How long do you leave scratch coat before top coat?
The first coat is a scratch coat where thats laid on and then scratched to create key for the next coat. Once thats dried usually about 24-48hours you can apply the top coat, after laying on its important to use a derby or a straight edge to rule the wall flat.
Do you put Waterproofer in a scratch coat?
Bead with scratch coat using either plastic or stainless steel stop or bell beads to get the finish. … This MUST be done before scratch coat is appied ! For Top coat the mixing process is exactly the same. Except NO mortar plasticiser, Replace this with Waterproofer, Around a cup full with water .
What to use to stick render beads?
“Secure all beads with tacks. I suggest stainless steel. You can also bed the beads on with sand and cement, the same material you’re using to render.
Do you float a scratch coat?
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.
Do you let scratch coat dry?
17. Let the scratch coat dry before going on to the next step. Drying time will depend on temperature, humidity and airflow, and could take anywhere from 2 to 24 hours. You’ll know its dry when it turns a light gray color.
How wet should scratch coat be?
The surface of the scratch coat must be hard but still moist to ensure the full strength of the coat is achieved and the next layer will adhere properly. Applying a second coat later requires that you mist or spray the walls with water to keep moisture in. Fog spraying is one way to ensure proper hydration.
How thick should scratch coat be?
The scratch coat should be 3/8″ thick. Force it through the wire mesh so that it fills the ¼” gap between the mesh and wall completely. 3. Smooth the scratch coat with the trowel.
How do you mix scratch coat mortar?
Mixing the Scratch Coat:
1 part Type S Masonry Cement to 2.5 parts sand. Dry mix the sand and cement together and avoid creating clumps in the mixture. Add water slowly to the mixture a little at a time, continually mixing until you have achieved the consistency of a paste or whipped potatoes.
How thick should a render scratch coat be?
Traditional renders should be applied in 2 coats. The first coat should not exceed 15mm thickness and the second coat should be 5-7mm.
What is the best sand for rendering?
The best type of sand to use is rendering or plastering sand. Coarse sand is usually used for the base layer, and sand that has a slightly fine texture as the top layer. Therefore, you can make use of building sand for the top or base layer.