Cast stone and precast concrete products

By: Ventura Cast Stone  09-12-2011
Keywords: Natural Stone, Limestone, Concrete Products

Dry Pack Cast Stone and Precast Concrete products and textures. (805) 386-8185   Fax: (805) 671-9371

Glossary of products

Description: Foam Coated Precast (glass fiber reinforced)

Description: GRG (glass fiber reinforced gypsum)

Glossary of Textures

These textures are also on our texture page.

 

 

 

 

 

 

Coral texture, made in precast concrete or GFRC product, rich natural stone texture resembling cut coral or keystone.
Coral is a limestone that has been formed for thousands of years in marine regions, we simulate the texture with silicone rubber molds taken from coral texture.
The stone is almost pure white on extraction and has natural antiquing which we simulate with concrete stains.
Natural Coral is becoming increasingly rare, and was very popular until a few years ago, but has now become too expensive for most projects.
Lightweight thin wall GFRC or full weight precast, with smooth polished surface with many small irregular fissures and swirls.
Made from crushed limestone or aggregates, fiberglass reinforcement, cement, and integrated pigment.
Hand laid into molds.
More expensive than our base price.   

 

 

 

 

A short lesson on our concrete products.

Cast Stone

Cast stone is most often used  in classical homes requiring the fine sanded texture and sharp details common to fine European or East coast estate homes.
Cast stone, used by man since the Egyptian pyramids were constructed, is hand packed into molds under tremendous pressure, just as in nature when limestone is made from the extreme pressure on sand, lime and slurry over thousands of years. This technique of compacting sand, crushed limestone and colored pigment with a small amount of water ensures a product which closely resembles limestone. Uniform in color and texture because very little water is used in it's production, cast stone is used where limestone or sandstone is desired but is cost prohibitive. The surface of cast stone shows the aggregate naturally at its surface, simulating limestone or sandstone. Pleasing, high quality texture, our favorite.
The difference between high end cast stone and normal precast concrete is easily seen, and even the novice can appreciate the high quality limestone like finish on a cast stone product. Made with old time European  techniques and reconstituting crushed limestone in our mix which gives our product a very special  texture and quality, unseen in normal precast products. Larger parts can sometimes be made in lightweight form.     
Cost's slightly more than our other products because of the Materials used and the special molds needed in it's manufacture.

GFRC  (glass fiber reinforced concrete)

GFRC is just another term for lightweight precast concrete and  is usually used in more contemporary  themed homes using the old world, travertine, or others of our many textures resembling the stone of the Mediterranean, Tuscany and even old Mexico.
We simulate aged stone by hand laying a mix of special aggregates and cement into molds with special "techniques", making the product look  time worn or aged, resembling the old stone moldings seen at many historical sites or buildings. The GFRC product is thinwall about 3/4" thick and is extremely strong and about 25% the weight of solid stone.
GFRC can also be sprayed into molds, resulting in a smooth unblemished surface.

Precast concrete

Precast concrete is usually used in more contemporary  themed homes using the old world, travertine, or others of our many textures resembling the stone of the Mediterranean, Tuscany and even old Mexico. We manufacture precast concrete products similar to the products made by other manufacturers except we have 12 different beautiful textures unseen in normal precast.
We also simulate limestone or sandstone by pouring a mix of wet concrete into molds and when cured are then sand washed, to remove the fine cured cement particles at the surface of the product, and hopefully expose the aggregates to give the product the highly desired limestone "look".
Precast concrete can also be sprayed into molds, resulting in a smooth unblemished surface.

 

Lightweight cast stone.


We at Ventura Cast Stone, Inc are pleased to introduce this lightweight GFRC cast stone or lightweight precast concrete.
Because lightweight cast stone is made from fiberglass strand mixed with real crushed limestone-cement matrix which gives it that stone look, it is suitable for architectural columns, balusters, window/door trim and fireplace mantle treatments requiring the look and feel of real stone.
Lightweight precast concrete is usually called GFRC or glass fiber reinforced concrete, and is installed in the Los Angeles, Ventura and Santa Barbara Counties. Precast concrete weights aprox 100 lbs per cubic foot, GFRC weights aprox 10 lbs per cubic foot, being hollow inside.
Precast concrete simulates older carved sandstone and does not simulate limestone as does cast stone. Precast concrete resembles finished concrete and the surface looks mainly smooth with added texture. Cast stone resembles limestone. Lightweight GFRC precast concrete is not a new product and has been used for years in architectural products.

