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| Q1.
How do I finish the interior and exterior?
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| A1. |
It is not essential to apply internal or external finishes. However, for decoration in habitable areas, DCS can be clad with plasterboard, wall paper or paint/acrylic render. The exterior wall faces can be clad with various materials including paint/acrylic render. Additional wall facings can also be used such as painted f.c. sheets, aluminium, stone or brick cladding and f.c. siding.
Where decorative finishes are not required, for example in basement walls, fire stair walls, lift shafts, warehouse and factory walls, the factory finished faces can be left exposed.
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| Q2.
Is DCS available in different colours?
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| A2. |
No. Currently DCS is only available in off white. DCS can be painted for other colour requirements.
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| Q3.
Can DCS be exposed to direct sunlight?
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| A3. |
Yes. DCS polymer does not readily degrade when exposed to sunlight (ultraviolet radiation) due to natural inhibitors used in the materials. DCS offers long term UV resistance, similar to vinyl windows.
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| Q4.
How do you protect Dincel-Building Wall against direct sunlight?
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| A4. |
The protection is only for aesthetics reasons against discolouration (yellowing) needs to be considered with Dincel-Wall if yellowing is an aesthetic concern. Dincel-Wall only offered off-white colour which is already a positive measure against yellowing. Above ground Dincel-Building walls may be protected or for architectural appearance reasons by white or pastel shade PVA paint or acrylic render finish.
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| Q5.
Is solar radiation (i.e. UV effects) important for Dincel-Walls?
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| A5. |
No. Polymers can incur minor surface damage when subjected to long term exposure to U.V. Radiation from sunlight. This affect is called U.V. Degradation.
U.V. Degradation in PVC occurs when energy from the U.V. radiation causes excitation of the molecular bonds in plastic. The resulting reaction occurs only on the exposed surface of PVC and penetrates the material less than 0.025mm. Refer to PVC Pipe Design & Installation - American Water Works Association - 2002 page 7. (http://www.books.google.com.au/books?id=LLaRltp1decC&pg=PP1&dq=1583211713).
The common effects of direct sunlight for unprotected rigid PVC polymers are:
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Loss of gloss, progression to chalking and discolouration (yellowing). This only affects the aesthetic appearance. Dincel-Wall avoids this issue, if yellowing is a concern, by having paint/render finishes on building walls subject to direct sunlight. If no paint protection or additional solar radiation reflectants are provided, loss of gloss, discolouration, and dehydro-dechlorination occurs leading to surface crazing of only a few micron thickness in which the bulk of the material thickness is unaffected.
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Brittle type of fracture can occur. The issue of loss of impact strength and brittleness, hence fracture under stress concentration can occur after a significantly long period of time which is normally a concern for the service life of water pipes, water tanks, windows etc. These profiles or empty shells normally rely on strength of the polymer itself. However, the strength of the Dincel-Wall against stress concentrations such as change in the water pressure in the case of pipes, tanks or local impact is absorbed by the concrete infill of Dincel-Wall. Therefore, the issue of brittleness, hence loss of impact strength of PVC subject to direct sunlight, if and when it occurs, is not an issue for serviceability of Dincel-Wall.
Dincel-polymer which is a PVC based product uses titanium dioxide (Ti02) pigments where it acts as a U.V. absorber to reduce the aesthetics appearance change that may occur at the product surface due to U.V. degradation.
Ti02 efficiently transforms destructive U.V. light into heat. A white powder (chalking) forms at the face of the product which is the Ti02 particles exposed to the surface. The higher the Ti02 content, the longer the aesthetics surface protection is achieved. This white powder coating of Ti02 particles can be wiped or washed from the surface and it is a very small quantity and harmless to human health and the environment for the following reasons;
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Ti02 is used as white food colouring and often used to whiten skimmed milk.
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It is used in ice creams, toothpastes, medicines, cosmetics and skin care products.
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It is used in almost every commonly available sunscreen especially for infants and sensitive skins to block U.V. light.
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There is no evidence of health hazards observed in relation to Ti02, even with people subject to high Ti02 concentrations during the production and packing processes (Refer to Wikipedia).
