How to float render?

29th February 2020


How to float render?


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		What is render?
		Render, also known as stucco, is a type of plaster used on external walls and is normally made up of three parts plastering sand and one part cement, together with a waterproofing agent. You can buy render in various different colours, or paint over it afterwards.

		Two or three layers of render can be used. The first layer is most often known as the scratch coat, the second as the brown coat, and the top layer as the finish coat. Floating may be carried out on the second coat and, if there is one, the third, depending on what finish is required.

		Floating the wall
		The first (scratch) coat acts as a base for the next layer and doesn’t have to be floated, so we’ll start with the second, or brown, coat.

		Step 1 – Check render is ready Having applied the second layer of render (brown coat), wait until it starts to firm up. This can take anything from an hour to half a day, depending on the weather, the type of render and its thickness. When the render is ready to work on it should have a slightly spongy feel, but not be soft enough to leave fingermarks.

		Step 2 – Straighten render Pull a long piece of wood, called a feather edge or straight edge, over the wall to roughly straighten it. Fill in any large holes and cracks using a plastering trowel.

		Many plasterers like to also run a darby over the wall at this stage. You need to hold the darby nearly flat against the wall, with its sharp edge pointing downwards, at an angle of about 45 degrees. Pull the darby slowly upwards, pressing firmly against the render as you go to flatten the surface as much as possible.

		Step 3 – Level off render Use a wooden or plastic float in a circular scrubbing motion to even out the surface, pressing the float firmly against the wall to flatten the render. This will fill in any troughs and level off the high spots.

		Step 4 – Float top coat After floating the brown coat, wait about a week to ten days for the surface to cure and fill in any cracks that appear before applying the top coat. When it has begun to firm up, take a hard rubber float and press it against the wall in a circular motion to compact the render and make it as flat as possible.

		Step 5 – Improve the finish Use a slightly dampened sponge float to perfect the finish. The sponge gently moves the material around, so any little cracks and holes left will be filled in and the surface will look much smoother.

		Step 6 – Add texture If texture is required, you can use a nail float to scratch the wall. This is easiest to do on the same day as applying the render, before it has completely set. Pressing hard on the float, work your way up and down the wall using a circular scrubbing motion.