 

Table 1: Exposures of Architectural Precast
Exposure categories Description Techniques
Nonexposed Cement paste only, as removed from the form Form finish (as cast)
Form liners
Light Matrix dominant, surface skin of cement and sand is removed Acid etch
Abrasive blast
Cast stone
Medium Coarse aggregate is exposed in equal areas to the matrix, 50/50 Surface retarder
Abrasive blast
Acid etch
Bushhammering
Deep Greater coarse aggregate exposure, very little matrix is seen Surface retarder
Abrasive blast

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 Last modified: 04/04/11    

Copyright © 2002  Ventura Cast Stone, Inc.
PO Box 552, Somis, CA 93066   (805) 386-8185 Fax: (805) 386-3002

Our range of products are manufactured with two techniques:

The "Dry Cast" method is a two part process, a face material to give you the similar finish to natural stone. Mechanically compacted to the rear of this is the backing mix to give the units strength in the terms of handling ability

Dry cast units are immediately demolded after casting and are hand finished to a very high standard.

Wet Cast

Wet Cast as the name suggests produces structural products like heads and sills but is also used for slabs, beams and other similar products, that are for high exposure or structural situations where greater loads are required on the finished unit. The Wet Cast also has the added advantage of specialist finishes with the use of special sand aggregates.

Cast Stone is known by a variety of other names including art stone, reconstructed stone, reconstituted stone, artificial stone and manufactured stone. This defines cast stone as any material manufactured with aggregate and cementicious binder and intended to resemble in appearance, and be used in a similar way to, natural stone. Cast stone is either homogenous through out or consists of a facing material and backing concrete.

The method of production is split into two categories.

Choice of manufacturing method

The majority of cast stone manufactures use the semi-dry method of production. And is the more commonly widely used method of manufacture. Early consultation with us is advisable to ascertain the correct method of production for your project.

Sizes: Components produced using the semidry method are limited in size with face dimensions of Ashlar units normally no greater than 1200x600mm. This is mainly because of the fact a semi dry mix is used, which require rapid and rigorous compaction with hand held pneumatic tampers. The semidry method of production is best suited to traditionally sized ashlars quoins, sills, copings, door and window surrounds, etc.

Structural requirements: Components requiring reinforcement which is more complex than a few straight bars or a layer of fabric reinforcement, must be produced using the wet cast method of production. This is because it is difficult to achieve thorough compaction of semidry mixes around congested reinforcement.

Appearance: Cast stone can replicate a variety of cast stone  and . The semidry method of production is used to simulate limestones and sandstones. Where a component has a particularly intricate pattern or profile including slender projections, precast concrete may have to be used in preference to the 'semidry' method. Good color matching between components can be achieved by both methods, although fineline precast textural differences become apparent at close range.

Economics: Rapid production rates with frequent reuse of molds are possible with cast stone produced using semidry mixes. Where as with the Wet Cast process a higher number of concrete molds is required to achieve the same casting program, but careful thought a planning stages of the contract can minimize the number of concrete molds. In Fact an additional 2-3 weeks extra lead-time for standard or semi standard products can sometimes be all that is needed to achieve the same casting program.

Comparison between the semidry and wet methods

The production of cast stone using semidry mixes differs from that of wet method in several ways.

Casting

Semi Dry ~ De-molding takes place immediately after compaction. This allows a rapid casting cycle with e.g. up to 80 or more basic components (sills, copings, etc.) a day from a single mold.

Wet Cast ~ Where as to manufacture the equivalent in wet cast it would not only take longer but you would require 1 mold per cast per day i.e. to produce 80 units a day you would need 80 molds.

Semi Dry ~Compaction is carried out by pneumatic tampers rather than by vibration.

Wet Cast ~ Compaction is carried out by vibration.

Mixes

Semi Dry ~ *Separate facing and backing mixes are often used for components like ashlars, sills, heads and jambs, where the backing mix is concealed from view. Separate facing and backing mixes are used primarily to economize on the facing mix. This requires a separate facing mix to be not less than 20 mm thick at any point, with semidry cement sand facing mixes and concrete backing mixes each mix is placed and compacted in immediate succession to ensure that they are effectively monolithic.

Wet Cast ~ Wet Cast units are manufactured from a through colored homogenous mix.

Semi Dry ~ Water repellent admixtures are invariably used in facing mixes to reduce permeability. Giving a water absorption of Grade B. All constituents are accurately weigh batched with the moisture content monitored regularly. Mix batches are necessarily small to prevent any premature drying of the mix. Thorough mixing and compaction are critical to ensure that the cast stone achieves the required density (typically between 1850-2100kg/m2), compressive strength and permeability.

Wet Cast ~ superplasticisers and accelerators are used to ensure good flow of the mix during vibration and compaction to achieve a smooth, compact and blow hole free finish (where ever possible finish smooth after dressing) also to give good early strength. Typical cube tests at 7-10 Days are that of the equivalent of that of a semi dry unit at 28 Days

Products are split into three categories.

