ProJoint V400-WT: Heavy-Duty Epoxy Resin Jointing Compound

ProJoint V400-WT is a specialist two-part epoxy resin jointing compound for filling joints between natural stone and concrete paving, slabs and setts. It is suitable for patios, domestic driveways, commercial paving and access roads, including pedestrian and vehicle areas carrying loads of up to 40 tonnes.

V400-WT is an increased-strength, cement-free, self-compacting epoxy mortar for joints from 5mm wide, with a 27KG kit, 12-hour walk-on time, 24-hour vehicle access in dry ambient conditions and full strength after 28 days.

We’re a small, family-run business — I’m Cleo, the owner, with over 25 years in the construction industry working with businesses including Tarmac and Instarmac. If you’re choosing between V400-WT and a lighter-duty resin jointing compound, the main question is how much traffic and loading the finished area will need to handle.

Why use ProJoint V400-WT?

V400-WT is the heavy-duty option in the V400/TITAN comparison. It provides a strong, durable and permeable joint for natural stone and concrete paving, with water able to drain through the joint. It can be installed on paving laid over either a permeable or non-permeable bedding system, provided the full solid bed and bedding mortar are suitable for the intended traffic loading.

• Suitable for patios, driveways, commercial paving and vehicle areas up to 40 tonnes
• Two-part, cement-free epoxy resin mortar system
• Self-compacting for fast application without bending or kneeling during compaction
• Permeable joint that allows water to drain through
• Suitable for natural stone, concrete paving, slabs and setts
• Suitable for joint widths from 5mm upwards
• Weed-, pressure-washer- and frost-resistant once fully cured
• Suitable for permeable or non-permeable bedding, provided the construction is appropriate for the intended use
• Available in Neutral, Mid-Grey and Black

V400-WT or TITAN?

Both are chemically cured resin jointing compounds, but they are intended for different traffic levels. Nexus ProJoint TITAN is a useful all-rounder for patios, paths and domestic driveways up to 10 tonnes. V400-WT is designed for heavier use, including heavily trafficked driveways, commercial areas, access roads and applications up to 40 tonnes.

V400-WT is not suitable for porcelain paving. Porcelain needs a jointing compound specifically formulated for its low-porosity surface, such as ProJoint RapidFlow.

How to mix and apply ProJoint V400-WT

1. Ensure the paving is clean and the joints are cleared to at least 25mm deep for 40-tonne traffic loading and at least 5mm wide. The paving must be firmly bedded and stable on bedding material suitable for the intended traffic.
2. V400-WT can be installed on paving with either permeable or non-permeable bedding. We recommend using ProJoint Pre-Grout Sealer before jointing where appropriate to help protect against possible resin sheen.
3. Keep soil and dirt off the prepared surface during application, as contamination can become trapped in the resin as it cures.
4. Wear suitable PPE. Liberally wet the paving and allow the water to soak into the surface.
5. Add the sand to a suitably sized bucket and begin mixing with a plasterer’s whisk. Mix for around two minutes until thoroughly combined.
6. Add 3 litres of water, equivalent to two resin containers and one hardener container, then mix for a further three minutes until the mortar becomes a free-flowing slurry.
7. Make sure the paving is still wet and the surface temperature is between 3°C and 25°C. Do not allow the paving to dry during application. Take care on dark paving in direct sunlight because surface temperatures can be high.
8. Empty the mix directly onto the paving and move it across the full area with a suitable squeegee, allowing every joint to fill completely.
9. Leave the slurry for approximately 10–15 minutes to allow the foam to disappear.
10. Using a wet, medium-soft brush at approximately 45° to the joints, sweep away excess sand and leave the paving clean.
11. Clean the paving before the product cures so residue does not set on the surface. Do not add additional water at this stage.
12. V400-WT is self-compacting, so no further compaction of the joint is required. A trowel or iron can be used once the mortar has begun to cure if a traditional finish is needed.
13. Protect from prolonged or heavy rain during curing. In dry ambient conditions, allow approximately 12 hours before foot traffic and 24 hours before vehicle traffic.

Technical information

Coverage table: 27KG kit

Download the ProJoint V400-WT technical datasheet (PDF)

ProJoint V400-WT FAQs

I’m Cleo, owner of The Paving Experts. These are the questions we’re most often asked about heavy-duty resin jointing.

What is the difference between V400 and TITAN?

