BRICK ISSUE GUIDANCE :
LIME RUN / LIME STAINING
​SYMPTONS, PREVENTION, CURE.

Lime Run or Lime Staining is a common term used for Calcium Carbonate/Hydroxide deposits that typically emanate from mortar joint, a gap in-between the mortar joint and the brick, or sometimes a gap or crack in a brick or from weep holes within the brickwork facade.

From this point it will appear to ‘run down’ the brickwork face. 

It can often be initially confused with efflorescence as it will often be thick white in appearance, or sometimes a slight greyish appearance. 

An easy way to differentiate between efflorescence and Lime Run/Staining is that lime run will not disappear when the brickwork is wet.

It will tend to occur where the brickwork has protracted large quantities of water that follow the same track repeatedly and where excess water continuously flows through a cementitious material.
The excess water pushing through the cementacious material can dissolve calcium hydroxide which is a form of free lime that is created as Portland cement hydrates.

This then forms into a solution that finds itself to the surface of the brickwork through such openings, running down onto the brickwork face and reacting with carbon dioxide in the air to form a crusty calcium deposit. 

Often the source of the lime is the Portland cement used in the mortar joint or it can also come from adjoining concrete or cast stone products such as dry or wet cast stone copings, cills, heads, and other cast stone feature work sitting alongside brickwork.

CURE.

If Lime Run/Staining has only just appeared then it may be possible to remove it using water and gentle brushing with a soft bristled brush. 

​Avoid using a stronger bristled brush so as to not damage the face of the brick and the mortar joints.

If the Lime Run/Staining is more established and has been apparent for longer then the greater the chance that it has formed into a harder crusty calcium deposit that will be more difficult to remove. 
If so then a brick acid should be used to thoroughly clean the area of brickwork.

Wet the brickwork thoroughly beforehand and apply the relevant brick acid delicately with a soft brush.

​Repeated cleaning circles maybe required.

Staining can occur to the underlying brickwork, either from the Lime Staining itself or from the strength of the brick acid required to remove it and if so then brick tinting can be used to fully restore the brickwork back to its intended finish.

PREVENTION.

Lime Run/Staining can often be caused by inadequate protection of the brickwork during construction on site which will encourage lime material to be washed from the mortar joints during the build.  

Brickwork should be covered up during construction and building in wet weather should be avoided wherever possible.

Cement and mortar should also be covered up whilst being stored or being mixed on site. 
Mortar should be carefully and thoroughly mixed and mortar joints should be fully filled so as to ensure that excessive water does not collect in any air pockets. 

Damp Proof Courses and any Damp Proof Membranes should be should be correctly installed and you should avoid any direct water run off from adjoining floor slaps, etc.