How to use ProJoint Titan epoxy paving grout

Nexus ProJoint Titan is straightforward to apply, but it does not forgive poor preparation or bad timing. Most problems on site – tacky surfaces, resin sheen that won’t shift, uneven curing – trace back to the same handful of avoidable mistakes.

This guide covers surface preparation, pre-sealing, mixing, application and what to do when things go wrong.

ProJoint Titan is a two-part epoxy grout. Resin and sand come pre-combined in the tub. You add the enclosed hardener on site, which triggers a chemical cure.

Once the hardener goes in, the clock starts. You cannot pause the cure or store mixed product. Get your preparation done before opening the tub.

Minimum joint requirements: 5mm wide, 20mm deep. Joints below this will not give adequate fill or bonding performance.

Not suitable for porcelain. The resin leaves an uneven sheen on dense, impermeable surfaces. Use ProJoint RapidFlow Porcelain Grout for porcelain paving.

Step 1: Prepare the surface

1. Clear all loose debris, sand and old jointing compound from the joints – a stiff brush or blower works well
2. Clean the paving surface thoroughly – remove any moss, algae or surface contamination
3. Check joint width and depth meet the 5mm wide, 20mm deep minimum throughout
4. If the paving has been recently laid, confirm the bedding mortar is fully set before grouting

Do not rush this stage. Poor preparation is the most common cause of a difficult application.

Step 2: Pre-seal the paving (recommended for most natural stone)

Pre-sealing is not always essential, but it significantly reduces the risk of resin staining and makes clean-up much easier.

Pre-seal if your paving is:

• Porous natural stone – sandstone, limestone or some granites
• Textured or riven in finish
• Light in colour or polished

You may be able to skip it if your paving is:

• Smooth, dense concrete
• A less absorbent stone such as quartzite or dense basalt

If you are unsure, seal. A suitable pre-grout sealer such as ProJoint Pre-Grout Sealer creates a barrier that stops resin bonding to the slab face, allowing clean-up to happen much more quickly during application. Apply and allow to cure before you begin grouting.

Step 3: Check the temperature and conditions

Temperature is where a lot of applications go wrong, particularly in summer.

• Recommended working range: 5°C to 20°C air temperature
• Usable range: 3°C to 25°C

The key risk in warm weather is slab surface temperature – on a sunny day with 22°C air temperature, a dark paving surface can reach 40°C or above. At that temperature the grout begins curing on the slab face before you can clean it off.

For warm conditions:

• Grout early in the morning when surface temperatures are lowest
• Work in sections rather than spreading across the whole area at once
• Keep the paving continuously misted throughout

For cold conditions:

• Below 5°C the cure slows significantly – allow extra time before use
• Do not apply in frost or near-freezing temperatures
• If temperature drops after application, allow additional curing time before traffic

Step 4: Soak the paving

Before mixing anything, soak the paving surface thoroughly with water. This is not optional.

Wet paving slows surface curing, giving you more time to work and clean excess grout from the slab face. Dry or warm paving pulls moisture from the grout quickly, making it much harder to remove residue before it sets.

Keep the surface misted throughout the entire application.

Step 5: Mix the product

1. Remove the hardener bottle from the tub and open carefully.
2. Empty the full bottle into the resin and sand mix.
3. Using a plasterer’s whisk, mix for 3 minutes until the product becomes a free-flowing slurry.
4. Do not add water.

Only mix what you can apply and clean in a single working session. More product in the tub means more pressure to rush – mix in manageable batches.

Step 6: Apply the grout

1. Pour or spread the mixed grout across a manageable section of paving
2. Use a wet medium-soft brush at a 45-degree angle to the joints to work product down into them – brushing at 90 degrees drags product out rather than pushing it in
3. Keep the surface misted continuously as you work
4. Remove excess from the slab face as you go – do not leave it to clean later
5. Use a squeegee to move remaining excess across the surface and into unfilled joints
6. Follow with a damp cloth or sponge to lift any residue from the slab faces
7. Complete the clean-up on each section before moving to the next

Any grout left on the surface advances in cure while you work. Clean as you go, not all at the end.

Step 7: Protect the area

Protect the jointed area from rain until fully cured. If there is any chance of rain, cover the area before the joints have set. The cover must not touch the fresh joints – air needs to circulate over the surface during curing. Prolonged heavy rain before the product has cured can cause fluid damage to the joints.

Resin sheen

A temporary sheen on the paving surface is normal. On natural stone it typically enriches and darkens the surface colour. It fades with weathering and foot traffic – usually within two to three months, though it can take up to six months. Pre-sealing before application is the most reliable way to minimise it.

Curing times at 20°C

• Foot traffic: after approximately 12 hours
• Light vehicular traffic (cars): after approximately 24 hours
• Full strength: develops progressively over the following days and weeks

Cold or humid conditions extend these times. Joints will continue to harden beyond what is visible at the surface – soft-feeling joints in the first few days are not a cause for concern.

Pressure washing

Once fully cured, ProJoint Titan can be pressure washed. Use a fan nozzle at a 45-degree angle to the joint – not a point nozzle directed straight into the face.

Not soaking the paving before you start

Dry paving pulls moisture from the grout quickly, causing it to cure on the slab face before you can remove it. Soak the surface thoroughly before mixing anything and keep it misted throughout the entire application.

Mixing too much product at once

More product in the tub creates pressure to rush both application and clean-up. Mix in batches sized to what you can realistically apply and clean in one working session.

Working in direct sun or high temperatures

Slab surface temperature can be significantly higher than the air temperature. In warm, sunny conditions the grout can begin curing on the surface faster than you can clean it off. Work early in the day or in overcast conditions where possible.

Cleaning at the end rather than as you go

Grout left on the slab face while you move to the next section will have advanced in cure by the time you return to it. Clean each section as you finish it, not all at once at the end.

Skipping the pre-seal on porous stone

Resin can absorb into sandstone, limestone and textured surfaces during application, causing staining that is difficult to remove after curing. Pre-sealing is a straightforward step that avoids a much more difficult problem later.

Using ProJoint Titan on porcelain

Titan is not suitable for porcelain paving. The resin leaves an uneven sheen that does not resolve with weathering. Use ProJoint RapidFlow Porcelain Grout instead.

Dealing with grout haze after curing

If resin residue has cured on the surface, a damp sponge will not shift it. A dedicated grout haze and cement residue remover such as ProJoint Eliminator is the recommended solution for stubborn surface contamination after curing.

ProJoint Titan Ultra High Strength Epoxy Paving Grout is available for next day delivery on selected in-stock items. For bulk orders or pallet quantities, call the Solseal team on 01708 855 698.