Quick Answer: How to Point or Repoint an Indian Sandstone Patio
To point or repoint an Indian sandstone patio, the old loose jointing must first be removed, the joints must be cleaned out properly, and then the gaps between the slabs should be filled with a suitable pointing mortar or jointing compound. The finished joints should be compact, neat and slightly below the top surface of the paving.
Because Indian sandstone is a natural, porous stone, the most important rule is to keep mortar, cement residue and jointing compound away from the face of the slabs. If jointing material is allowed to dry on the surface, it can leave stains, smears or haze that may be difficult to remove.
The best method depends on the joint width, joint depth, paving condition and the experience of the person doing the work. For many UK garden patios, the main choice is between traditional wet mortar pointing and modern brush-in jointing compound. Both can work well on Indian sandstone if the joints are properly prepared and the product instructions are followed.
Pointing vs Repointing: What Is the Difference?
Pointing means filling and finishing the joints between paving slabs when the patio is first laid. Repointing means removing failed, cracked, loose or washed-out old jointing and replacing it with new material later.
The two jobs are similar, but repointing involves more preparation. Before any new jointing compound can be added, the old failed material must be removed. If this is not done properly, the new jointing may sit on top of loose dust and broken mortar, then crack, wash out or fail again.
Repointing is common on older Indian sandstone patios, especially where the joints have been weakened by age, frost, weeds, poor original pointing or repeated pressure washing. If the joints are hollow, crumbling, full of weeds or missing in places, repointing is usually needed.
Repointing Is Not the Same as Re-Laying
Before starting, it is important to understand what repointing can and cannot fix. Repointing replaces the material between the paving slabs. It does not repair a failed sub-base, poor bedding or slabs that are loose and rocking.
If the slabs are firm and stable, repointing may be all that is needed. If the slabs move, rock, sink or sound hollow when tapped, the problem is likely underneath the slab. In that situation, new jointing compound alone will not solve the issue, because the movement will usually crack the new joint again.
The simple test is to walk across the patio and check each slab. If the paving is stable and only the joints have failed, repointing is suitable. If the slabs are unstable, the affected slabs may need to be lifted and re-bedded by an installer before the joints are redone.
Which Jointing Method Is Best for Indian Sandstone?
There is no single best jointing method for every Indian sandstone patio. The right choice depends on the joint width, joint depth, drainage, bedding type, expected use and the finish you want.
| Method | Best For | Advantages | Watch Out For |
|---|---|---|---|
| Traditional wet mortar pointing | Wider joints, traditional patios and stronger hand-finished joints | Cost-effective, durable and gives a classic appearance | Needs skill; cement residue can stain sandstone if left on the surface |
| Brush-in jointing compound | Garden patios, DIY work and faster re-jointing jobs | Quicker and cleaner to apply when used correctly | More expensive; wet or dry conditions must follow the product instructions exactly |
| Two-part resin or epoxy jointing mortar | Higher traffic areas, stronger joints and frequent wash-down areas | Very durable and resistant to weeds and weather | Higher cost and shorter working time; residue must be cleaned immediately |
| Kiln-dried or polymeric sand | Very narrow joints and light-use areas | Simple and low cost | Usually not the best choice for wider Indian sandstone patio joints |
For most domestic Indian sandstone patios, the realistic choice is traditional wet mortar pointing or a modern brush-in jointing compound. Mortar gives a traditional finish and can be very strong when done well. Brush-in compounds are usually easier and quicker, especially for DIY users, but they must be used exactly as the manufacturer states.
Joint Width and Depth: What You Need
Good pointing starts with the correct joint size. If the joints are too shallow, too narrow or full of loose material, the new jointing has nothing solid to grip and may fail early.
- Indian sandstone patios are commonly laid with joints around 10 mm or wider.
- Many brush-in jointing compounds need a minimum joint width of around 3 mm to 5 mm, depending on the product.
