How to Repoint Damaged Brickwork Mortar Joints

The Step-by-Step DIY Guide

The DIY Checklist:
What You’ll Need

Over time, wind, rain, and winter frosts weather away the mortar between your home's bricks. Damaged, crumbling, or missing mortar joints allow moisture to penetrate brickwork, which can lead to damp walls and structural frost damage. Repointing is the process of raking out the failing mortar and replacing it with fresh, weather-tight mortar. Having the right collection of tools, safety gear, and fresh mixes makes this job clean, straightforward, and highly effective.

1.

SAFETY
GEAR
(PPE)

Dust Mask (P2 or FFP2): Essential to protect your lungs from breathing in fine silica dust when raking out old mortar joints.

Safety Glasses: Crucial protection against flying shards of old mortar, dust, and sand debris.

Heavy-Duty Work Gloves: Protects your hands from rough brick edges, abrasions, and chemical mortar burns.

2.

TOOLS &
EQUIPMENT

Jointing Tools (or Plugging Chisel): A specialized hand chisel or plugging chisel used to break away and clean out old, cracked mortar safely.

Gauging Trowel / Pointing Trowel: Small, narrow trowels designed to hold, slide, and pack wet mortar cleanly into narrow joint gaps.

Stiff Bristle Brush: Crucial for sweeping away loose sand particles and dust from the cleaned joints before applying new mortar.

Spray Bottle: Used to dampen the brickwork joints with clean water, preventing dry bricks from sucking moisture out of your new mortar too quickly.

Plasterer’s Mixing Tub & Shovel: Provides a clean, wide base for preparing and blending your dry mortar components with water.

3.

Materials, Fixings & Accessories

Ready-Mixed Pointing Mortar: High-performance, weather-resistant pre-blended dry sand and cement pointing mortar (typically sold in 20kg or 25kg bags).

Mortar Plasticiser (Optional): A helpful liquid additive mixed into the water to make your mortar buttery, easier to trowel, and more resistant to freeze-thaw damage.

Top Tip: Dampen the Joints First.

Dry old bricks act like dry sponges. If you pack wet mortar into a dry brick joint, the bricks will instantly suck the water out of the mix. This causes the mortar to dry out too fast, powdery, and weak, making it crack and fall out in a matter of months. Always spray the raked-out joints with water using a spray bottle shortly before packing in the new mortar.

Top Tip: Choose the Right Weather.

Mortar hates extremes. Never attempt a repointing project if rain is forecast, or if temperatures are expected to drop below 5 degrees Celsius within 48 hours. Frost will freeze the water in wet mortar, causing it to crumble, while direct summer heat will dry it out too fast. A calm, overcast Irish day is absolutely perfect for the job.

Step-by-Step DIY Installation Guide

STEP

01

Rake Out the Old Mortar

Set the Depth:

Put on your safety glasses, gloves, and dust mask. Use your plugging chisel and hammer (or jointing raker) to remove the failing mortar.

Aim for 15mm Depth:

Carefully chip away the old mortar until you reach a clean, solid depth of roughly 12mm to 15mm. Avoid hitting or chipping the horizontal edges of the bricks.

STEP

02

Brush and Clean the Gaps

Clear the Debris:

Use your stiff bristle brush to sweep vigorously inside the raked-out joints. Removing all loose sand and residual dust is critical to ensure the new mortar bonds securely to the solid brick surfaces.

Mist with Water:

Fill your spray bottle with clean tap water and mist the cleared brick joints. The surfaces should be damp but not dripping wet.

STEP

03

Mix the Mortar

Batch Prep:

Empty your pointing mortar mix into your clean plasterer's mixing tub.

Get a Smooth Mix:

Add clean water gradually, stirring with your shovel or gauging trowel. Keep mixing until it reaches a smooth, firm, and buttery consistency. It should hold its shape on your trowel without sliding off or dripping.

STEP

04

Pack the Horizontal Joints (Bed Joints)

Load Your Hawk or Trowel:

Place a good scoop of mortar onto a flat board (or a plasterer's hawk) held flush against the wall just below the horizontal joint.

