Abstract:
A method of forming an integrated cementatious floor topping at a site, comprising the steps of: assessing the site and preparing a sampling of materials and colors, which are blended and poured to meet a client&#39;s specification; prepping the site having a subsurface to accept and to allow a comprehensive bond with a concrete mixture to be poured; combining additives to the concrete mixture and pouring the mixture; troweling and then curing the mixture surface; beginning polishing the surface followed by densifier application and drying; and resuming polishing to yield a finished topping ranging from 2 to ¼ inches thick.

Description:
[0001]    This application claims priority from U.S. Provisional Application No. 61/354,122, filed 11 Jun. 2010, whose disclosure is incorporated herein by reference. 
     
    
     FIELD AND BACKGROUND OF THE INVENTION 
       [0002]    The current invention is generally related to concrete flooring and specifically to a cementatious floor topping having a thin, strong, maintenance-friendly smooth surface finish and a method of producing the same as a continuous surface. 
         [0003]    In producing concrete flooring today, a typical sequence of activities as known in the art is: pouring a wet concrete mixture into a formed area; and then screeding; floating; and troweling the concrete surface to produce a flat surface, all as described in more detail hereinbelow. 
         [0004]    Typically, the first step of producing such flooring is by pouring/depositing concrete into a forming substrate, which may be either a corrugated steel sheet or earth covered with crushed gravel and perhaps a suitable vapor barrier—all as known in the art. The concrete mixture is then screeded with a straight edge after it is poured, and then floated when the concrete hardens. The next step is to float the concrete surface, as known in the art. The purpose of the float operation is to densify the concrete and to prevent the occurrence of voids. Typically, a flat floating tool such as a “bull float” is used for floating. 
         [0005]    A standard concrete floor may have color or dye mix so as to color the finished floor. In the traditional technique an entire floor is commonly formed as a unit without the use of intermediate forms controlling the height or thickness of the floor and thereby creating what is known as a monolithic slab. 
         [0006]    The next step of troweling is a standard and preferred technique commonly used today as the finishing operation on a poured concrete floor. 
         [0007]    An example of prior art reflecting the techniques described hereinabove is U.S. Pat. No. 4,281,496 to Danielsson, whose disclosure is incorporated herein by reference. Danielsson describes a method for forming a concrete floor as a monolithic unit wherein wet concrete mix is deposited and screeded to achieve a generally uniform thickness of concrete with the aggregate being densified or settled to produce a thin upper layer formed substantially from sand and cement, thereafter floating the concrete to substantially remove surface irregularities, and then grinding the upper surface of the concrete floor after it has hardened to produce a d flat surface having a “sanded” finish. 
         [0008]    In some cases, additional surface operations are performed to the concrete floor to yield additional effects, such as ornamental/decorative effects or additional surface features. 
         [0009]    Palermo et al., in U.S. Pat. No. 7,591,967, whose disclosure is incorporated herein by reference, describes a method for forming a concrete floor as a monolithic unit, wherein a wet concrete mix is deposited and worked to achieve a generally uniform flatness of concrete and adding to the top layer thereof a decorative aggregate material. Subsequently, the surface of the concrete is worked, allowed to partially cure and then ground and polished to substantially remove surface irregularities and reveal the decorative aggregate. The floor surface may then be coated with a sealant to achieve a terrazzo-like appearance. 
         [0010]    Prior art techniques used to creating concrete floors and then finishing them have also been applied to repairing the surfaces of existing concrete floors and/or refinishing them and the surfaces are commonly referred to as “floor toppings”. 
         [0011]    All prior art methods of concrete floor toppings involve additional time, materials, and labor to achieve good results. There is therefore a need to produce a thin, smooth, high quality and strong concrete surface/floor topping which takes significantly less time, material, labor, and resultantly reduced overall costs to produce. 
