Concrete Crack Measurement Tools' title='Concrete Crack Measurement Tools' />GATE Coaching at Eii is Top Ranked GATE Coaching Institute with Highest Results. Eii offers best GATE, IES and PSUs Coaching in Delhi. This is how to make an excellent excuse for driving a lag bolt into your wall, the Concrete Lightbulb Wall Hook. Functional yet sylish, it gives a nice industrial. Elasticity. The modulus of elasticity of concrete is a function of the modulus of elasticity of the aggregates and the cement matrix and their relative proportions. Contractors Guide to Efflorescence The Concrete Network. Efflorescence is a fact of life with most concrete. We are hearing more about efflorescence related issues because of the popularity of stained floors. As the trend to have exposed concrete floors grows, the industry is struggling with the problem of unsightly efflorescence, especially when it is trapped under a film forming sealer. This is not to say that exterior decorative concrete is immune from efflorescence issues, but problems with interior floors pose a greater challenge and are the focus of this discussion. New Concrete Admixture Puts an End to Efflorescence. This article is meant to be a common sense overview of the major efflorescence issues. We will suggest realistic preventative measures to control the conditions that encourage efflorescence and we will offer remedial suggestions. We will offer useful explanations of this complex phenomenon in practical terms without a lengthy detailed chemical analysis. Decorative contractors usually get the first phone call when efflorescence shows up on a stained floor. Many things may have contributed to a particular efflorescence plagued project, the least of which may be the work performed by the stain contractor who in most cases is unaware of the preexisting conditions that caused the efflorescence. Stain contractors, concrete finishers, builders, general contractors, the design community and owners are all affected by issues related to efflorescence. We hope this discussion clarifies some of the issues so that efflorescence is better understood and the appropriate measures are taken to prevent its occurrence. The costs associated with efflorescence prevention are minimal when compared to the cost and inconvenience of the remedies, especially when the space is occupied. Efflorescence in itself is not a health problem although it might indicate moisture levels sufficient to support mold. Efflorescence is not a structural issue. It is an aesthetic issue, an issue we would all like to avoid. Definition of Efflorescence Efflorescence is the white powdery substance on the surfaces of unsealed concrete and the white blush seen with sealed floors. Efflorescence is caused by vapor migrating through the slab bringing soluble salts to the surface of the concrete. Efflorescence is normally worn off or washed away on unsealed concrete surfaces. Large/910393__1.jpg' alt='Concrete Crack Measurement Tools' title='Concrete Crack Measurement Tools' />In stubborn cases, a mild acid rinse or even a light sandblasting may be necessary. Efflorescence that becomes trapped under sealer is unsightly and is even more conspicuous on darker floors. In worst case scenarios where the vapor cannot pass through the top coat, a urethane andor an epoxy for instance, hydrostatic pressure can build to create water blisters indicating delamination of the top coat from the concrete. Blistering is rarely seen with acrylics. Acrylic sealers allow the vapor to pass through, but the salt deposits remain behind creating the unsightly blush that prompts owners to call the stain contractor. Contributing Factors Efflorescence requires the movement of moisture. Without moisture movement there would be no efflorescence on the surface to create the problem. Unfortunately, too many finishers non ACI Certified Finishers routinely introduce large amounts of unnecessary water of convenience to the mix in order to facilitate concrete placement. Primary efflorescence is caused by the water in the concrete evaporating from the slab leaving behind the soluble salts on the concrete surface. The fact that these salts are actually more soluble in colder temperatures coupled with increased bleed water in cold weather increases the likelihood of efflorescence showing up after winter concrete placement. Contributing further to efflorescence with cold weather pours is the use of calcium chloride to accelerate the set time. High slump concrete and the addition of calcium chloride are major contributors to efflorescence. Secondary efflorescence is often described as water coming from underneath the slab or water that is introduced from the surface. Likely sources of secondary efflorescence would be a saturated base material, an improperly drained site or excessive amounts of water used by the decorative flooring contractor during his cleaning process rinsing off the acid stain residue, for example. When extra mix water and extra soluble salts from calcium chloride are added to concrete placed in cool weather followed by more water from the decorative processes, some degree of efflorescing is bound to occur. Testing for Vapor Transmission Even if some answers are provided it behooves the contractor to do some independent fact finding to determine the current vapor transmission rate VTR. Probably the oldest test method is the Plastic Sheet Test ASTM D 4. X 1. 