There’s a common misconception about lime pointing, where some people think it’s simply a case of scraping out old mortar and pushing new material in.

But in reality, a properly executed lime repointing job is a carefully sequenced process that demands the right knowledge, the right materials, and a great deal of patience. Get any stage wrong, and you risk damaging the very fabric of the building you’re trying to protect.

So to keep that from happening, here’s what the process actually looks like, from start to finish:

Stage 1: Assessment and Mortar Matching

Before a single chisel touches the wall, the existing mortar needs to be carefully assessed. This is because not all lime mortars are the same. 

For example, the mix used on a 17th-century sandstone farmhouse will be very different from that needed on a Victorian brick terrace. Which is why at K Blythin, every project begins with a close examination of the existing mortar to match colour, texture and composition, using local sands where possible.

But we know what you might be thinking: sand is sand, mortar is mortar, so what does it matter? 

Well, if the wrong material is used, applying a mortar that’s too hard for the surrounding masonry (even a lime-based one!) can cause cracking and long-term damage. Hence, it’s important to know that the mortar must always be the weaker element in the wall. Sacrificial by design, so that any movement is absorbed by the joint rather than the stone or brick.

Stage 2: Raking Out — The Most Critical Step

The depth of mortar removed during raking out should be approximately twice the width of the joint. So let’s say for a 10mm joint, around 20mm of old mortar needs to come out, and never less than 20mm regardless of joint width.

Frankly, this is painstaking work. 

Hand tools such as plasterers’ small tools, half hacksaw blades, and specially made steel hooks are preferred to avoid damage to the stone arrises and prevent widening of the joints. Power tools can be used on harder cement-based mortars, but keep in mind that they carry a real risk of damaging surrounding masonry if used carelessly. 

In the end, the goal is to achieve a clean, square-backed joint that gives the new mortar something solid to bond to. All the while without disturbing anything that doesn’t need to be touched.

Critically, work always starts from the top of the wall down, preventing debris from contaminating freshly completed joints below.

Stage 3: Pre-Wetting

Once joints are raked clean, the masonry must be thoroughly dampened before any new mortar is applied. This is a step that’s frequently skipped by inexperienced operatives. And it’s one of the most common causes of failure!

Pre-wetting prevents the surrounding bricks or stone from drawing moisture out of the fresh mortar too quickly, which is essential for proper curing to take place. In dry or warm weather, this step becomes even more important, as rapid moisture loss leads to shrinkage cracking and poor adhesion.

Stage 4: Mixing and Application

Lime mortar should be agitated thoroughly before use.

The more it’s worked, the better it performs. Plus, only a small amount of water is needed, since too much increases the risk of shrinkage and cracking.

Soon after, mortar is applied in layers for deeper joints, pressed firmly in from a hawk, using a pointing iron or trowel, always working in the same direction. 

Remember: Joints deeper than 20mm require an initial base layer first, as applying the full depth in one go risks shrinkage occurring before the mortar has had a chance to set.

Stage 5: Finishing and Curing

Timing is everything at this stage. 

Once the mortar has stiffened, it should be firmly compacted into the joints, and the surface lightly scraped back to provide a rough, open-textured finish. This is especially ideal for carbonation and maximum moisture evaporation once fully cured. If overworked, the surface can cause lime particles to migrate outward and form a crust that restricts the carbonation process underneath.

Now comes the part that truly separates lime from cement: the cure. 

As a rough guide, pure lime putty mortars harden through carbonation at a rate of approximately one month per millimetre of thickness. This means a standard 20mm joint can take the better part of two years to fully carbonate. Hence, during this time, new pointing needs regular light dampening in drying conditions, as lime will only react with carbon dioxide in the presence of moisture. Additionally, it’ll also need protection from frost, direct sunlight, and driving rain using hessian sheeting.

This is not a material that rewards rushing, but it is one that rewards doing properly.

Why It Takes a Specialist

Every stage of this process, from reading the existing mortar to protecting the finished joint through its cure, requires experience built over years of working with these materials. 

A poorly executed repointing job doesn’t just look wrong, but it can trap damp, accelerate masonry decay, and cost significantly more to put right.

And at K Blythin Brick & Stonework, lime pointing is a craft our expert team has honed across over 60 years of combined experience. Working on everything from private period homes to listed structures across the North West and North Wales. 

So if your building deserves to be done properly, it deserves to be done by people who understand every stage of what that actually means.

Get in touch with us today at +44 7877 812 669 or info@kblythinstonemasons.co.uk

Getting Expert Intervention

K Blythin Brick & Stonework Ltd is an experienced, family-run business from Chester with over 60 years of combined experience in the brick and stone-working trade. 

We handle all manner of brickwork and stonework from lime mortar pointing & brick laying to paving & drystone walls. Rest assured, we’re qualified in heritage practices, so this means we can assist with restoration and improvements to listed properties and buildings of historical importance.