- Many resin or brush-in products need a joint depth of at least around 20 mm, and some require more.
- Traditional mortar pointing also needs a clean, deep joint so the mortar can be pressed in properly.
- The product data sheet should always be checked for the exact minimum joint width and depth.
If the existing joint is shallow because old bedding mortar has pushed up between the slabs, it may need to be carefully cut back or raked out before new pointing is applied. A thin surface layer of jointing material will not last well on a busy outdoor patio.
Tools and Materials You May Need
The exact tools depend on whether you are using wet mortar, brush-in compound or resin-based jointing, but a typical repointing job may require:
- Stiff broom or brush.
- Weeding knife or joint scraper.
- Plugging chisel or bolster for old mortar.
- Angle grinder with a suitable mortar-raking or diamond blade, if old joints are hard.
- Dust mask, eye protection, gloves and suitable clothing.
- Hosepipe and clean water.
- Pointing trowel or jointing iron.
- Bucket, mixing board or paddle mixer if using mortar.
- Suitable jointing compound or sand and cement mortar.
- Soft brush or sponge for careful final cleaning.
An angle grinder can be useful for hard, failed mortar joints, but it must be used carefully. A slip can chip or cut the edge of the sandstone slabs. If you are not experienced with this type of work, cutting out old joints is best left to a professional installer.
How to Repoint an Indian Sandstone Patio Step by Step
Step 1: Remove the Old Jointing
Start by removing all loose, cracked, crumbling or failed jointing material. This is often the slowest part of the job, but it is essential. New jointing compound should not be applied over weak old material.
For soft, degraded joints, a joint scraper, hooked tool or weeding knife may be enough to pull out the failed material. For harder mortar joints, a plugging chisel, bolster or angle grinder may be needed. Work slowly and carefully, especially near the edges of riven sandstone slabs.
The goal is not to cut the paving itself. The goal is to create a clean, stable joint with enough depth for the new material to sit properly.
Step 2: Brush, Vacuum or Blow Out Loose Dust
Once the old material has been removed, clear out dust, grit, weeds, loose mortar and broken jointing compound. Any dusty or loose residue left inside the joint can stop the new material from sitting, bonding or curing properly.
A stiff brush is often enough for simple jobs. For deeper or dustier joints, a vacuum or careful blower may help. The cleaner the joint, the better the new pointing is likely to perform.
Step 3: Rinse the Joints and Slab Edges
After the dry debris has been removed, rinse the joints with clean water to wash away fine dust from the joint walls and slab edges. This is especially important if the joints have been cut with an angle grinder, because fine stone and mortar dust can remain inside the gap.
Use clean water and avoid very aggressive pressure. The aim is to rinse out dust, not to disturb the bedding under the slabs. Once rinsed, allow the patio to drain and reach the condition required by the chosen jointing material.
Step 4: Let the Paving Reach the Correct Wet or Dry Condition
This is where many pointing jobs go wrong. Different jointing products need different surface conditions.
- For traditional wet mortar pointing, the surface of the slabs is usually best kept dry or nearly dry, so mortar does not smear and stain the sandstone face.
- For many brush-in resin jointing compounds, the paving often needs to be wet and kept wet during application, so the compound does not stick to the dry stone surface.
- For some products, damp joints are useful; for others, a dry surface is required.
Always follow the manufacturer’s wet-or-dry instructions for the exact product being used. Do not guess. Natural sandstone is porous, and the wrong surface condition can lead to staining, residue or poor joint performance.
Step 5: Fill the Joints
If using wet mortar pointing, the mix should be workable but not wet and sloppy. A common traditional approach is a sand and cement mortar mixed stiff enough to hold its shape. The mortar should be pressed firmly into the joints with a pointing trowel or jointing tool so there are no air pockets.
Do not brush a dry or semi-dry sand and cement mix over the face of Indian sandstone. This can stain the slabs and does not create a proper durable joint. The mortar should be placed into the joints, not spread across the whole stone surface.
