Maintenance & Restoration

CLEANING & GENERAL MAINTENACE OF STONEWORK
All stonework is generally best cleaned of normal dust build up using warm water and a mild detergent on a regular basis.

Cleaning frequency and method are best trialed and set to suit individual  situations depending on surface finish, volume of traffic, amount of dirt or dust accumulated in a given time etc.

Granite
Due to the hardness of granite, little maintenance is required.

Polished granite
> Granite cladding on external walls may only need to be wiped down when the windows are cleaned.
> In foyers and lift lobbies, a wash with mild non-ionic detergent followed by clean water will suffice.
> Don't use abrasive cleaning products, steelwool or pads, as these will scratch the surface if used vigorously, avoid using silicone based cleaning pads as they may leave a coating, making the surface impermeable for further  cleaning.

Exfoliated or Sawn Finished Granite
> These finishes will not repel contaminates, such as coffee or soft drinks, like a polished finish will. Instead, it will absorb then leave a stain.
> Pressure spraying with detergent is suggested to remove the stains in an outdoor setting.
> If indoors, the only solution is hand washing with detergent.
> If staining remains, cleaning methods involving a poultice or complete replacement are the only solutions.
>At all times test the cleaning method in a remote area first.

Marble
In all marble cleaning operations, the use of clean, hot water is recommended  for the best and most efficient results.

Polished Marble
> A non-precipitating, non-acidic soluble cleaner, containing no grease, lye or other corrosive filters is recommended.
> The cleaner should rinse freely, even in hard water, not leave a greasy or slippery film that will catch and hold dirt and discolour; as well as not  scratch.
> Wet the marble thoroughly with clean, clear hot water.
> Wash the surface with a solution of the soluble cleaner made in accordance with the manufacturer's directions.
> Wash from the bottom up in small, overlapping sections.
> Rinse each time with clean water using soft cloths.
> Use soft cloths or clean chamois to dry the surface and prevent streaking.

Honed Marble
> Steam cleaning of marble exteriors is satisfactory if no harmful acid  cleaners or injurious alkalies are used.
> Repointing to make joints watertight if needed should be undertaken along  with surface cleaning.
 
Marble flooring
> A mildly alkaline abrasive cleaner that contains no caustic or harsh fillers is recommended.
> Avoid all types of coarse or hard abrasives.
> Sweep marble and remove all grit, dirt, etc.
> Wet the marble thoroughly first with clean, clear hot water.
> Sprinkle abrasive cleaner on a wet fibre brush and scrub the marble.
> Rinse thoroughly and wipe dry to avoid streaking. Always use clean water for rinsing and frequently change the washing water.

Sandstone
> Sandstone is prone to picking up dirt, dust oils, greases and the like from  both direct contact and from the atmosphere.
> Due to it's porousness, it will absorb these contaminants, not only causing  staining, but also promoting the growth of algae.
> Sealants are not recommended as they stop moisture coming through the  surface of the stone, causing spalling.
> When washing sandstone, wash with warm water and soft brush only.
> The frequency of washing is up to the owner but it should be recognised that cleaning washes out the bonding agents or cementious material in the sandstone.
> In the long term (30-50 years), the results will be discernible so that the  stone will be clean but obviously well worn.

IN GENERAL

PAVING
For internal polished and honed we recommend a mop down daily with a detergent which doesn't require excessive rinsing off to stop build up and yellowing.

The same principle applies for internal exfoliated paving although the frequency of mopping should be decreased to once or twice per week and on other nights the surface should be vacuumed of dust using a soft pliable brush fitting to ensure material is picked up from the even surface.

External paving should be cleaned using the same principles as above on a  regular basis although it is not unusual for little cleaning to be done and a regular fortnightly or monthly clean using higher than normal water pressure to be carried out.

Again frequency of cleaning is required to be assessed on a case by case basis.

External paving can benefit from a mild acid wash, as needed, to remove any  dirt build up. This should not be done where silicon jointing exists. The mix is usually 1 part Hydrochloride Acid to 10 parts water. This is broomed on using a stiff bristled broom and washed off within 2 minutes with a further rinse 10 minutes later. Care should be taken to avoid damage to glass or other fittings from acid as well as proper ventilation and taking necessary safety considerations for use of Hydrochloric acid.

