Got a call today of a letting agency I do work for. Penetrating damp through all the wall at the rear of the property had aa look out the back and the old renders blown and knackered, so told her it needs hacking off and starting again, would you lads stick proofer in just the scratch as normal or stick it in both for good measure?
Blown render
- Thread starter allyb
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I'm on a rendering job tommorow just about to start scratch coat usually just sbr it your saying add cement powder to it
Arti
Well-Known Member
i use 1:1 sand /cement & SBR
Sorry to sound thick but you mean just paint it on as u would pva on skimming a wall before scratch coat and is your sbr neat thanks for advice
Arti
Well-Known Member
aye marra just brush it on. you can water down the SBR a little bit 50/50 if you like
carlos
Private Member
Preparation
All surfaces should be sound, free from latience, oil, grease and surface water. Before the application of a bonding slurry surfaces of high suction should be thoroughly dampened. Preparation of the surface can be achieved by the use of mechanical scrabbling or grit blasting to give a clean fresh exposed surface.
Method of use as a Bonding Agent
An SBR bonding slurry is recommended to improve the adhesion of cement based mixes onto surfaces of low suction, and also as a treatment prior to applying any SBR modified mix. To produce the bonding slurry dilute SBR Bonding Additive with an equal volume of water then mix to a smooth creamy consistency with ordinary Portland Cement. The approximate mix is 1 part SBR: 1 part water: 5 parts cement (by volume) giving an approximate coverage of 30m² per 5 litres of SBR per coat. Following preparation of the substrate as detailed above the bonding slurry should be brushed vigorously into the surface giving an approximate 1mm thickness. Subsequent coatings must be applied while the bonding slurry is still wet. Should the slurry dry then a further coat must be applied.
Rendering
To produce dense impermeable renders for use in areas where water or chemical resistance is required then the following mix is recommended.
•Cement 50 kilos
•Sand 125 kilos Clean, sharp complying with BS 1199 SBR 15 litres
•Water as required
Coverage at 12mm thickness approximately 8m²
After preparing the substrate apply a bonding slurry as described above. While the slurry is still wet, apply the rendering mix to a thickness of 6mm. Scratch the render and allow too dry for a minimum of 6 hours before applying a second 6mm coat or render. Bedding Mix The mix recommended for rendering can also be used for bonding tiles, kerb stones, coping stones, mosaics, brick slips etc. Prepare and apply the bonding slurry to both surfaces, then apply the render mix to the wall/floor and bed on the tiles etc.
Patching Mix
[FONT=arial, helvetica, sans-serif]The mix recommended for rendering can also be used for patching renders or concrete. Should reinforcing steel be present then that should be prepared by removing all loose rust then prime by applying one layer of bonding slurry and leaving overnight. A second layer of bonding slurry should then be applied to the steel and the prepared area of concrete to be patched and the rendering mix applied while the bonding slurry is still wet. [/FONT]
[FONT=arial, helvetica, sans-serif]Copied from a manufacturers web site.[/FONT]
All surfaces should be sound, free from latience, oil, grease and surface water. Before the application of a bonding slurry surfaces of high suction should be thoroughly dampened. Preparation of the surface can be achieved by the use of mechanical scrabbling or grit blasting to give a clean fresh exposed surface.
Method of use as a Bonding Agent
An SBR bonding slurry is recommended to improve the adhesion of cement based mixes onto surfaces of low suction, and also as a treatment prior to applying any SBR modified mix. To produce the bonding slurry dilute SBR Bonding Additive with an equal volume of water then mix to a smooth creamy consistency with ordinary Portland Cement. The approximate mix is 1 part SBR: 1 part water: 5 parts cement (by volume) giving an approximate coverage of 30m² per 5 litres of SBR per coat. Following preparation of the substrate as detailed above the bonding slurry should be brushed vigorously into the surface giving an approximate 1mm thickness. Subsequent coatings must be applied while the bonding slurry is still wet. Should the slurry dry then a further coat must be applied.
Rendering
To produce dense impermeable renders for use in areas where water or chemical resistance is required then the following mix is recommended.
•Cement 50 kilos
•Sand 125 kilos Clean, sharp complying with BS 1199 SBR 15 litres
•Water as required
Coverage at 12mm thickness approximately 8m²
After preparing the substrate apply a bonding slurry as described above. While the slurry is still wet, apply the rendering mix to a thickness of 6mm. Scratch the render and allow too dry for a minimum of 6 hours before applying a second 6mm coat or render. Bedding Mix The mix recommended for rendering can also be used for bonding tiles, kerb stones, coping stones, mosaics, brick slips etc. Prepare and apply the bonding slurry to both surfaces, then apply the render mix to the wall/floor and bed on the tiles etc.
Patching Mix
[FONT=arial, helvetica, sans-serif]The mix recommended for rendering can also be used for patching renders or concrete. Should reinforcing steel be present then that should be prepared by removing all loose rust then prime by applying one layer of bonding slurry and leaving overnight. A second layer of bonding slurry should then be applied to the steel and the prepared area of concrete to be patched and the rendering mix applied while the bonding slurry is still wet. [/FONT]
[FONT=arial, helvetica, sans-serif]Copied from a manufacturers web site.[/FONT]
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