If using brush-in jointing compound, apply it according to the product instructions. Most products are swept diagonally across the joints until the gaps are full. Work in manageable sections and keep the surface condition as required by the manufacturer.
Step 6: Strike and Finish the Joints
Once the joint is filled, it should be finished neatly. With mortar pointing, use a pointing trowel or jointing iron to compact and smooth the joint. A slightly concave finish is often preferred because it helps shed water and gives a tidy traditional appearance.
The finished joint should usually sit slightly below the top surface of the slab, not proud of the paving. Joints that sit too high can look messy and may hold dirt. Joints that are too low may collect soil and weed seeds more easily.
Some brush-in compounds can also be finished with a trowel or jointing tool, although many are simply swept, topped up and left to cure as instructed.
Step 7: Clean the Sandstone Surface Before Residue Hardens
This is one of the most important steps when working with Indian sandstone. Mortar, cement, resin or compound residue should not be allowed to dry on the face of the slabs.
With mortar pointing, carefully remove smears before they harden. With brush-in or resin compounds, follow the manufacturer’s cleaning instructions exactly. Some products require constant water during application; others may need a particular brushing or rinsing method.
Never assume residue will wash off later. Natural sandstone can absorb stains, and dried mortar haze or resin marks can be difficult to remove without specialist treatment.
Step 8: Protect the New Joints While They Cure
Newly pointed or re-jointed paving should be protected while the material cures. Keep people, pets and garden furniture off the patio for the period recommended by the product manufacturer.
Fresh mortar should be protected from heavy rain, frost, very hot sun and rapid drying. Brush-in and resin compounds also have curing rules, and these vary by product. Some jointing products may require several days before normal use and longer before pressure washing is safe.
As a cautious guide, newly jointed paving should not be pressure washed again until the jointing material has fully cured and the manufacturer confirms it is safe. Some brush-in products may require at least 14 days before any pressure washing, and even then the jet should be kept away from the joint line and used at a shallow angle.
Common Mistakes When Pointing Indian Sandstone
| Mistake | Possible Result | Better Approach |
|---|---|---|
| Leaving loose old jointing in place | New jointing fails early | Rake or cut out failed material properly |
| Using joints that are too shallow | Compound cracks or washes out | Clean the joint to the required depth |
| Brushing dry cement mix over sandstone | Staining and weak joints | Use proper wet mortar pointing or a suitable compound |
| Using an angle grinder carelessly | Chipped slab edges | Work slowly or use a professional installer |
| Applying resin compound to dry stone when it requires wet stone | Residue marks or staining | Follow the product’s wetting instructions exactly |
| Leaving mortar or compound on the slab face | Haze, smears or permanent marks | Clean residue before it hardens |
| Pressure washing too soon after re-jointing | New joints are damaged | Allow full curing time first |
Can You Point Indian Sandstone with Sand and Cement?
Yes, Indian sandstone can be pointed with a suitable sand and cement mortar, but it must be done carefully. The mortar should be placed into the joints with a trowel, compacted and finished neatly. It should not be brushed dry across the surface of the slabs.
Traditional mortar pointing can produce a strong, clean and long-lasting joint, but it takes more skill than brush-in compound. The biggest risk is staining the sandstone face with cement residue. For that reason, many DIY users prefer modern jointing compounds, while many experienced installers still prefer well-made mortar pointing for a traditional finish.
Can You Use Brush-In Jointing Compound on Indian Sandstone?
Yes, many brush-in jointing compounds are suitable for Indian sandstone patios, provided the product is compatible with natural stone and the joint size meets the manufacturer’s requirements.
Brush-in compounds are popular because they are quick to apply and easier for many homeowners than traditional mortar pointing. However, they are not all the same. Some require the patio to be soaked and kept wet during application. Others have different curing and cleaning requirements. Always read the product instructions before starting.