Sandstone Paving can be cleaned using chlorine. The same dosage and cleaning method is used as with the Hydrochloric acid above but more chlorine can be  added if the surface is extremely dirty. Make sure all necessary safety precautions are made whilst using chlorine. Other organic anti-fungal cleaners can also be used on sandstone.

Marble is quite often used as paving in high trafficable areas because of  it's beauty. This is not a good idea as Marble is relatively soft and can be scratched by common silica soils carried by the wind and by people's footwear. The way to protect this marble can be quite expensive but a good way to do so is to use a sacrificial coating. This can be in the form of an acrylic film or  membrane or for a lower trafficable are natural wax can be used. This  sacrificial coating will prevent any grit from even touching the marble finish  and leaving with it's original sheen and beauty. The problem with this is that  the coating may have to be re-applied every few years. If the marble floor has been damaged it may have to be re-polished or re-honed.

Marble is also not recommended for external use as it has a rapid rate of  oxidation, when exposed to wind and rain and forms a milky film of calcium carbonate on it's surface.

WALL CLADDING
Internal vertical cladding, irrespective of finish, should only need dusting to remove build-up.

External cladding should only require dusting off or in the case of grime  build up on exfoliated surfaces a wash off using higher than normal water pressure.

TEST CLEANING
In all instances a test area should be cleaned away from main traffic areas  to ensure no unexpected results or side effects are encountered.

SEALING
If soiling of a floor becomes a problem that requires inordinate cleaning  then possibly the floor should be sealed. Care should be taken in this regard because sealants can alter surface texture and colour and can cause "tracking" (heavy traffic paths can become obvious). In this instance prospective sealants should be tested by application on a thoroughly cleaned floor in a high traffic area and not throughout the building (i.e. at main entrance). Full sealant should then be applied once a satisfactory result is obtained.

STAINS
Should the paving become stained then various methods can be used to remove  it.

Attached is a report on stain removal on type of stain. This should be referred to first, however if a stain does not budge consult the stone suppliers personnel for advice.

GUILDELINE TO REMOVING STAINS
Marble and natural stone are porous materials. This porosity is why it can be  stained. It is also why stains can be removed. All that's needed to remove a stain is to reverse the staining process. In other words, the stone has literally absorbed the stain and we simply re-absorb it into a different material. The different material is what we call a poultice. A poultice can be made with powered whiting and hydrogen peroxide or a chemical reducing agent - depending on the nature of the stain. Whiting is sold in most paint stores. The  poultice should be made and applied as described for removal of each particular stain.

POULTICING
Some of the more common poulticing materials and powders are:

POULTICING MATERIALS
> Cotton Balls
> Paper Towels
> Gauze Pads

POULTICING POWDERS
> Clays (Attapulgite, Kaolin, Fullers, Earth)
> Talc
> Chalk
> Sepiolite (Hydrous Magnesium Silicate)
> Diatomaceous Earth
> Methyl Cellulose

Clays and diatomaceous earth are usually the best. Do not use whiting or iron  type clays such as fullers Earth with acidic chemicals. They will react with the material, canceling the effect of the poultice.

Many stains are so deeply imbedded that the poultice alone will not be completely effective. Some type of chemical solution will need to be added to  the poultice to dilute and/or react with the stain. The process is rather simple. When the poultice and chemical is absorbed into the stone, the chemical  reacts with the stain and is re-absorbed into the powder/material.

STAIN REMOVING CHEMICALS
How do you choose the proper chemical for a given stain?

First you need to identify the stain. This is the most important step in stain removal. If you know what caused the stain - you can easily look in a stain removal chart for the proper chemical to apply. If the stain is unknown,  then you need to play detective. Try to determine what caused the stain. If the stain is near a plant container, it might be the plant was over watered and the soil has leaked iron onto the stone. The color of the stain may help to identify the cause. Brownish color stains may be iron (rust) stains. The shape or pattern of the stain may be helpful. Small droplet size spots leading from the coffeepot  to someone's desk are sure giveaway. Do some investigating and use your powers of observation. This will almost always lead to the identification of the cause of the stain.

If, after thorough investigation, you still have no idea what the stain is,  then you will need to perform a patch test. A patch test simply means applying several chemical poultices to determine which will remove the stain.