8 sheet of poly and checking 1. Both are indications of vapor transmission. Another surface moisture test is The Calcium Chloride Test which quantifies the rate of vapor transmission. This is a covered dish that is weighed before and after a twenty four hour period. Both are cost effective measures in determining whether vapor is active. A note of caution when using these testing methods. When the atmospheric conditions are similar to the slab conditions the tests might not indicate significant vapor transmission because movement happens when the ambient conditions differ from the slab conditions. Moisture migrates and moves toward cool temperatures. Vapor emissions migrate and move toward heat. Imagine the consequences of the following unpleasant, but very real scenario. HVAC causing vapor in the slab to move towards the warmth or the lower humidity of the conditioned space bringing the whitish minerals with it. If the sealer is acrylic the vapor will pass through leaving the efflorescence. If urethanes or epoxies are on the floor, hydrostatic pressure may build and possibly cause delamination. Efflorescence can occur months or even years after the contractor has left the job due to circumstances similar to those just described or from seasonal ground water seeping under the slab. Testing the surface may not be enough to guarantee an efflorescence free project for years to come. It is important to determine the source and the rate of vapor transmission before prescribing a remedy. Autoit Open Serial Port. Determine ahead of time if efflorescence is a likely problem waiting to happen on your project Are there signs of efflorescence now Is the property properly drained Does surface water run towards the foundationIs there a French drain system How old is the slab, what time of year was it poured Was the concrete placed on a saturated sub gradeWas the concrete placed directly on a vapor retarder Was a granular material placed over the vapor retarder vapor barrier being the outdated term and was the base saturated If a vapor retarder was used, was it carefully taped at penetrations, around the plumbing, for instanceDid the mix design include fly ash Was a waterproofing admixture usedWas calcium chloride used How much water of convenience was added to the concrete Was a curing compound or liquid densifier applied Answers to at least some of these questions can give a decorative contractor a heads up before wading into a project completely uninformed and unprepared. More accurate testing technology such as the 1,0. Protimeter Moisture Measurement System ASTM Standard F 2. Two non invasive hand held devices using similar technology are the Aquant 3. Tramex Concrete Encounter Moisture Meter 4. Basement Flooring How To Insulate A Concrete Floor. By Todd Fratzel on Basements, Foundations, Insulation. Insulating Concrete Floors. If you live in a cold climate then youre no stranger to cold concrete floors in the winter. If youre planning on finishing a basement or portion of your home that has a concrete floor then it may be a good idea to insulate it before installing basement flooring. Concrete floors are cold and full of moisture that can be a long term maintenance problem. Methods To Insulate A Concrete Floor. There are numerous methods for insulating concrete floors and slabs. The method that you chose really depends on cost and available headroom. If youre finishing a basement most building codes require a minimum finished head room of 7 6. So any choice in the insulated sub floor must account for that minimum height including the finished ceiling construction. The following are two methods that weve used in the past with great success. Insulated Sub Floor Panels. There are numerous products being sold today that are typically a combination of rigid foam insulation and some type of sub floor material like OSB. There are quite a few of them on the market including Barricade Subfloor Tiles. The subfloor tiles are really great for folks with little DIY experience and clearance issues as they provide one of the thinnest insulated options. Insulated Sub Floor. If youve got adequate headroom and few interferences then this is the method that we like best. This method works great if you dont have many doors and you can deal with the higher sub floor at the stairs. The method is quite simple consisting of a layer of foam board insulation, sleepers and a plywood sub floor see diagram above. First you need to be sure the floor is clean. Evermotion Rapidshare'>Evermotion Rapidshare. Be sure to fix any problems in the concrete floor such as cracks, spalls and water problems. Install a layer of rigid foam board insulation such as Styrofoam Tongue and Groove or Styrofoam Brand Highload 4. We recommend at least 1 inch of foam board. Use a good quality foam board adhesive to adhere the foam to the concrete. If youre interested in learning more about foam board insulating properties then check out our article on R Values Of Foam Board Insulation. Seal all the seams of the foam board insulation. We recommend you tape the seams with Tyvek or similar tape. You can seal along the walls with spray foam from a can Great Stuff or similar. Install pressure treated sleepers. We recommend using 34 thick pressure treated decking. Use foam board adhesive along the bottom of the sleepers and also attach the sleepers to the concrete using masonry nails or a powder actuated nailer. Install a layer of 34 inch tongue and groove Advan. Nemesis Of The Roman Empire Crack. Tech or other sub floor material. We recommend you screw the sub floor to the sleepers using stainless steel screws and sub floor adhesive as well. We really recommend you consider using Advan. Tech because of its excellent properties in damp environments. Finally install your finish flooring. You can install any type of flooring at this point because of the sturdy sub floor. Final Thoughts On Insulating A Concrete Floor. The only issue to watch out for in this situation is the height. Youll most likely end up with 1 inch of foam board, 34 of an inch sleepers and 34 of an inch for the sub floor for a total of 2 12 inches. This will most likely require doors to be lifted and stairs to be reconfigured. However, youll have a very warm comfortable floor and a whole lot less moisture in your basement. Want To Hire A Professional If youre feeling a bit overwhelmed by a full basement remodel then you may want to consider hiring a contractor. A good place to start is using industry proven contractor referral companies. Company like Service. Magic offer a great referral service. Just follow the next link.