*All new Roundtower NHL bag designs will be introduced gradually once old stocks of bags have been used*
Natural Hydraulic Limes (NHL) are made from limestone containing impurities which enable a hydraulic set. They are supplied as dry powders, when mixed with sand and the addition of water they set through a chemical reaction known as hydration. This chemical set allows for NHL mortars to be used in damp and more exposed locations and produce an earlier resistance to frost than lime putty.
Natural Hydraulic Lime (NHL)is supplied in three European classifications, NHL 2 (feebly hydraulic), NHL 3.5 (moderately hydraulic) and NHL 5 (eminently hydraulic). These grades are based on compressive strength.
NHL has a number of qualities:
- Lime reabsorbs a proportion of carbon dioxide (CO2) during curing and setting, thus offsetting part of CO2 created from production.
- It allows buildings to 'breathe', and does not trap moisture inside the walls.
- Lime mortars are very workable.
- Lime allows masonry to be recycled at the end of its life and does not damage brick and stone.
Roundtower NHL 3.5 is a great all-round hydraulic lime suitable for most locations and conditions. NHL (Natural Hydraulic Lime) is made from limestone which contains naturally occurring impurities. These impurities aid the setting time and hardness of the lime. Roundtower Lime contains no artificial additives included in the mix.
Roundtower NHL 3.5 is the middle strength of the 3 classifications for NHL. It is the most popular NHL.
Roundtower NHL 3.5 is ideal for the below:
- Pointing stonework, brickwork, and blocks.
- Mortars for construction.
Roundtower NHL's will set in the presence of water which makes it ideal for use on exterior applications.
Each bag contains 25kg. Each pallet contains 56 X 25kg bags.
Working temperatures should not be below 5 degrees. Make sure that high suction materials are thoroughly dampened before application. Avoid rapid drying due to high temperatures or strong winds using appropriate curing methods. Protect fresh mortar from frost, rain, direct sun and strong wind for a minimum of 48 hours depending on the time of year.
Always remember that the mortar should never be harder than the masonry.