Art of Lime Mortar Pointing

As a bricklayer based in South Shields, I've seen firsthand the challenges that coastal properties face. Today, I want to share a recent project where we tackled the issue of moisture penetration in an old brick house near the sea.

The Problem

Many older houses in our area were built without cavity walls, making them susceptible to moisture issues. When these properties are repointed using modern sand and cement mortar, it can actually exacerbate the problem. The hard cement mortar prevents the walls from breathing, trapping moisture inside.

Our Solution: Lime Mortar

For this project, we decided to use lime mortar, specifically NHL 5.0 (Natural Hydraulic Lime). Here's why:

1. Breathability: Lime mortar allows the wall to breathe, preventing moisture from getting trapped.
2. Strength: The 5.0 rating indicates a stronger lime mix, perfect for withstanding the harsh coastal weather we experience in South Shields.
3. Durability: It's ideal for properties exposed to sea spray and strong winds.

The Process

1. Removal of Old Mortar: We used an Irwin mortar rake attached to a grinder to remove the old cement mortar. This was a dusty job, but essential for proper repointing.
2. Cleaning: We pressure washed the joints to ensure a clean surface for the new mortar to adhere to.
3. Mixing the Lime Mortar: Our mix consisted of:
   • 3 parts soft sand
   • 1 part sharp sand
   • 1 part NHL 5.0 lime
   We mixed this for at least 30 minutes to ensure proper consistency.
4. Application: Using a pointing iron, we carefully applied the lime mortar to the joints.
5. Finishing: We used a 10mm stemmer to create a neat, finished look.

Additional Protection: Storm Dry

After repointing, we applied a product called Storm Dry. This breathable sealant provides an extra layer of weather protection without compromising the wall's ability to breathe.

Why This Matters

By using lime mortar and appropriate sealants, we are not just fixing a cosmetic issue. We are addressing the root cause of damp problems in these older properties. This solution allows the buildings to manage moisture naturally, preserving them for years to come.

Remember, when working on older properties or those in coastal areas, it's crucial to consider the specific environmental challenges. Sometimes, traditional methods like lime mortar can be the most effective modern solution.

If you're facing similar issues with your property, don't hesitate to reach out. We are always happy to assess and recommend the best course of action for your specific situation.