The Most common problems:
We encounter a range of problems when dealing with cement work between the Brickwork in walls and chimney breasts. The most common of these problems can often be missing, porous or cracked mortar between the brick joints.
How do we repoint the existing Brickwork in a property?
Re-pointing the original bricks is done on the joints horizontally and vertically. In old or existing walls and chimneys the cement may chip off or become defective. The mortar joints may be ineffective and warped. This kind of job can be corrected by Repointing Brickwork by replacing the existing cement. This work has to be done delicately to avoid breaking or damaging the existing brick surfaces. The dried and defective mortar from the joints is hacked out carefully. We have found that It is better to use an angle grinder for this type of work.
Before work can begin on the existing brick work, any defective bricks should also be removed. This will ensure that when all the work that has been completed, it will look clean and pleasing to the eye. The mortar mixture to be used should be in the ratio of two parts sand and one part cement, occasionally lime will also be added to the mixture. Since this work is repeated, the soft sand should always be sieved with a gauze wire to make it fine. The existing brick work should also be checked for other defects before chipping out the loose mortar. The majority of defects include horizontal cracks, vertical cracking, porous, missing or loose mortar.
Pointing Porous Mortar joints to a wall or chimney commences by removing the old mortar with an angle grinder or a hammer and chisel. This is raked out to a depth of about half an inch to three quarters of an inch. It is extremely important to ensure that any defective and loose mortar is removed completely and brushed away leaving a clean surface to work on. The wall is then adequately watered down ready for the new cement mixture to key in. This should be done continuously for approximately one hour to the entire work area. After watering down the work area and leaving it to dry for a short period of time, the re-point can then commence.
The mortar is mixed and applied to the open joints. The mixture should not be to wet nor to stiff. A small trowel is used for putting the mortar carefully into the joints. A smooth round edged metal bar is then used to key in the mortar mix firmly in to the brick work joints. The mortar should be allowed to ooze out slightly onto the brick wall. A soft bristled hand brush is used to remove the excess mortar. The process of Pointing Chimneys and walls is repeated on the entire wall or chimney surface.
On completion of the job, the wall or chimney may be watered down after a period of twenty four hours drying time.
It is essential that the mortar mixtures used for re-pointing have similar performance characteristics to the original used in your property. Such performance characteristics include permeability, compressive strength, and coefficient of thermal expansion. For instance, if a soft lime-based mix was originally used, the most appropriate mortar mixture is likely to contain lime.
We perform a mortar analysis in order to make recommendations for the replacement cement mixture that is both aesthetically and physically compatible with your property.
Sound mortar does not normally need to be removed from your property during the process, although such a practice is common. The new mortar should be mixed to match the colour and texture of the existing mortar to avoid incompatible materials and visual aberrations. The process begins with the mortar analysis where we take a sample and examine it to identify the components, ratio, and aggregate. The old mortar is chased out to a depth equal to or slightly more than the width of the mortar joint, or to the point where sound mortar is reached. Depths greater than 4 cm will be filled in over several passes, allowing the mortar mixture to cure for at least 24 hours depending on the type of cement mix and weather conditions. The joint profile would be as rectangular as possible as the new mortar should be allowed ample opportunity to bond with the bricks.