Natural Hydraulic Limes (NHL’s) are so called because they set in contact with water. Secondary hardening also takes place in contact with air due to carbonation. They are produced from the burning and slaking of calcareous stone containing silica, alumina and sometimes ferrite. The resulting calcium silicates, aluminates and ferrites constitute the hydraulic component.
The quality of hydraulic limes derives from the mineralogical composition of the raw material and the manufacturer’s skill and production control. The absent of sulphates in the St Astier limestone and the low traces of alkali such as potassium and sodium cannot result in products which will favour sulphate attack or alkali-silica reactions.
St Astier NHL2 is the most feebly hydraulic lime, suitable for most mortars or renders.
St Astier NHL3.5 is moderately hydraulic and is suitable for mortars and renders in moderate to high exposure locations.
St Astier NHL5 is eminently hydraulic and suitable for mortars in high exposure and marine locations.
THE HERITAGE RANGE
Matured for a minimum of 4 months and supplied in 20L tubs, lime putty is mixed with well graded sands to produce traditional lime plasters or weak mortars for repointing.
Lime mortar should be made with good quality lime and a well graded sand.
Regular building sand can be high in finer particles making it less suitable for lime mortars.
The images below show the different sands before making the mortar and then as a mortar biscuit.
Produces a pale-yellow mortar, ideal for coarse plaster, limecrete and coarse mortars.
Produces an off-white grey mortar, chosen for colour. Perfect for flint work.
Produces a pale-yellow mortar ideal for laying and repointing, as well as medium grade plaster.
Frithend Blend 2mm
Produces a yellow mortar, chosen for colour.
Extra Fine 1mm
Produces a white mortar, ideal for fine plaster and tight joint work.
THE HERITAGE RANGE
Hand Riven Lath
Supplied in 50 x 4ft bundles, wooden lath are fixed to ceilings and walls for traditional haired plaster application.
There are different types. The most suitable are riven chestnut or riven oak and these are recommended for ceilings.
Rough sawn oak lath is also supplied for walls.
All St Astier NHL’s, graded sands, hand riven lath and lime putty are available from stock or collection from The Lime Centre or next working day delivery when ordered before 1pm.
To ensure you receive the right advice and product we prefer to talk to you first before placing an order.
Call or email us today to discuss your requirements.
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