(480) 584-3742 chad@selectinteriorsaz.com
Floor and Surface Preparation 101
Floor prep in the flooring industry can easily be overlooked, especially if it’s a new build. What can be wrong with a new slab, right ? There are several reasons why floor prep will be needed prior to installation. There can be high or low spots, moisture issues or demo crew did a insufficient floor scrape leaving adhesive behind. Those are some of the most common causes.
There are flooring materials and substrates that will require additional prep than others. For example, carpet tile will not require a full skim whereas resilient flooring or sheet vinyl will. However, every surface is to be clean and clear of debris as well as porous for a mechanical bond between flooring adhesive and substrate. Not all substrates are acceptable and will require specific primers as floor preparation.
During the bid process, we are not often granted access to walk the project before existing flooring is removed. We consider these unforeseen conditions, and unable to properly evaluate to include the necessary floor prep quote. Existing flooring may not be removed before a project is sent out for bid or contracts are awarded. Select Interiors will be consistent with our communication to schedule a job walk following demo to access and evaluate the condition and steps deemed necessary. An alternate may be provided based on notes and direction by others.
For each project, we anticipate minor floor prep such as filling in pin holes and minor cracks (less than 5’ long and 1/8” thick). Along with light sweeping as needed. Floor scraping and grinding is excluded. Excessive floor preparation or patchwork is considered an “Extra” to the contract and will be done only with the written consent of the General Contractor or his agent. All “Extras” will be done in this manner. Below are a few examples as each project is unique.
SOLUTIONS
Resilient flooring (VCT, LVT/LVP, Sheet Vinyl) specified? Whenever installing a resilient flooring, providing a full coverage skim coat is best practice. Skim coat is a cementitious product that is used to smooth and repair imperfections of the slab, a thickness of up to 1/16”. Including but not limited to saw joints, cracks, and to level surfaces (excluding self-level). Resilient flooring has the tendency to telegraph surfaces adhered to, some surface faces will have a glossier appearance paired with lighting will have a unwanted ripple effect. Typical substrate tolerance for carpet, resilient, laminate and wood flooring is 3/16 inches over 10 feet. Manufactures may have other tolerances to follow.
High or low spots?First step would to figure where and how often these appear. Using a laser 10 foot level, the measurements are mapped on the drawing. If high spots are ½” or more, we suggest grinding those down, if less than ½” another option would be self-level. Self-level would also be used for the low spots thus bringing the floor to one continuous level surface. Patching in low spots with patch and skim is another practice. Each of these methods have different costs associated along with overall square footage being a factor.
Left over adhesive from flooring and overspray?Why is this a problem? Many if not most flooring and adhesive manufactures require the floor to be free of existing adhesives so their product can mechanically bond as it is intended. The remaining adhesive does not provide the porosity needed and will need to be removed. There are two solutions for this ! One is to encapsulate the adhesive using the skim coat method. This is preferable should the scheduled flooring be resilient. This will also aid in scheduling and budgeting. The second is to grind the floor to remove the adhesive. This can be a great option, but also be impactful to lower levels depending on the work hours.
When it comes to overspray, this includes drywall mud, texturing and paint. Mud and texture will leave behind hardened clumps that we cannot install over. Typically this is the responsibility of that trade and general contractor to keep the space clean. Paint can sometimes be an oil base which will not allow the adhesive to properly bond and cure leaving to failure. Our solution to these situations is to scrape or grind if necessary.
Polished or sealed concrete substrate? When the surfaces have a shiny appearance, that is a red flag for flooring installers. Shiny equates to a topical sealer that will not allow the adhesives to mechanically bond as intended. Most common solution is to sand the floors allowing the concrete to be porous again. If noise and dust is a factor, we can also use a primer with a grit texture.
High RH levels and moisture?RH stands for relative humidity, the amount of water vapor present. Our field will drill a core in the concrete slab and insert a RH probe. After 24 hours, the results will be determined if additional floor preparation and moisture barrier is needed to encapsulate the moisture to not disturb the flooring. Concrete slabs should have a vapor retarder to prevent moisture from below penetrating up, depending on age of building.
Applying a moisture barrier such as an epoxy-based system will not permit moisture from escaping through. The process is extensive which adds to cost, however, allows for a more permanent solution. Step 1 is to grind the floor allowing it to be porous for accepting the epoxy barrier. Step 2 is to apply the epoxy barrier allowing it to cure. Step 3 is applying a self-leveling system providing a new substrate for adhesives to mechanically bond as intended.
Additional solutions is reselecting products and adhesives that will sustain the moisture up beyond the RH percentage. However, products such as carpet, resilient flooring and adhesives also has their limits before voiding warranty. Example 1, RH is 98%, Manufacture X has a carpet tile that will sustain 99% RH if used with their high moisture adhesive. Example 2, RH is 98% Manufacture ABC has a product that will sustain 99% RH, but they don’t have an adhesive that will, therefore we can not use product from Manufacture ABC.
Although typically seen for use on grade with a floating floor or hardwood floor, an underlayment may also be used. The underlayment made of polyethylene or polypropylene is a roll which will prevent the moisture from impacting the floating floor such as warp or delamination of the product. Other manufacturers may only allow their moisture mitigation systems which will vary in application.
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