Repointing An Interior Stone Wall?

This tutorial focuses on repointing a stone wall, a crucial part of repairing an old masonry wall to ensure its longevity and performance. Heritage homes expert, Alan Tierney, shares his six practical steps for pointing brickwork and repairing the stone foundation.

To begin, fill a plant mister with water and spray the mortar to keep down the dust. Use a mason’s hammer and pointed trowel to chip and scratch out the old, loose mortar from the joints between the stones. Rake out the joints using a chipping hammer to a minimum depth of 2 inches. Brush down the stone walls to remove any needy cracks.

The process can be considered as 4 stages, with sample panels executed prior to repointing. Before starting with the mortar, clean out as much old mortar and debris as possible. Make more mortar, fill more gaps, brush the mortar, and repeat until the whole wall is finished.

When repointing a stone wall, rake out the joints using a chipping hammer to a minimum depth of 2 inches. Buy a bag of powdered hydrated lime (not NHL) and make it into putty, keeping it submerged in water in tubs. Research the correct sand to use and work small lumps into the joints slowly, like creating pottery.

In the first stage, rake out and remove old or inappropriate mortar to a minimum depth of 25-40 mm or until sound mortar is achieved. The depth of the joint is relative to the existing mortar.

Is there an alternative to repointing?

Tuckpointing is a specialized mortar repair process that mimics the appearance of thin joints between rubbed bricks, creating a clean and seamless result. It involves removing mortar before applying a new layer of brick-colored mortar, with a thin layer of pale putty in the center. Tuckpointing is ideal for improving the brick’s appearance but may sacrifice repair quality. If you’re more concerned about long-term repair and don’t want to sacrifice appearance, repointing may be a better choice. Repointing replaces crumbling and deteriorated mortar with fresh mortar, focusing more on functionality to strengthen the building and prevent water damage.

What are the common mistakes when repointing brickwork?

Common brick restoration errors made by inexperienced and unreliable contractors include incorrect choice of mortar, excessive reliance on caulk or grout, improper pointing finishes, incorrect curing and drying procedures, and structural and water damage. Brick restoration is a profession that requires expertise and precision, and not all restoration companies are created equal. Some may make costly mistakes that can put your masonry’s structural integrity and appeal at risk. Understanding these common pitfalls can equip you with the knowledge needed for a successful masonry restoration journey on your property.

Can repointing go wrong?

Repointing masonry walls can significantly affect their appearance and durability, as improper or incorrect materials can damage the brickwork. Masonry walls need to regulate water penetration and evaporation to prevent damage. Building control is a process that requires approval from an Approved Inspector (AI) to ensure compliance with building regulations.

The building control process involves submitting a building regulations application, which can be costly and time-consuming. It is important to note that smaller home improvements may not require building control approval. If you have been affected by the expiry of your Approved Inspector’s insurance, you should inform your neighbors about your building work. You can obtain a copy of the building regulations Approved Documents from the relevant authority.

If you are considering selling your home, building control approval may be needed for any building work carried out before you owned the house. If you don’t have the right permission for building work, you can appeal if your Full Plans application is rejected. Building control can help if building work has gone wrong and can appeal enforcement notices.

Various types of building projects, such as loft conversion, garage conversion, extension, conservatory, electrical work, internal alterations, basement, and porch, require building control approval. Approved inspectors may face problems once their insurance expires, and the project must be reverted to the local authority. The cost of canceling an initial notice and reverting work to the local council is high, and you must pay twice for the Approved Inspector and LABC team.

The government and LABC are working to help in this situation, providing further information and updates.

Can you repoint over old pointing?

Repointing over old pointing involves removing old mortar between bricks or stones and replacing it with new mortar. In some cases, the old mortar may need to be completely removed before new mortar mix can be applied. However, if the old pointing is in good condition and has not deteriorated too much, new mortar may be applied. Assessing the old pointing’s condition and determining the appropriate method for repointing is crucial for ensuring the structure’s longevity and stability.

What can go wrong with repointing?

Inappropriate repointing techniques can result in significant deterioration of stone and brick structures, promote the accumulation of excess moisture, and accelerate the rate of decay. The use of cement-based mortar for historic wall repointing is inadvisable due to its inherent strength, inflexibility, and impermeability.

