The Uses of Screeds For The Purpose Of Laying Final Flooring

Most concrete flooring as we speak are lined with a screed of some kind or one other. The exception can be a warehouse or a manufacturing facility the place the concrete could also be left uncovered since there isn’t any want for aesthetics or one thing akin to underfloor heating.

Historically, a sand and cement screed has been laid with the item of offering as close to a stage floor as attainable for the ultimate flooring to be laid on prime of it. Plain concrete doesn’t present a sufficiently stage floor on its’ personal, and different floorings akin to precast concrete beams and blocks can have a definite camber which causes hassle when laying the ultimate flooring. As we speak, one other sort of screed is quickly coming to the forefront and that’s liquid screed.

Liquid screed can truly be a liquid cement screed however is extra generally anhydrite screed which comprises gypsum. There are a number of benefits to a liquid screed, not the least of which is the velocity of laying. Whereas a sand and cement screed needs to be trowelled as flat as attainable, which suggests a labourer engaged on his arms and knees, a liquid screed is delivered to website prepared combined and is then distributed over the cement substrate by a pump. This is named a self-levelling screed, though it is going to require some levelling with a laser screed leveller. One of these screed is normally stage to SR2 (Floor Regularity 2) though in follow will usually be stage to SR1 which is pretty much as good because it will get.

Following the British Requirements Code of Follow, the floor regularity is calculated by laying a 2-metre straight edge on the floor and measuring deviations from the factors that are involved with the ground floor utilizing a slip gauge or related gadget. For many ultimate flooring surfaces, SR1 should have deviations no larger than 3mm, SR2 5mm, and SR3 10mm. Screeds that are going to obtain timber flooring should have deviations no larger than +/- 3mm from the imply when measured over a 2 metre distance utilizing a straight edge.

Sorts Of Screed

Screed may be laid in numerous methods. One is bonded screed the place the screed is absolutely bonded to the substrate utilizing a bonding agent or primer. It’s steadily used for thinner varieties of screed the place there’s going to be a heavy loading on the ultimate flooring floor and/or the place there is probably not sufficient room to put an unbonded screed. If no underfloor heating is being put in, the thickness of a bonded screed may be as little as about 15mm for anhydrite screed, or between 25mm and 40mm for a sand and cement screed.

You may as well have an unbonded screed the place a damp-proof membrane is laid over the substrate and the screed laid on prime of that. Right here, the flooring is just not in direct contact with the substrate so the issues that may be related to shrinkage or settlement may be averted. The damp proof membrane additionally prevents damp rising from the concrete. A cement and sand screed can be laid to about 50mm or extra, whereas anhydrite may very well be a minimal of 30mm.

What is named a floating screed is one that’s laid on prime of a layer of insulation. This creates a flooring which is thermally environment friendly and likewise has acoustic properties. It’s usually used the place underfloor heating is being put in, and within the case of a sand and cement screed will have to be 70mm thick, and a bit of extra if heavy hundreds are anticipated. With an anhydrite screed, the thickness may very well be put in at as little as 35mm thick for home use, and 40mm for industrial.

A floating anhydrite screed along side underfloor heating will be certain that the warmth is carried out evenly throughout the ground floor with none sizzling or chilly spots and it’ll additionally assist to retain the warmth for longer. Some anhydrite screeds may be put in with as little as 20mm protecting the heating pipes, that means a complete thickness of 40mm or much less. One other benefit of anhydrite screeds is that they are often pressure dried solely seven days after laying by incrementally turning on the underfloor heating.