 x 5 toilet room in the master bath, we took up clay tile, In order to tile the whole bathroom Including this separate toilet room with matching tile instead of re-installing carpet. I will assume cosmetic based on how you described it. my biggest question is CAN I SUCCESSFULLY INSTALL CARPET IN MY BASEMENT WITHOUT THE OCCURRENCE OF MOISTURE AND/OR MOLD? Upon further investigation I found that the concrete walled sections of the foundation were covered with 1/2″ plywood over top of some type of other material and the plywood was covered on the outside with a latice wood material, purpose unknown to me. This water can move up through the soil and come into contact with the bottom of a concrete floor via capillary action. Say 12″ X 12″ tile or a breathable carpet. This may help you understand better. If you’ve ever had a problem with a basement floor (or any concrete floor), you know the kind of damage that too much moisture can cause. What are the solutions? Thanks for the question. I cleared efforescent and dried floor. Thanks for the comment. I think if you were to read my other articles and/or view my video’s you would see my overarching opinion that concrete loves water, but it’s the flooring finishes that we use that don’t. If you are going to seal an exterior slab, find a sealer that transmits water vapor (breathes). Every year I weed (fortunately, if you catch weeds before they seed in our dry climate, this chore diminishes), but the weed barrier really does … He feels we need to consult with a foundation expert. Have already spent $5,000 trying to solve this issue. Thanks for the question. I have had people suggest diamond grading it and putting stamped overlay down and then I have had people say it will just come back up through that too because there no vapor barrier under my patio. i recently started a renovation and i decided i wanted to pour cement over the whole crawl space.