NHL Renders - Some recommended mixes
St Astier Natural Hydraulic Limes (NHL)

Background
Prepare background
Re-point and dub out as necessary with compatible mortar.
Stipple Coat Cast or sprayed on only
Must be used on poor suction, dense / smooth surfaces. Leave as Cast
Cure 2-4 days
First Coat
Cast, spray or lay on.
Well-keyed background.
Control suction. Leave Keyed
Cure 4-7 days
Second Coat
Cast, spray or lay on. Control suction. Straightening coat.
Leave keyed. Cure 7-10 days. Finishing coat in 2 coats work.
Finish
Cast, spray or lay on.Control suctionFinish as required
Cure min 3-10 days
Cob / Earth Mix 1A - Sand SG3-5mm Mix 1B - Sand SG10-15mm Mix 1C - Sand SG5-10mm Mix 1C - Sand SF / FS3-5mm
Wooden Lath   Mix 2B/3B - Sand SC12-15mm (8-10 cover) Mix 2C - Sand SC8-10mm Mix 1C - Sand SF3-5mmMix 2C - Sand SM5-8mm
Metal Lath   Mix 3B - Sand SC10-15mm (8-10 cover) Mix 2B - Sand SM10-20mm Mix 1C - Sand SF3-5mmMix 2C - Sand SM5-8mm
Soft Brick / StonePorous Blocks   Mix 1B - Sand SC10-15mmMix 2B - Sand SC10-15mm Mix 1B/C - Sand SC/SM10-12mmMix 2B/C - Sand SC/SM10-12mm Mix 1C - Sand SF3-5mmMix 2C - Sand SM5-8mm
Medium Brick / Stone / Blocks Mix 2A/3B - Sand SG*3-5mm Mix 2B/3C - Sand SC10-20mmMix 2B/3B - Sand SG**10-15mm Mix 2C/3D Sand SC/SM8-12mmMix 2C/3C Sand SG**6-10mm Mix 1C - Sand SF3-5mmMix 2C - Sand SM5-8mm
Dense Brick / Stone/ Blocks/ Concrete Mix 2A/3A -Sand SG3-5mm Mix 2B/3C - Sand SC10-20mmMix 2B/3B - Sand SG**10-15mm Mix 2C/3D Sand SC/SM8-12mmMix 2C/3C Sand SG**6-10mm Mix 1C - Sand SF3-5mmMix 2C - Sand SM5-8mm
* Stipple coat optional, depending on background suction and conditions.
** For harling applications.
Lime Mix A
1:1.5
Mix B
1:2
Mix C
1:2.5
Mix D
1:3
Mix E
1:4
NHL 2 1A 1B 1C 1D 1E
NHL 3.5 2A 2B 2C 2D 2E
NHL5 3A 3B 3C 3D  
Sands Type Particle Sizes
SG Sharp gritty 5mm down to 0.075
SC Sharp coarse 3.35mm down to 0.075
SM Sharp medium 2.36mm down to 0.075
SF Sharp fine 1.18mm down to 0.075
FS Fine soft 0.8mm down to 0.075

Note: a wide variety of finishes can be achieved by adopting different binder and sand mixes to satisfy all requirements.

Coat thickness and optional mix ratios are related to exposure and background conditions and are the responsibility of the designer.

Curing and protection must follow best working practice.

See "Protecting Lime Mortar

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For further Guidance, contact your St Astier Distributor.
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