On sandstone, surface staining is the main concern. Keep the stone surface in the condition required by the product, remove all excess material, and do not leave compound residue to harden on the face of the slabs.
Should Indian Sandstone Be Sealed After Repointing?
Sealing after repointing is optional. It is not required for every patio, but it can be useful if the customer wants easier cleaning and improved resistance to some stains.
Before sealing, both the sandstone and the new joints must be fully cured, clean and dry. Sealing too soon can trap moisture, affect curing or create patchy colour. The waiting time depends on the jointing material, weather and sealer manufacturer’s instructions.
A breathable impregnating sealer is usually more suitable for natural sandstone than a heavy surface coating. It can reduce water absorption and make routine maintenance easier, but it will not make the patio maintenance-free. It may also slightly deepen the colour, so a small test area is always recommended.
Final Recommendation
Pointing or repointing an Indian sandstone patio is mainly about preparation. The old failed material must be removed, the joints must be clean and deep enough, and the new mortar or compound must be suitable for natural stone.
For a traditional finish, wet mortar pointing can work very well when carried out by someone with the right skill. For many domestic patios, a good brush-in jointing compound may be easier and cleaner, provided the surface is kept wet or dry exactly as the manufacturer requires.
The key rule is simple: protect the sandstone face. Do not smear cement, mortar, resin or compound across the slabs and leave it to dry. Prepare the joints properly, fill them carefully, clean the surface before residue hardens, and allow the new joints to cure before heavy use or pressure washing.
To compare suitable paving options, browse our Indian sandstone paving, Kandla Grey sandstone paving and Indian sandstone patio packs collections.
FAQs About Pointing and Repointing Indian Sandstone
What is the best way to repoint Indian sandstone?
The best way is to remove all failed old jointing, clean the joints properly, then refill them with a suitable mortar or jointing compound. The new material must be compatible with natural stone, and any residue should be cleaned off the sandstone surface before it hardens.
Can I use sand and cement to point Indian sandstone?
Yes, but it should be used as proper wet mortar pointing, placed into the joints with a trowel and finished neatly. Do not brush a dry or semi-dry sand and cement mix across Indian sandstone, as it can stain the slabs and usually does not form a strong durable joint.
What joint width is needed for Indian sandstone pointing?
Indian sandstone patios are commonly laid with joints around 10 mm or wider. Some brush-in compounds can be used in narrower joints from around 3 mm to 5 mm, but the exact minimum width and depth depend on the product. Always check the manufacturer’s data sheet.
How deep should patio joints be before repointing?
As a general guide, the joints should usually be at least around 20 mm deep for many patio jointing products, and some products require more. Shallow joints do not give the new compound enough material to hold properly and may fail early.
Do I need to use an angle grinder to remove old pointing?
Not always. Soft or crumbling old jointing can often be removed with hand tools. Hard cement mortar may need an angle grinder with a suitable blade, but this must be done carefully to avoid chipping the sandstone edges. If you are unsure, use an experienced installer.
Should sandstone be wet or dry before jointing compound is applied?
It depends on the jointing product. Traditional mortar pointing is usually done with a dry or nearly dry slab surface to reduce staining. Many brush-in resin compounds require the patio to be wet and kept wet during application. Always follow the manufacturer’s instructions.
How long before you can walk on newly pointed sandstone?
The waiting time depends on the pointing material and weather conditions. Some brush-in compounds allow light foot traffic relatively quickly, while mortar and resin systems may need longer. Always follow the manufacturer’s curing instructions before using the patio normally.
Can you pressure wash after repointing?
Only after the jointing material has fully cured and the manufacturer says it is safe. Some products may need at least 14 days before any pressure washing. Even then, use low pressure, a wide fan nozzle and avoid blasting directly into the joints.
Why does new jointing compound fail?
New jointing compound often fails because the old material was not removed properly, the joints were too shallow, the surface was dusty, the wrong product was used, or the patio slabs were moving. Proper preparation is just as important as the compound itself.
