Roundtower lime NHL 3.5 is a moderately hydraulic lime, suitable for building and render mortars where a NHL 2 lime mortar is considered too weak. NHL 3.5 is stronger than NHL 2, however it is also less flexible and less breathable, factors to be considered especially with historic buildings.
NHL Mortars have a faster setting time than Hydrated (putty lime) mortars, which is useful where there are time considerations. For Historical buildings with solid walls, where the optimum levels of breathability and flexibility is necessary, we would recommend the use of a lime putty mortar.
Roundtower Limes contain no artificial additives. Available in 25kg water resistant bags.
NHL 3.5 is ideal for:
- Rendering and Plastering
- Limecrete
- Mortars for construction
- Pointing Stonework, brick and Block
NHL will set in the presence of water which makes it ideal for use on exterior applications.
For lower density masonry (e.g. limestone & sandstone) you may wish to to consider using NHL 2.
For higher density masonry, areas that are particularly exposed you may wish to consider using the NHL 5.
Always remember that the mortar should never be harder than the masonry.
Approximate coverage rates
Plastering & Rendering with a mix of 2.5 parts sand to 1 part lime at 10mm thickness covers approximately 8m².
Pointing Rubble Stone with a mix of 2.5 parts sand to 1 part lime covers approximately 10m².
Pointing Brickwork with a mix of 2.5 parts sand to 1 part lime covers approximately 16m².
|
Application Examples |
NHL type | Suggested mix ratio by volume |
| Pointing / building / plastering | NHL 2 / NHL 3.5 |
2.5 Sharp sand : |
| Laying Flag stones / Limecrete slabs | NHL 5 | 2.5 Sharp sand : 1 Hydraulic lime |
|
Paving, copings, chimneys, |
NHL 5 | 2 Sharp sand : 1 Hydraulic lime |
Further information
We have a great selection of articles about lime and it's use. Everything from hotlime to bag-rubbing. Take a look at our Lime Products guide for information and inspiration.
