Most concrete floors today are engrossed inside a screed of some type or other. The exception is a warehouse or possibly a factory where the concrete may be left uncovered since there is no requirement of appearance or much like underfloor heating.
Typically, a sand and cement screed remains laid while using object of offering as near a sum surface as you can for your final flooring to get laid on top from this. Plain concrete does not provide a sufficiently level surface on its’ own, as well as other floorings for instance precast concrete beams and blocks could have a distinct camber which then causes trouble when lounging the best flooring. Today, a different type of screed is rapidly going to the forefront and that is liquid screed.
Liquid screed can definitely be described as a liquid cement screed but is a lot more generally anhydrite screed that contains gypsum. There are lots of advantages of a liquid screed, and never minimal to be the rate of lounging. Whereas a sand and cement screed must be trowelled as flat as you can, meaning a labourer concentrating on his hands and knees, a liquid screed is distributed to site ready mixed which is then distributed inside the cement substrate having a pump. This really is whats known as a self-levelling screed, although it should take some levelling getting a laser screed leveller. This sort of screed is usually level to SR2 (Surface Regularity 2) although used will most likely be level to SR1 that is like it’ll get.
Carrying out a British Standards Code of Practice, the very best regularity is calculated by lounging a few-metre straight edge initially glance and calculating deviations within the points which are in contact with the floor surface employing a slip gauge or similar device. For a lot of final floors, SR1 must have deviations a maximum of 3mm, SR2 5mm, and SR3 10mm. Screeds which will probably receive timber flooring must have deviations a maximum of /- 3mm within the mean when measured greater than a 2 metre distance employing a straight edge.
Types Of Screed
Screed might be laid diversely. The very first is glued screeds where the screed is fully glued for the substrate employing a connecting agent or primer. It’s generally employed for thinner types of screeds where there’s apt to be huge loading round the final floor surface and/or high may not be enough room to place an unbonded screed. If no underfloor heating continues to be installed, the thickness from the glued screed is frequently as little as about 15mm for anhydrite screed, or between 25mm and 40mm for just about any sand and cement screed.
You may even provide an unbonded screeds where a moist-proof membrane is laid inside the substrate as well as the screed laid on top of this. Here, the flooring is not in direct reference to the substrate and so the problems which may be associated with shrinkage or settlement might be avoided. The moist proof membrane also prevents moist rising within the concrete. A cement and sand screeds might be laid close to 50mm or maybe more, while anhydrite may well be a minimal 30mm.
What’s known a floating screed is a that’s laid on top of the layer of insulation. This produces a floor that’s thermally efficient and it has acoustic characteristics. It’s commonly used where underfloor heating continues to be installed, plus the problem from the sand and cement screed must be 70mm thick, and a little more if heavy loads are anticipated. By getting an anhydrite screeds, the thickness may be installed at under 35mm thick for domestic use, and 40mm for commercial.