What is the best mix for repointing stone walls?

The type of mortar used depends on factors such as stone type, wall condition, location, and environmental factors. Lime should be used for all stone, with a mix of 1 part lime to 2. 5 parts sand. For joints up to 10mm wide, use fine sand, while for 10mm and above, use sharp concrete sand to prevent shrinkage issues. For those unfamiliar with lime, finding a local specialist lime merchant can provide a premixed mortar that can be color-matched.

Masons Mortar Ltd is a recommended supplier in the area. If using sandstone or similar, lime is necessary, as cement will make the wall look bad and make it appear sore. A quick Google search will show the closest supplier.

What mortar to use to repair a stone wall?

The anonymous user suggests using a 6 or 8 to 1 mix with 1 part lime for stone, as it is stiffer and can be used as brickwork mortar. The mix should be made stiffer than brickwork mortar and keep joints as small as possible. The user also suggests using hydrated lime with sharp sand for grey stone, as it will harden over time and still breathe. If the stone is lighter or yellow, washed sand can be used to match the stone color. The anonymous user advises against using a cement-based mix due to its lack of breathability, which can cause the stone to erode through freeze thaw.

Lime, on the other hand, survives and weathers longer than cement, as seen on a 1500-year-old clapper bridge. If the stone is very hard and dense, a NHL 5 lime can be used, but a NHL 3. 5 is preferable mixed with a 2. 5 sand to 1 lime ratio. Different colors can be achieved by using different sand colors.

How to replace mortar between stones?

To create a well-compacted mortar, use a brick trowel to push it into the joints, ensuring it is free of air pockets. Tool it to the same height as the surrounding joints, scrape off excess mix, and dump it back into the wheelbarrow. Dip the trowel in water to prevent sticking and clean any mortar smears with a damp sponge. Allow the mortar to set slightly before the final pack-down for a polished look and prevent future cracks.

How do you repair an internal stone wall?

To repair damage to stone walls from frost heave, erosion, and deterioration, follow these steps: remove the stone, reinsert the stone, mark the area, chisel the mortar, clean stones, rebuild the wall, chip out the mortar, and mix new mortar. Natural factors like erosion and frost heave can cause damage, while mortared walls are less susceptible. If the wall isn’t repaired promptly, it poses a safety hazard.

It’s advisable to replace damaged stone with synthetic stone made from epoxy or cement-based materials, as these are less expensive and may become conspicuous over time. Ultimately, the repair process should be done to maintain the wall’s appearance and functionality.

How to repoint an internal stone wall?

To properly repoint old brick pointing, use a depth of 10mm and avoid destabilizing large joints in stonework. Cement mortar can be difficult to remove and can cause damage, so wait until necessary. Use hand tools and avoid using an angle grinder. Use appropriate lime mortar, matched to the old pointing if possible. Hot mixed mortar is best, especially in damp walls, but be cautious of health and safety.

Press the mix into joints, knock back, and tend the mortar as it goes off. Finish with an open texture, set back from the face and not covering the masonry units. Protect drying mortar from frost, direct sun, and wind.

Cement brick pointing can cause problems as it is more absorbent and softer than bricks, causing water to concentrate in the mortar rather than the masonry. Cold weather thaw action erodes the mortar, requiring periodic repointing. Cement became the predominant material for mixing mortar during the 20th century.

Can you point stone with sand and cement?

The traditional sand and cement mix is a popular choice for pointing outdoor paving due to its strength and flexibility. A mix ratio of 4 parts sand to 1 part cement is typically used. This guide focuses on pointing Indian Sandstone paving for a durable finish, ensuring its longevity and aesthetic appeal. Proper pointing seals gaps between stones, preventing water ingress and weed growth, which can undermine the stability of patios or gardens. Indian Sandstone is a versatile paving choice for any outdoor space, formed from sedimentary rock composed of quartz and other minerals.

Its unique blend of colors and patterns makes each piece distinct, with variations ranging from soft beiges to rich browns and grays. Popular choices include Rainbow Indian sandstone, Storm grey Indian sandstone, and RAJ blend Indian sandstone.