Both are chemically cured resin jointing compounds, but they are designed for different traffic levels. Nexus ProJoint TITAN is an all-rounder for patios, paths and domestic driveways up to 10 tonnes. V400-WT is the heavy-duty option for heavily used driveways, commercial areas, access roads and applications up to 40 tonnes.

Can V400-WT be used on porcelain paving?

No. Porcelain has a very low-porosity surface and needs a jointing compound formulated for porcelain. For porcelain paving, use a suitable product such as ProJoint RapidFlow.

Can V400-WT be used on natural stone?

Yes. V400-WT is suitable for appropriate natural stone paving, provided the paving and installation meet the product requirements. Natural stone varies in porosity and texture, so test a small area first.

Can V400-WT be used on a driveway?

Yes. It is particularly suited to driveways with regular vehicle traffic where a heavy-duty joint is needed. It is designed for loads up to 40 tonnes.

Is TITAN suitable for driveways?

Yes. Nexus ProJoint TITAN is suited to domestic driveways, patios and paths up to 10 tonnes. For heavier use or commercial applications, V400-WT may be more appropriate.

What is the resin layer left on the surface after applying V400-WT?

A resin film or residue can remain if excess resin is not removed during application. Clean away excess as you work using the recommended damp sponge or cloth method, before it cures on the surface.

Why is my paving surface tacky after applying V400-WT?

A tacky surface is usually caused by excess resin remaining on the paving during application. Remove excess material as you work and do not allow it to cure on the surface.

How long does V400-WT take to cure?

Under ideal dry ambient conditions, allow approximately 12 hours for foot traffic and 24 hours for light vehicle traffic. Full strength is reached after approximately 28 days. Temperature, moisture and site conditions affect curing.

Is V400-WT permeable?

Yes. V400-WT allows water to pass through the joints, helping rainwater drain away and reducing standing water and puddling.

Can V400-WT be pressure washed?

Yes, once fully cured. Avoid directing excessive pressure close to the joints, as this can damage the finished joint.

Why use V400-WT instead of an air-cured jointing compound?

V400-WT uses a chemical curing process, giving the finished joint high strength and durability for areas subject to regular foot traffic, vehicle traffic and heavier loads.

Can I store V400-WT once it has been mixed?

No. Once the components and water have been mixed, curing begins and the product must be used within its working time. Do not store or reuse mixed material.

What temperature should V400-WT be applied at?

Apply when the surface temperature is between 3°C and 25°C. Temperature, moisture and weather conditions affect application and curing.

Can V400-WT be applied in the rain?

Apply in suitable conditions with the paving wet for installation, but protect the work from rain or excessive moisture during application and curing. Prolonged or heavy rain can affect the finished result.

What is V400-WT normally used for?

Typical applications include heavily used domestic driveways, commercial paving, access roads, areas exposed to heavier vehicles and high-traffic paved areas. For patios, garden paths and lighter domestic areas, Nexus ProJoint TITAN may be more appropriate.

Can V400-WT be used on patios and garden paths?

Yes, although its heavy-duty specification may not be necessary for pedestrian-only areas. Nexus ProJoint TITAN is a useful all-round option for patios and paths.

Is V400-WT suitable for commercial projects?

Yes. V400-WT is designed for heavy-duty applications where paving is subject to heavier or more frequent traffic.

How important is paving preparation before using V400-WT?

Very important. The paving must be clean, firmly bedded and stable, and the joints must meet the required width and depth for the intended loading.

How do I prevent resin from being left on my paving?

Work methodically and remove excess resin during application. Keep the paving clean as you progress, particularly on textured or porous surfaces where residue can be harder to remove.

How wide and deep should the joints be?

For 40-tonne traffic loading, joints should be at least 5mm wide and 25mm deep. Always check the current product instructions for the specific application.

Which should I choose, V400-WT or TITAN?

Nexus ProJoint TITAN is suited to patios, garden paths, pedestrian areas and domestic driveways up to 10 tonnes. V400-WT is suited to heavily used driveways, commercial paving, access areas and heavier vehicle use up to 40 tonnes. Contact us if you are unsure.

I’m not sure which jointing compound I need. Can you help?

Absolutely. We’d rather you speak to us before ordering so we can check the paving, joint width, installation, bedding and expected traffic. Call 0330 122 1025 or contact our family-run team.

Need help specifying V400-WT? Contact The Paving Experts before ordering and we’ll help you choose the right jointing compound for the project.

ProJoint V400-WT technical information

Coverage table: 27KG kit

For lighter domestic applications up to 10 tonnes, compare Nexus ProJoint TITAN.

Download the V400-WT technical datasheet (PDF)