Cast Stone and GFRC Precast photo album'sClick on links below
Our range of products are manufactured with two techniques:Dry Cast ProductsThe "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 CastWet Cast as the name suggests produces structural products like heads and sills but is also used for San Francisco precast 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. Introduction to Cast Stone (wet cast and dry cast) ProductsCast 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. San Francisco 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 methodThe majority of San Francisco cast stone manufactures use the semi-dry method of san francisco precast 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 napa Valley precast 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: Napa Valley Cast stone can replicate a variety of cast stoneThe 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 San Francisco 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 methodsThe production of cast stone using semidry mixes differs from that of wet method in several ways. CastingSemi 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. MixesSemi 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. Semi Standard - Cast stone items are similar to details within our Technical specification sheets. But say vary in length or require slight mold adaptation or modification. 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.
Remember adequate time must be allowed for production of concrete molds. Colors and FinishesNatural stone colors are achieved either by reliance on the color Colors of crushed rock and sands and aggregates or by the addition of pigments. White cement gray cement and a combination are often used. The use of pigments can give the cast stone greater scope in the selection of suitably graded aggregates, which permit good compaction and achieve a strong, dense mix. Iron oxides based pigments are normally used in small quantities (e.g. 0.2%-1% yellow iron oxide by weight of cement for yellow sandstone's and up to 5% red iron oxide for red sandstone). High proportions of pigment powder (above say 6 - 8% by weight of cement) are used fineline precast sometimes to achieve unusual colors like blues and browns but generally these should be avoided. 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 UseDependant 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
Cast stone by
installed in California city's such as Los Angeles, Beverly Hills, Bel
Air, Ventura or Santa Barbara has to be mechanically fastened to the wood
frame of a building usually with stainless steel or galvanized
attachments, this because of earthquake codes. There are many
historical buildings in California with cast stone as part of their
facade. Cast stone in Los Angeles, Beverly hills, Bel Air, Ventura
and Santa Barbara was at it's most popular in the 1900's. In Santa
Barbara, cast stone was used extensively in the downtown district and also
in a primitive form at the Santa Barbara mission in the form of adobe, a
mixture of mud and straw or horsehair mixed with water and hand shaped
into molds. Cast stone in the City of Ventura was used mainly on
churches in the downtown area. Cast stone in Los Angeles was used in
many important buildings including the famous Los Angeles City hall.
In Santa Barbara cast stone and Santa Barbara stone were used in
conjunction in many historical buildings. Precast Innovations Santa Barbara stone also
called Santa Barbara sandstone, is found mainly in Santa Barbara county,
is removed from the ground in loose form, the Santa Barbara stone is then
cut and shaped by a stonemason into useable blocks. Cast stone in
Beverly Hills was used in the Beverly Hills City hall and is now used on
many residential buildings. We also install our new line of
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 precast innovations concrete molds.
We have many limestone and sandstone designs installed in the Los Angeles
area.
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