Press Firmly:

Use your pointing trowel to push the mortar deep into the horizontal joints. Pack it firmly in thin layers (approx 6mm layers at a time) to prevent hollow air pockets.

STEP

05

Fill the Vertical Joints (Perpends)

Pack the Verticals:

Take small amounts of mortar on the tip of your pointing trowel and pack the vertical perpends. Work systematically from top to bottom, ensuring the joint intersections are completely filled and continuous.

STEP

06

Strike and Tool the Joints

Check for Firmness:

Let the mortar set slightly until it is thumbprint hard (firm but still moldable to firm pressure).

Shape the Joints:

Run your jointing tool (such as a barrel jointer or Y-jointer) along the horizontal and vertical joints. This compresses the mortar, drives out any remaining air pockets, and creates a neat, water-shedding surface profile.

Brush Clean:

Once the joints are finished, wait a short while and use your dry, stiff bristle brush to gently sweep away any loose mortar crumbs from the brick faces before they cure hard.

How to Repoint Damaged Brickwork Mortar Joints: Irish DIY Guide

Brickwork Mortar Joint Calculator

1. Define Brickwork Wall Sections

Wall Area Label

Length (m)

Height (m)

2. Joint Specifications & Buffers

Joint Width (mm):

Raking Depth (mm):

Trim Spillage Allowance:

Repointed Joint Profile Preview

Estimated Materials Required

Total Repointing Area: 0.00 m²

Ready-Mixed Mortar Needed: 0.00 kg

Mortar Mix Bags (25kg size): 0 Bags

Spray Bottle (Units): 0 Units

Stiff Bristle Brushes: 0 Units

Standard Mortar Yield Specs:
• Mortar Coverage Rate: At a standard joint configuration of 10mm width and 15mm depth, a typical brickwork face consumes roughly 12kg of dry pointing mortar mix per square metre.
• Pre-Blended Basket Rules: Calculations are configured for standard 25kg ready-mixed bag volumes to cover typical Irish brick configurations seamlessly.

DIY Project Shopping Checklist

Brickwork Repointing Shopping Manifest

Calculated Total Overhaul Surface: 0.00 m²

1. Dynamic Calculated Materials & Core Basket Items

GOT IT	MATERIAL DESCRIPTION	TARGET QUANTITY REQUIRED
☐	Weather-Resistant Dry Ready-Mixed Pointing Mortar (25kg Bags)	0 Bags (0.00 kg)
☐	Trigger-Operated Water Spray Bottle (1L Capacity)	0 Unit(s)
☐	Stiff-Bristled Hand Brush	0 Unit(s)

2. Required Tools & Accessories Package

GOT IT	TOOL NAME	APPLICATION PURPOSE
☐	Professional Plugging Chisel or Joint Raker	To easily rake out old, cracked, and failing mortar joints safely
☐	Gauging Trowel or Pointing Trowel	Designed to pack, hold, and smooth wet mortar inside narrow brick gaps
☐	Metal Jointing Tool or Barrel Jointer	For compressing and shaping professional, weather-tight joint profiles
☐	Plasterer's Mixing Tub, Shovel & Gauging Container	Essential for mixing clean, uniform batches of mortar smoothly

3. Mandatory Safety Gear (PPE)

GOT IT	SAFETY ITEM	PROTECTION STANDARD
☐	FFP2 / P2 High-Efficiency Airborne Particulate Dust Mask	Protects lungs from harmful silica dust raised during old mortar removal
☐	Wrap-Around Impact Protective Safety Glasses	Guards eyes from flying masonry chips and dust debris
☐	Heavy-Duty Abrasive & Chemical Resistant Work Gloves	Protects hands from brick cuts and alkaline cement chemical burns

Present this custom calculated summary list to the building merchant counter assistant to build your project basket easily.

How to Repoint Damaged Brickwork Mortar Joints

The DIY Checklist: What You’ll Need

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Step-by-Step DIY Installation Guide

STEP

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STEP

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Brickwork Mortar Joint Calculator

Estimated Materials Required

DIY Project Shopping Checklist

1. Dynamic Calculated Materials & Core Basket Items

2. Required Tools & Accessories Package

3. Mandatory Safety Gear (PPE)

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The DIY Checklist:
What You’ll Need