In this Limestone Analysis you will find several different finishes in limestone block: Masons who work on commercial construction are occasionally required to apply stone to the work. It's suitable for caps, lintels, coping, and moldings as well as veneer over other masonry. Counter tops are commonly made of limestone.
Smooth Finish: recognized as the standard finish. It looks and feels smooth, and can be produced by a variety of machines.
Diamond Gang Sawed: is a smooth finish which may contain some parallel markings and scratches. The direction of these markings can be either horizontal or vertical. You can specify which way you want the markings to run.
Chat Sawed Finish: is a medium rough finish. It's produced by sawing with a coarse abrasive containing some metallic minerals which may add permanent brown tones to the natural color variations. This finish may contain parallel saw marks.
Shot Sawed Finish: is a coarse uneven finish ranging from a pebbled surface to one ripped with irregular parallel horizontal or vertical grooves. Steel shot used in the sawing process produces the random markings. The shot markings are uncontrolled and the joint lines may show deviations in the sawn face. Rust stains from the steel shot can cause additional color tones.
Where is Limestone found
When suppliers are making the stone they are continually doing an Analysis on it so that they get it as close as possible to the real thing.
Cleaning Natural Limestone Analysis
Natural limestone is wet when it's quarried. This moisture called quarry sap, contains various amounts of organic and chemical matter. Gray stone usually has more moisture than buff. As the stone dries and stabilizes, it seasons, the wetter the ground, the longer it takes to season. Slabs season faster than blocks.
If you are
on a natural limestone project, your contract may require you to buy the stone in time for it to season and stabilize before you install it. Sometimes a quarry may have to ship unseasoned stone. This stone may very in color for several months, or even a year. You cannot make the stone season faster, or you will weaken it's characteristics. Also do not add sealers or water repellents of any kind during curing process.
In this Limestone Analysis masonryworktools.com has researched extensively to supply you with quality statistics on how to best take care of limestone, both natural and cultured. Limestone delivered to the job site may have slush, planer dust, and road dirt on it, it's best to wash and scrub stones to get rid of the debris so the mortar and sealer will stick properly.
Sometimes brown (alkali) stain will show up on new construction. This problem is second only to mortar smears. Brown stain occurs when highly alkaline water contacts the stone backs and beds. To avoid this problem, avoid these situations:
1. Window openings, top of walls where rain, or snow can get between structure and stone, this will soak into the stone and try to come out the surface, leaving stains on the face of the stone.
2. Wash from a concrete pour leaking down into the cavities or otherwise getting behind installed limestone.
3. Limestone used as a concrete form panel.
4. Sidewalks poured against installed limestone.
Brown stain can be especially troublesome on paving, curbing, steps or platforms if they are not sealed or damp proofed. Ground moisture can go into these stones. Mortar used above grade doesn't usually contain enough water to make an intense stain. When mortar is the culprit, the stain is usually quite light colored and limited to the area of the joints.
During our Limestone Analysis we have found that walls that are slushed or grouted are candidates for stain. When you can't prevent stains you will have to try and remove them.
Nothing you can do will stop recurring brown stain caused by alkali leached from cement when wall is wet. Any treatment is wasted effort unless you can stop all moisture from getting the wall first. Good news is that as the wall dries, natural weathering will usually remove the stain without a trace.