Method for matching surface texture and color of concrete roofing tiles

Abstract

A method for changing the color and texture of ceramic roofing tiles, including the steps of identifying a damaged tile to be replaced, cleaning the damaged tile, optically measuring the damaged tile to yield a color determination, and selecting a replacement tile of the same shape and general color, immersing the replacement tile in a quantity of acid, removing the tile from the acid after a first predetermined length of time has passed to yield an acid-treated replacement tile, rinsing the acid-treated replacement tile to remove remaining acid, measuring the color of the acid-treated replacement tile, and washing the acid-treated replacement tile.

We claim: 
     
         1 . A method for changing the color and texture of ceramic roofing tiles, comprising:
 a) identifying a damaged tile to be replaced;   b) cleaning the damaged tile;   c) optically measuring the damaged tile to yield a color determination;   d) selecting a replacement tile of the same shape and general color;   e) stripping sealant from the replacement tile;   f) immersing the replacement tile in a quantity of nitric acid;   g) removing the tile from the acid after a first predetermined length of time has passed to yield an acid-treated replacement tile;   h) rinsing the acid-treated replacement tile to remove remaining acid;   i) drying the tile; and   j) measuring the color of the acid-treated replacement tile.   
     
     
         2 . The method of  claim 1  and further comprising:
 k) after b) and before c), applying citric acid to an unweathered portion of the damaged tile. 
 
     
     
         3 . The method of  claim 1  and further comprising:
 l) after i) and before j), adjusting the color of the acid-treated replacement tiles via immersion in a second acid for a second predetermined period of time; wherein the second acid is selected from the group consisting of sulfuric acid and hydrochloric acid; and wherein the second acid has a concentration of between 0.5N and 1.5N. 
 
     
     
         4 . The method of  claim 1  wherein the first predetermined period of time is one hour and wherein the nitric acid has a concentration of between 0.5N and 1.5N. 
     
     
         5 . The method of  claim 1  wherein during step c), the damaged tile is assigned first L*, a*, and b* values; and wherein during step i), the acid-treated replacement tile is assigned second L*, a*, and b* values. 
     
     
         6 . The method of  claim 5  and further comprising the step of:
 l) comparing first and second sets of L*, a*, and b* values. 
 
     
     
         7 . A color matched tile for replacing a weathered tile, comprising:
 an acid-etched exterior portion; and   an interior portion disposed beneath the acid-etched exterior portion;   wherein the acid-etched exterior portion has substantially the same L*, a*, and b* values as does the weathered tile.   
     
     
         8 . The color matched tile of  claim 7  wherein the acid-etched tile is substantially free of sealant. 
     
     
         9 . The color matched tile of  claim 7  wherein the acid-etched tile has substantially the same surface texture as the weathered tile. 
     
     
         10 . A process for matching the color and texture of a new ceramic roofing tile to a weathered tile, comprising:
 m) identifying a weathered tile to be replaced;   n) cleaning the weathered tile;   o) treating an unweathered portion of the weathered tile with citric acid;   p) optically measuring the weathered tile to yield a color determination;   q) selecting a replacement tile of the same shape as the unweathered tile and the same color as the unweathered portion of the weathered tile;   r) stripping sealant from the replacement tile;   s) immersing the replacement tile in a bath of nitric acid;   t) removing the tile from the bath after a first predetermined period of time to yield an acid-treated replacement tile;   u) removing residual acid from the acid-treated replacement tile;   v) adjusting the color of the acid-treated replacement tiles via immersion in a second acid for a second predetermined period of time;   w) drying the acid-treated replacement tile; and   x) measuring the color of the acid-treated replacement tile;   wherein the first predetermined period of time is one hour;   wherein the nitric acid has a concentration of between 0.5N and 1.5N;   wherein the second acid is selected from the group consisting of sulfuric acid and hydrochloric acid; and   wherein the second acid has a concentration of between 0.5N and 1.5N.   
     
     
         11 . The method of  claim 10  wherein during step p), the weathered tile is assigned first L*, a*, and b* values; and wherein during step x), the acid-treated replacement tile is assigned second L*, a*, and b* values. 
     
     
         12 . The method of  claim 11  and further comprising the step of:
 y) comparing first and second sets of L*, a*, and b* values. 
 
     
     
         13 . The method of  claim 10  wherein the step s) has a duration of one hour.