Most stains can be classified into one of the following categories

> OIL BASED STAINS - Grease, tar, cooking oil and food stains
> ORGANIC STAINS - Coffee, tea fruit, tobacco, cosmetics
> METAL STAINS - Iron (rust) copper, bronze etc.
> BIOLOGICAL STAINS - Algae, mildew, etc
> INK STAINS - Magic marker, pen, ink etc.

There are, of course, other materials that will cause staining - but these five categories are the most common.

APPLYING THE POULTICE
Once the stain is identified, the following steps can be followed.

> Wet the stained area with distilled water. Pre-wetting fills the pores of  the stone with water - isolating the stain and accelerating the removal by the  chemical.
> Prepare the poultice. If powder is to be used, pre-mix the powder and the  chemical of choice into a thick paste of the consistency of peanut butter. In  other words, wet it enough so that it does not run.
> If paper poultice is to be used - soak the paper in the chemical. Lift the paper out of the chemical until it stops dripping.
> Apply the poultice to the stain - being careful not to spill any on the  non-stained areas. Apply approximately one-quarter-inch thick overlapping the stain area by about one inch.
> Cover the poultice with plastic (food wrap works great). Tape the plastic  down to seal the edges
> Allow the poultice to dry thoroughly. This is a very important step. The drying of the poultice is what pulls the stain from the stone into the poultice material. If the poultice is not allowed to dry, the stain may not be removed.  Drying usually takes from 24 to 48 hours.
> Remove the poultice from the stain. Rinse with distilled water and buff dry  with a soft cloth. If the stain is not removed, apply the poultice again. It may take up to five applications for difficult stains.
> Some chemicals may etch the marble surface. If this occurs, then apply polishing powder and buff with a piece of burlap to restore the shine.
> If the problem is serious in nature or too large in size, please consult your  stone supplier.

SUMMARY STEPS TO REMOVE STAINS
> Identify the stain if possible.
> Prevent re-occurence, locate the source of staining, and if possible,  prevent it from occurring again.
> Lightly scrub the stained area with a mild cleaner.
> Patch test if necessary.
> Apply poultice to the stain as per instructions.
 
TROUBLESHOOTING
All solutions are given starting with the gentlest method first. All the chemical solutions mentioned can be purchased at most hardware stores or from a marble supply distributor.

PROBLEM SOLUTION

Iron Stains (rust)
Poultice with one of the following

> Sodium citrate and glycerin
> Ammonium Oxalate
> Oxalic Acid
> Orthophosphoric Acid and Sodium Salt of EDTA in water
> Dilute Hydrofluoric Acid
> Cannot be removed, is part of the stone.

Ink
Poultice with one of the following:

> Light coloured marbles only use Bleach or Hydrogen peroxide
> Dark marbles use Lacquer Thinner or Acetone
> Methyl Chloride

Oil Based Stains
(grease, cooking oil, tar, food stains)

Clean with:

> Scouring Powder with bleach
> Household Detergent
> Ammonia
> Mineral Spirits
> Methyl Chloride

Organic Stains
(paper, tea, coffee, fruit, tobacco etc.)

> Pour Hydrogen Peroxide 35% directly on stain and add a few drops of ammonia. Leave until bubbling stops.
> Repeat above but add poultice
> Acetone or Toluene or Xylene

Efflorescence
Poultice with:

> Distilled Water

Copper Stains
Poultice with:

> Ammonium or Chloride or Ammonimum  Hydroxide

Biological Stains
(algae, moss, fungi, mildew)

Clean with

> Dilute ammonia or Bleach
> Hydrogen Peroxide or Sodium  Hypochlorite

Wax (acrylic yellow coatings)
Strip with:

> Alkaline Stripper
> Urethane Coatings
> Methyl Chloride or Grinding

Crystallisation Coatings
> Strip off with Oxalic Acid Base Stripper
> Grind Off

Paint
> Alkaline Paint Remover
> Methyl Chloride
> Grout and Thin Set Residue
> Scrub with a neutral cleaner and red pad
> Re- hone
> Scratches
> Re-polish
> Re-hone
> Streaking
> Buff with felt pad-dry
> Steel wool-dry or re-polish

Water spots and rings
> Buff with Dry steel wool
> Re-polish or re-hone