When creating any form of flooring, whether it is indoors or outdoors, the ultimate aim is always for it to be as flat and level as possible. This applies whether you are installing flooring in a home, in a public building, on a patio, or even in a car park being built for a new shopping centre.
The basic material for a floor is almost always some form of concrete because that has great strength as it contains large aggregates. However, for that very reason, it is not going to be as flat and level as we would want. To achieve the smoothest finish possible requires the use of a screed which can be made of a variety of different materials and which has smaller and finer aggregates in it. This is laid over the top of the concrete. In the case of a building it can then be covered with whatever the final flooring is going to be – tile, wood, vinyl, carpet, linoleum, and more. In the case of something such as a car park, the screed itself may constitute the final surface.
Traditional screeds for indoor purposes have been made of sand and cement which is either mixed on site or today can be delivered ready mixed. The screed is then flattened out by a man using a rake and then levelled off by a labourer on hands and knees working with a trowel.
As you might imagine, this is a lengthy process and is unlikely to achieve as level a surface as is possible with other methods. Of course, if you are building a car park or school playground it would take forever working with a trowel on hands and knees! This is when a tool called a power screed is useful. Using a power screed in Bristol is a far quicker way to level the surface.
Power screeds are made in different ways. One type consists of an aluminium roller about 20’ long, to one end of which is attached a hefty right-angled drill motor to which is attached a handle for the operator to work it. To the other end is attached another handle which has no motor but has a second operator who drags the roller backwards at the same pace as the motor operator. The motor is set into motion and spins the roller forwards as the operators walk slowly backwards. This has the effect of flattening and levelling out the screed to achieve a good surface. The operators reach the end of a section of screed and then walk forwards slowly to the starting point with the roller still spinning. When they have got back to the starting point, the motor is switched off and the power screed is carried back to the next section of screed to be levelled.
A second type of power screed is called a vibrating screed, and this can be operated by one man instead of two. This consists of a long bar, again around 20’ long which has a motor and a handle in the middle of it. The motor is set in motion and has the effect of vibrating the bar as the operator walks slowly backwards over the screed. Behind him is a second man who rakes the screed out as level as possible, the final levelling being finished off by the vibrating screed. Once again, the process works in sections, the operator proceeding to the next section to be levelled when the present one is finished.
Using either of the above tools is a way of covering large areas relatively quickly in order to achieve the level surface that is needed.
Yet another tool that we use at UK Screeds is a laser screed and this has a long arm which is operated hydraulically. The machine sits at the rear of an area where the screed has just been poured from a mixer lorry and the arm with the levelling mechanism is propelled forward over the area and then brought down on to the screed. It is then drawn slowly back towards the operator and has the same effect of levelling out the screed as it goes.