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DCS polymer consists of non-toxic, heavy metal free stabilisers, plasticiser free inert materials including Ti02 as approved by Work Safe Australia standards and is better than other food and potable water grade PVC products.
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| Q6.
Can decorative finishes be applied to DCS in a variety of colours and textures?
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| A6. |
Yes. An acrylic based render in a variety of colours and textures, or latex or acrylic based paints, which are compatible with DCS, are readily available from major suppliers.
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| Q7.
What are the recommended finishes for DCS?
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| A7. |
DCS does not need to have additional finishes where not required, e.g. basement walls, fire tunnels, lift and stair shafts.
The internal and external walls can have the desired texture and colour applied paint/acrylic render finishes. The most common internal finishes consist of plasterboard sheet and paint.
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| Q8.
What is external render finish of DCS?
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| A8. |
Some of the most reputable applied coating companies of Australia have developed paint/acrylic render finishes suitable for DCS surface. These companies offer appropriate warranties to the satisfaction of the industry that the applied paint/acrylic render finishes will not peel off from the face of DCS walls. The paint/acrylic render, similar to waterproofing membranes, has significant flexibility against render cracking. Download – Paint/Render Wall Finishes
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| Q9.
How is external render finish applied?
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| A9. |
For the best results the following steps are implemented:
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The surface is cleaned from dirt, grease, or concrete spillage.
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A coat of surface etching primer is applied to prepare the base for better bonding of levelling filler.
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The etched surface receives a trowelled-on coat of filler component which consists of acrylic compound, flexible enough to absorb movements of the base surface. The purpose of the filler is to fill the joints between profiles and level the surface appearance.
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| Q10.
What is the maximum service temperature of Dincel-Wall polymer?
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| A10. |
The service temperature is the temperature when the material starts to degrade. The effective service temperature of a plastic can vary significantly with the rate of loading. Apparently, small load application rates at high temperatures can have the same effect as large load application rates at lower temperatures.
The Ashby chart (University of Cambridge, U.K.) shows that for PVC the maximum service temperature is about 65°C for 50 Mpa strength. Rigid PVC offers heat deflection temperature, where softening starts to occur, at 70°C temperature or vicat softening temperature at 75°C.
Dincel-polymer which is a significantly modified version of common rigid PVC shows, under fire tests by CSIRO Australia, excellent heat release properties which are better than common rigid PVC and even plasterboard. This clearly indicates that the Dincel-polymer service temperature will exhibit a better service temperature than 65°C at the same strength level. However, irrespective of this fact the reader must remember that Dincel-Wall consists of concrete infill. The strength of Dincel-form is only required at the time of concrete pouring to hold the wet concrete pressure. Dincel-Wall, being a formwork, only requires serviceability performance at the time of concrete pouring. It is not an allowed practice of the construction industry to pour concrete at an ambient temperature of 65°C in the first place. It is therefore not a concern for Dincel-Wall if the ambient temperature reaches 70°C after concrete infilling.
The concrete industry/engineers need to be aware that the concrete’s hydration temperature needs to be considered when using high strength concrete in excess of 65 Mpa (28 days) concrete. The concrete’s hydration temperature is based on many factors including ambient temperature at the time of concrete pouring, plastic concrete’s temperature, water/cement ratio, cement/aggregates size and type and many other factors. Contact your concrete supplier to confirm appropriate mix design for strength exceeding 28 days concrete compressive strength of 65 Mpa.
When 65 Mpa concrete is prepared and poured under Australian Standards, it is a rare possibility for the concrete's hydration temperature to exceed 40°C or even 50°C if the thickness of the wall is limited to 200mm as in the case of Dincel-Wall.
DCS recommends to limit the concrete's hydration temperature to 55°C to avoid any softening related formwork deformation at the time of high strength concreting exceeding 65 Mpa.
If the question is, can Dincel-Wall be used for daily ambient temperatures reaching up to 70°C, then the answer in the case of Dincel-Wall would be a definite yes as the concrete infill has already set and hardened.
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| Q11.
Will shrinkage or temperature movement of concrete cause cracking of the rendered DCS surfaces?