Standard - Cast stone items that are manufactured in accordance with our Technical specification sheets. These items could be stock items or units, which are ready to cast at the first available production slot, with no molds to produce. Products like standard head, sills or pier caps and copings. The cost of establishing the molds is not same, thus for small production runs costs can be kept to the minimum. Also not forgetting lead times can be much shorter by not having to detail, obtain approval and then construct molds.

Purpose Made - Cast Stone items which are manufactured in accordance with the contract documents. These units are made from new purpose made concrete molds. These would probably be specialized units, which are not contained in our brochure. We have our own in house design department, who will assist you in the process of your design advising you in Careful thought must be given in the planning process for purpose made products. Please consider the following.

Design and detailing of in house production drawings- Some times it is of necessity to produce working drawings of Architects details to enable production of molds.

This process can some times take any thing from 2-10 days, dependant on how long it takes to get details approved.

Approval of production drawings.
Production of Patterns- Sometimes it is necessary to produce units from urethane or silicone rubber molds.
This may involve the pattern being produced and before molds are manufactured, approval of the pattern may be necessary from the Architect or Client.
Approval of production patterns
Manufacture of concrete molds
Production of Units
Curing of units
Packaging and Transportation to Site

Remember adequate time must be allowed for production of concrete molds.

Colors and Finishes

A variety of traditional ashlar finishes can be replicated with cast stone, including plain, boasted, tooled, rockfaced, vermiculated. The other ashlar finishes are normally produced from latex:sand or concrete mold liners.

Here is where specialist aggregates can be used to achieve some wonderful and varied finishes and colors.

Structural Use

Dependant on the situation all cast stone both Wet and Dry Cast can be used. But there are limitations in the Dry Cast process as opposed to Wet Cast: -

Cast Stone

Cantera stone columns, easy homeowner installation CDI or "Can Do It"  precast columns and we do our own concrete design ,  CDI is short for "Can Do It" columns, Sierra stone cast stone columns and balustrade, California precast products, CDI "Can Do It" precast, precast  moldings and stairs. We also supply and  install CDI "Can Do It" precast  concrete window and door trim, Sierra stone products, using our own concrete design, full weight precast and granite or limestone products,  California precast columns, precast or limestone moldings and  fireplace mantles. We manufacture our own concrete molds. We have many limestone and sandstone designs installed in the Los Angeles area.

 These products include: cast stone columns, limestone, precast concrete, precast, cast, stone, limestone, sandstone, Beverly Hills,Beverly,Hills,Beverly Hills precast,Beverly Hills cast stone, los angeles, ventura, santa barbara, los angeles precast, los angeles columns,cast stone,precast concrete,concrete columns,los angeles precast,los angeles columns,santa barbara precast,santa barbara cast stone, santa barbara columns,santa barbara stone,los angeles cast stone,santa barbara columns,ventura cast stone,ventura precast,ventura columns, ventura concrete columns, los angeles cast stone, Cantera stone columns, santa barbara precast, santa barbara cast stone, santa barbara stone, santa barbara columns, ventura cast stone, ventura precast, ventura columns, ventura stone. These products include: cast stone, limestone, precast concrete, Los Angeles concrete columns, precast, cast, stone, limestone, sandstone, los angeles, ventura, santa barbara, los angeles precast, los angeles columns,los angeles commercial precast columns los angeles cast stone, santa barbara precast, santa barbara cast stone, santa barbara stone, santa barbara columns, ventura cast stone, ventura precast, ventura columns, ventura stone, concrete molds, Malibu precast, Malibu stone, Malibu columns. We have many limestone and sandstone designs installed in the Los Angeles area.

We have installed products made by Sierra concrete design, Sierra stone and Dura art stone, Stone legends, Cantera stone columns, precast concrete,concrete columns,los angeles precast. Moonlight molds, Fineline precast, Studio cast design, Architectural products, Haddonstone, California precast, Adriatic precast, APS precast, napa stone, Studio Cast precast,

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 Last modified: 04/04/11    

Copyright © 2002  Ventura Cast Stone, Inc.
PO Box 552, Somis, CA 93066   (805) 386-8185 Fax: (805) 386-3002

Keywords: Cast Stone, Concrete Products, Crushed Limestone, Limestone, Natural Stone, precast, Precast Concrete, Precast Concrete Products, Ventura

Other products and services from Ventura Cast Stone

09-12-2011

Cast stone, precast concrete, GFRC products

Used for centuries in Europe and in the United States in the 1900s, cast stone has gained widespread acceptance in the architectural community as a suitable replacement for many masonry materials and for all types of natural cut building stones. Cast Stone is a highly refined architectural building stone, usually made up of white cement and a combination of various sizes aggregates of white marble, quartz, or other durable white stone.