       SUMMARY OF THE INVENTION 
       [0012]    According to the teachings of the present invention there is provided a method of forming an integrated cementatious floor topping at a site, comprising the steps of: assessing the site and preparing a sampling of materials and colors, which are blended and poured to meet a client&#39;s specification; prepping the site having a subsurface to accept and to allow a comprehensive bond with a concrete mixture to be poured; combining additives to the concrete mixture and pouring the mixture; troweling and then curing the mixture surface; beginning polishing the surface followed by densifier application and drying; and resuming polishing to yield a finished topping ranging from 2 to ¼ inches thick. 
         [0013]    Preferably, the floor topping is formed without having the need to remove a current slab. Typically, the floor topping is formed without having the need to expose aggregate in the process of polishing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The invention is herein described, by way of example only, with reference to the accompanying drawing, wherein: 
           [0015]      FIG. 1  is a flow chart showing the steps of a method of installing a floor topping, in accordance with an embodiment of the current invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0016]    Embodiments of the current invention are generally related to concrete flooring and specifically to concrete flooring having a thin, strong, maintenance-friendly smooth surface finish and a method of producing the same as a continuous surface. In one embodiment of the current invention, as described in detailed hereinbelow a progressive polishing operation on a cured ovelayment produces the unexpected results of a floor surface/floor topping having a unique stone-like appearance with the advantage of significantly less time, material, labor and accordingly reduced overall costs. 
         [0017]    The advantages noted hereinabove are due primarily to the fact that embodiments of the current invention enable a stronger and thinner topping to be installed/produced in comparison to those of the prior art, as is further indicated hereinbelow. 
         [0018]    Reference is currently made to  FIG. 1 , which is a flow chart showing the steps of a method of installing a floor topping  10 , in accordance with an embodiment of the current invention. Step  20 , assessment, comprises an assessment of the site to be topped to prepare a sampling of materials and colors, which can be blended and poured to meet a client&#39;s specification. In the assessment step, the client is informed of different flooring options, including but not limited to concrete toppings. Once the client specifies his preference for color/colors and finish, samples may be prepared to verify the client&#39;s tastes and to obtain his sign off on the entire flooring job. 
         [0019]    Following assessment  20 , in Step  25 , prepping, an existing flooring and/or subsurface (collectively referred hereinbelow as “subsurface”) is prepped (i.e. “prepared”) to accept and allow a comprehensive bond with the concrete mixture to be poured, as known in the art. In Step  30 , combine additives, a combination of additives is added to the concrete mixture to reduce shrinkage, inhibit cracking, and to reduce the amount of water used, while accelerating the curing process, as described hereinbelow. 
         [0020]    The concrete mixture is prepared by mixing additives as described hereinbelow. Note that the quantities of additives may be mixed in a similar ratio to scale up or scale down the size of the topping, with the following quantities being appropriate for a floor topping having a surface area of approximately 100 square feet and a thickness of approximately 0.5 inches. 
         [0021]    Mix approximately 25 gallons of sand to 1 standard bag of cement, approximately: 6 quarts of hydro sand, 6 quarts of silica flour, 3 ounces of micro fibers, 8 ounces of plasticizer, 8 ounces of crack reducer, 8 ounces of accelerator, 6 ounces of water repellent, and 1 gallon of polymers diluted into approximately 4 gallons total. The quantities noted hereinabove are approximate and they may each be changed, by about +/−20%. Color, aggregates, and/or inlays can additionally be added per job specifications and requirements at this point in step  30 . 
         [0022]    After additives are combined the topping is installed, by pouring the concrete mixture, all in Step  30 . and the in Step  32 , troweling, hand troweling is first performed for hard-to-reach and angled areas. Troweling machines can then be brought in to work main floor areas. A continuation of troweling the floor while increasing the speed of the machine may be done to burnish the floor to achieve the final layer that is to be polished. 
         [0023]    In prior art topping preparation, a typical next step would be to grind the topping. This costly procedure (i.e. use of diamond blades, manpower, and time) are obviated in embodiments of the current invention and represent a significant cost and time savings. At this point, the next step is Step  35 , curing process wherein the poured and troweled concrete surface cures. 