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| A11. |
Conventional concrete walls crack due to the brittle nature of concrete while the concrete is still plastic.
The conventional wall panels must have joints to control the cracking since the steel reinforcement cannot have any contributing effect before concrete dries and bonds to the steel reinforcement.
Unlike conventional concrete, DCS provides a permanent, non-brittle, high tensile capacity permanent formwork which provides the perfect curing environment hence the concrete achieves additional crack resistance capacity. In addition to this, DCS also provides internal crack inducers at 125mm centres within the forms which force the concrete to have approximately 0.01mm width cracks at each crack inducer. Thus DCS distributes the contraction movements along the length of the wall and hence minimises the surface movement for the paint/acrylic render application. The paint/acrylic render used with DCS already possesses more than enough elasticity to handle the maximum movement (70 x 10-6 x 40°C x 125mm = 0.35mm) that could occur at each DCS profile. However, the possibility of having 40°C temperature variation will be an extreme rarity in Australian conditions. The flexibility of paint/acrylic render together with DCS results in absolute waterproof and crack free surfaces. There are many current examples of DCS walls already built with 60m to 80m long straight walls without any articulation or movement joints. These walls prove that the concrete contraction movement is perfectly controlled by DCS. (Download – Waterproof Walls).
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| Q12.
Will extreme temperature differences cause bulging of concrete filled DCS surfaces?
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| A12. |
All materials expand and contract. DCS performs as well if not better than conventional construction products under extreme temperatures. The system is designed to withstand extreme temperatures and fluctuations.
The permanent polymer encasing of DCS offers perfect curing conditions for concrete, reduces plastic shrinkage cracking and increases tensile and compressive capacity of normal concrete. The in-built crack initiators create controlled micro cracking (0.01mm – refer engineering manual) therefore the concrete infill does not provide restraint to the polymer encasement. The differential between coefficients of linear thermal expansion for polymer and concrete equates to a total relative movement between polymer and concrete in the longitudinal direction in between the unrestrained polymer faces in between the crack inducers which is 66mm. The theoretical expansion of the polymer face which occurs at 40°C temperature variation will then be (70 – 12) x 10-6 x 40°C x 66mm = 0.15mm. The resultant lateral bulging will not be perceptible to the naked eye.
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| Q13.
Does external render peel-off from the DCS surface?
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| A13. |
DCS controls and minimises the contraction and expansion movements of the wall surface as explained in the answers to the questions 11 and 12 above. Any differential between the DCS polymer surface and applied render finish is significantly reduced in comparison to conventional walls. The etching primer prepares the DCS surface for chemical bonding. The acrylic render base coat, being flexible enough, also absorbs any possible movement differential at the matching surfaces. In fact this combination becomes much more reliable than the conventional cement render applied to masonry, concrete or fibre-cement surfaces.
A number of reputable companies specialising in render application provide an appropriate warranty that surface peeling does not occur. Download – Paint/Render Wall Finishes
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| Q14.
How are internal plasterboard finishes attached?
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| A14. |
DCS consists of in-built channels/conduits at each surface for easy screw fixing of plasterboard which do not compromise the acoustic performance of the wall, unlike common direct glue fixing of plasterboard finishes to hard surfaces.
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| Q15.
How are exterior finishes attached?
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| A15. |
An acrylic render base coat can be applied to the surface of DCS to receive any type, colour or texture of paint or render.
Light weight wall cladding such as timber, aluminium, metal claddings or f.c. siding may be glued and mechanically screwed to in-built channels/conduits.
Stone or brick can be attached to DCS concrete walls with ties which are mechanically fixed before or after the concrete filling of the forms.
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| Q16.
What happens when the DCS panels are damaged? Can they be fixed?
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| A16. |
Small repairs can be made with repair putty as used in the car and boat industries.
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| Q17.
How can a damaged DCS panel without render finish be repaired?
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| A17. |
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Fill and level the damaged part with two part resin filler which is used in the car industry, sand the dried surface.
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Apply a coat of etching primer between the joints of the damaged DCS panel.
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Apply one or two coats of paint with matching DCS colour to the repaired panel.
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