Cement render system
View Patent ↗A method for applying render to a substrate, said method including the steps of: securing a layer of confining mesh having a three-dimensional open cellular structure to the substrate; applying a base layer of cementitious material over the confining mesh; and screening the base layer to a depth at least substantially level with an outer surface of the confining mesh. Preferably, the method includes the further step of: applying a layer of reinforcing mesh over the base layer; and applying a top coat of cementitious material over the reinforcing mesh. A cementitious plaster formulation for use in the method as defined in the method according to any one of claims 1 to 25, said formulation including: 10% to around 40% cement by weight of total dry ingredients; 50% to around 85% sand by weight of total dry ingredients; 5% to around 40% fly ash by weight of total dry ingredients; an air entraining agent and a thickener respectively combined in a ratio of from 1:1 to around 120:1 and in a combined amount of between 0.01% and around 10% by weight based on the weight of the cement; and sufficient water to provide suitable fluidity.
1. A method for applying render to a substrate, said method including the sequential steps of:
securing permanently a layer of confining mesh having a three-dimensional open cellular structure to the substrate;
applying a base layer of cementitious material over the confining mesh such that the cementitious material substantially fills the open cellular structure and is substantially supported by the open cellular structure;
screeding the base layer to a depth substantially level with an outer surface of the confining mesh;
applying a layer of reinforcing mesh over the base layer; and
applying a top coat of cementitious material over the reinforcing mesh.
2. A method according to claim 1 , wherein the confining mesh is formed from a plastics material.
3. A method according to claim 2 , wherein the plastics material consists substantially of a high density polyethylene plastic.
4. A method according to claim 1 , wherein the confining mesh is initially provided in a collapsed configuration and is selectively expandable prior to use into a three-dimensional open cellular honeycomb structure, with the size of the cells being adjustably determined by the extent of expansion.
5. A method according to claim 4 , wherein the depth of the cellular structure is between 5 nm and around 100 mm.
6. A method according to claim 5 wherein the depth of the cellular structure is between 10 mm and around 60 mm.
7. A method according to claim 6 , wherein the depth of the cellular structure is between 15 mm and around 25 mm.
8. A method according to claim 1 , including the additional step of applying the cementitious material of the base layer by shot-crete spraying onto the confining mesh so as substantially to fill the cellular structure in a single application, and subsequently screeding the cementitious material to a depth approximately level with the outer surface of the confining mesh.
9. A method according to claim 1 , wherein the confining mesh is composed and configured such that, during drying, the cellular walls act as expansion joints for the cementitious material to resist shrinkage cracking.
10. A method according to claim 1 , wherein the cementitious material for the base layer is formed from a polymer modified sand and cement plaster composition.
11. A method according to claim 10 , wherein the plaster composition includes a combination of cement, sand, fly ash, at least one air entraining agent, at least one thickening agent, and sufficient water to provide suitable fluidity.
12. A method according to claim 11 , wherein the air entraining agent and the thickener are combined respectively in a weight ratio of between 1:1 and around 120:1, and in a combined amount of between 0.01% and around 10% by weight based on the weight of the cement component.
13. A method according claim 1 , wherein the reinforcing mesh is formed from glass fibre.
14. A method according to claim 1 , including the further step of embedding the reinforcing mesh in the surface of the base layer immediately after application of the base layer.
15. A method according to claim 1 , wherein the top coat is formed from a cementitious material, substantially the same in composition as the base layer.
16. A method according to claim 1 , wherein the top coat is applied by spraying.
17. A method according to claim 1 , wherein the top coat is applied to a depth of between 1 mm and around 20 mm.
18. A method according to claim 17 , wherein the top coat is applied to a depth of between 2 mm and around 10 mm.
19. A method according to claim 18 , wherein the top coat is applied to a depth of between 4 mm and around 6 mm.
20. A method according to claim 1 , including the further step of screeding the top coat substantially level following the initial application.
21. A method according to claim 20 , including the further step of sponge finishing the top coat after screeding to provide a surface texture similar to conventional stucco render.
22. A method according to claim 1 , including the further step of applying a relatively thin finishing layer over the top coat.
23. A method according to claim 22 , wherein the finishing layer includes at least one coat of a decorative paint.
24. A method according to claim 23 , wherein the finishing layer is formed from a high build acrylic membrane paint.
25. A method according to claim 1 , wherein the cementitious material includes a cementitious plaster formulation comprising:
10% to around 40% cement by weight of total dry ingredients;
50% to around 85% sand by weight of total dry ingredients;
5% to around 40% fly ash by weight of total dry ingredients;
an air entraining agent and a thickener respectively combined in a ratio of from 1:1 to around 120:1 and in a combined amount of between 0.01% and around 10% by weight based on the weight of the cement; and
sufficient water to provide suitable fluidity.
26. A method according to claim 1 , wherein the cementitious material substantially fills the open cellular structure and the cementitious material is substantially supported by the open cellular structure.
27. A method according to claim 1 , wherein the base layer is screeded to a depth substantially level with an outer surface of the confining mesh.