Can I use a mortar gun with your premixed/ Hydraulic Mortars?

We are often asked if our lime mortars can be used with a conventional pointing gun.

The answer is that you can with certain machines, usually the forced action/auger based machines as opposed to the plunger type. There are some considerations that need to be taken if you are going to do this:

• Always follow machine manufacturer’s instructions particularly with regard to granulometry.
• The mix must be pliable, similar to when hand applying and the wall must be prepared (wetted down) as normal (see our technical sheets). An overly wet mix may increase shrinkage and possible cracking whilst curing – so great care must be taken with consistency.
• Both Hydraulic and Non-Hydraulic (Lime Putty) mortars are suitable for machine application.
• The usual aggregate size is 3mm down so mortar should be chosen carefully - if there is a coarse aggregate being used, this can cause blockages and the final result may not be as expected. It can also be quite aggressive in terms of wear and tear-wise on the gun!
• The mortar will still need to be well beaten back into the joint using a churn brush in order to get the desired finish.

It is important to identify the correct mortar and use an appropriate methodology to apply, so if the mix e.g. requires a larger aggregate, then we would suggest applying with a hawk and trowel/pointing iron/small tool.

Aftercare is crucial however the pointing is applied but if being applied slightly wetter through a pointing gun then it is more critical that it is tended well and pressed back to counteract shrinkage and to ensure a good connection with the background 

Please see our Lime Mortar Application guide and if you have any questions please do not hesitate to contact us on 01874 611 350 or tymawr@lime.org.uk