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Types of formwork and their importance

About Formwork

They serve during the execution of the works, the casting of the fresh concrete and the obtained shape and dimensions of the concrete elements, as well as for their support during the time necessary to strengthen the concrete, until the necessary mechanical resistance is obtained. Although the formwork is not a component of a definitive construction, having only a temporary role, they are of great importance in realizing the concrete and monolithic reinforced concrete works. First of all, this importance results from the role of the formwork itself to give the desired shape to the fresh concrete and maintain it until it is strengthened, influencing the surface quality of the concrete elements that come into contact with the formworks. Secondly, the importance of the formworks consists of the technical and economic influence they have on the concrete and reinforced concrete constructions, in terms of cost, labor consumption, materials and duration of execution. The influence exerted by the surface of the formwork on the quality of the superficial layer of the concrete is that related to the appearance of the concrete after decoking. For the building elements to be laid, the surface of the concrete must not be flat and it is good to be even more rough to increase the adhesion of the plaster.

Concrete pour

Sometimes, for this purpose, the shuttering is intentionally executed with a striated surface. For building elements that do not render and whose surface remains apparent, it is necessary that the surface of the formwork be as smooth as possible, in order to obtain a uniform surface of the apparent concrete. In the vicinity of the shuttering panels, the removal of air bubbles from the concrete mass is influenced by the nature of the shuttering surface. A smooth surface with a smooth, smooth, smooth surface, favors the elimination of these bubbles. In all cases it is also necessary that the surface of the formworks does not adhere to the fresh concrete, so that neither the formwork nor the concrete will deteriorate. If this adhesion is not hampered, the chippings can be broken off from the formwork or concrete. Reduction of adhesion between the formwork surface and concrete can be achieved by lubricating the formwork surfaces prior to use with suitable products or using glass fiber reinforced polyester moldings whose adhesion to concrete is reduced.

Concrete vs Steel Staircases

Choosing between concrete and steel stair structures Richard McLane summarises the key elements of concrete vs steel stair structures.Cost When budgeting for a staircase, it is misleading to compare prices of concrete vs steel structures on paper.Besides the cost of the structure, you also need to consider finish, quality, accuracy, cladding and the balustrade itself.Design The person drawing a concrete staircase rarely thinks further than the layout. Finishes, cladding, balustrade and connections are usually not taken into account at this stage.The stair and balustrade should be fully detailed before you start building any part of it! If you want a lightweight design, perhaps to let in more light, a steel structure will give you the look you want. You also have the option of choosing open treads to increase flow of light.Concrete structures are a popular choice for basement stairs, although can look clumsy in main living spaces.With any staircase, it’s important that the design works with the space available rather than take over it.Liquid concrete is dependent upon many variables including temperature, consistency, mix and builder’s experience.Concrete structures can be difficult to cast with any accuracy. Steel is controllable through design and manufacturing methods to precision measurements.On the edge Think also about the edges of the staircase. Steel stringers can be clad in timber, painted or finished with specialist metal. Most concrete staircases are plastered or painted. They may need a stringer to cover the rough concrete, which is then finished in the same way as steel stringers.Lighting Handycrew London prefer to include lighting as part of the design. We will then liaise with electricians and lighting specialist as necessary.Build Time Builders spend a lot of time shuttering and reinforcing before they can cast a concrete stair. If time is tight, a steel structure will free your builder up to work on other areas of your project.Handycrew London can usually split a staircase installation into two parts. This provides your site team with access early on in the project. We return to clad and finish when there is little danger of damage to materials.Cladding Both concrete and steel structures can be clad with a material of your choice. Cladding a staircase is an area where time is won or lost, and quality guaranteed or compromised.Drilling concrete structures for the purpose of cladding or balustrade fixing is not ideal. The process is time consuming and there is a real danger of hitting hidden reinforcing bars. Drilling into a metal bar could weaken the structural integrity of the whole staircase.Steel is safer and easier to clad with stone because responsibility remains with the staircase specialist. Handycrew London will provide CAD data to the stone supplier to CNC. Cutting all components off site increases accuracy and reduces installation time. Electronic transfer of data reduces the risk of human error. Quality and finish of the installation is much improved.A stonemason must template a concrete staircase on site. He then sends off the templates to get the treads made before returning to site to install. Fitting stone treads onto rough, inaccurate concrete structures is never straight forward. A high quality finish is usually compromised because drilling stone on site is risky. Cracking and flaking incidences are high, entailing removal, remaking and resettingHandrail & Balustrade Splitting the staircase and balustrade between suppliers may look like the cheapest option. In reality you will most likely end up paying more. There is also the hassle of coordinating several suppliers and resolving component design elements.A staircase design from Handycrew London includes staircase and balustrade. Unfortunately this is not the case with some architects or builders. On many occasions Handycrew London have come across builder staircases where the builder has overlooked the need to fix a balustrade.Despite all this, it IS possible to retrofit a balustrade to all types of staircase. The best results are always obtained by using one supplier for staircase and balustrade. This route provides a jig for the balustrade and handrail in the workshop. Installation becomes a matter of reassembling and everything goes together on site as planned.A balustrade supplier will have to template the stair before making and fitting. When he starts drilling into the concrete, he may face a similar situation to the stonemason. By this time though, he also has a layer of cladding to contend with.In summary Consulting a staircase designer is always going to give you the best results. Handycrew London consider the staircase and stair area from both form and functional aspects. We work as part of your project team to ensure the staircase becomes a seamless part of the build process.Cutting out a specialist and handing architects plans to a builder or fabricator is not recommended. This route may limit your options and compromise the outcome.For more information to help you decide concrete vs steel stairs, please contact a member of our sales team.