         [0024]    The curing process includes the concrete “resting”, which means allowing the troweled poured concrete to solidify and strengthen, as known in the art. Typically, curing takes 24-72 hours. 
         [0025]    Step  40 , begin polishing, follows the curing process. Polishing is typically prepared using diamond loaded pads, as known in the art. Initially a low grit number, such as 400 is used and a higher grit of 800 normally follows, as known in the art. However, before the 800 grit pad is used, Step  45 , densifier application, is when a densifier is applied to the surface of the topping. The densifier serves to close the pores of the concrete and leaves a harder surface. 
         [0026]    The next step is Step  50 , drying, when the densifier dries. In Step  55 , resume polishing, 800 grit polishing commences. Depending on the level of polishing desired, higher grit polishing (eg. 1600 and 3000) can continue, as part of step  55 , until the desired surface finish is obtained. 
         [0027]    Once the desired finish (matte, semi-gloss, or high sheen) of the floor has achieved, in step  55 , polishing, buffing pads can be used to finish the process. Buffing/polishing may be performed approximately 24-72 after troweling to close the pores of the cementitious overlayment. (In some cases, buffing may be continued for up to 28 days.) The concrete retains a natural characteristic porosity that promotes the receptivity of liquids and which may yield permanent stains. To mitigate staining, as well as to make the floor dust proof and abrasion resistant, a compound may sprayed or spread over the floor surface. Optionally or additionally, waxes, sealers, and/or epoxy urethanes can be used as desired. 
         [0028]    Embodiments of the present invention provide the ability to produce a concrete floor that can be troweled for a true concrete finish in place of a standard floor, i.e., wood flooring, tile, carpet, etc., without having to demolish an existing sub flooring and pour back concrete. For example, a user can pour concrete to yield a topping thickness ranging from 2 to ¼ inches and more typically from ⅜ to ½ inches and to achieve a true concrete finish. The resultant concrete topping can give the look and feel of a traditional 4-inch thick concrete slab, without having the need to remove the current slab and/or exposing aggregate in the process of polishing a floor—representing a substantial savings in labor, materials, and time. 
         [0029]    Additionally, although it is recommended to commence polishing (step  40 ) 48 or more hours following troweling, embodiments of the current invention enable polishing (step  40 ) to be commenced as early as 24 hours following troweling. 
         [0030]    The topping can have integral coloring throughout and/or embedded objects in it such as glass, metal, or stones. Furthermore, the topping can be machine troweled and polished to a matte finish or a high gloss mirror finish. Concrete topping options can take on a wide variety of choices, can be custom color-blended for different tones by using white or gray cement mix, and the finishes may vary from a sponged or a broomed finish to other polished options. Flooring design can also be achieved, with additional materials being inlaid such as stone, metals, etc. Additional color can be introduced by using dyes, acid stains, or color hardeners, and/or the use of stencils and/or saw cuts can provide more options to the floor. 
         [0031]    In the steps described above, it will be apparent that the use of machines and other equipment, depending upon the size of the floor area, may be preferred. However, embodiments of the present invention include application to smaller areas, and areas in which automated equipment may not be used, for example, along the edges of building or structures. In such situations/applications, the various steps may be completed manually, or by using equipment designed for edge work. For example, the various grinding and polishing systems described are also generally available in smaller or single-head units that may be employed to grind and polish edges and corners of concrete floors. 
         [0032]    Embodiments of the present invention can be used to produce a flooring surface/topping which can be unique to consumer/client preference. Such embodiments can also be used to produce other kinds of interior and exterior surfaces to the preference of a consumer, e.g., countertops, wall coverings, and/or concrete furniture, which may provide a true concrete overlay suitable for machine troweling. 
         [0033]    It will be appreciated that the above descriptions are intended only to serve as examples, and that many other embodiments are possible within the scope of the present invention as defined in the appended claims.