UltraScape Perma-Bed 25KG: Permeable Bedding Mortar for Natural Stone Paving, Cobbles & Block Paving

UltraScape Perma-Bed is a premium permeable bedding mortar — a pre-blended, BS 7533-compliant solution for laying paving that provides a bound, free-draining base for natural stone paving, granite setts, cobbles, concrete paving, flags and block paving. It’s a product our customers consistently come back to tell us they’re delighted with: fast to open to traffic, reliable in the ground, and genuinely kind to the paving above it.

Rated for bed thicknesses from 10–100mm in a single pass, open to foot traffic in just 12 hours and vehicular traffic in 24 hours, available in contractor-friendly 25kg bags — Perma-Bed is a professional-strength permeable bedding mortar that’s equally at home on a domestic patio or a commercial block paving installation.

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. I work alongside a team of incredibly knowledgeable and caring individuals, and between us we’ve seen a lot of bedding mortars come and go. Perma-Bed is consistently one we recommend — its permeable matrix drains water away rather than trapping it, which makes a real difference to the long-term performance of the paving above it.

We recommend Perma-Bed for any bound paving installation where water management matters: natural stone patios, cobble and sett laying, block paving driveways, paths and flagged areas. Use it alongside UltraScape Pro-Prime to prime the supporting layer and the underside of all paving elements, and finish with PremJoint Brush-in Paving Grout for a complete permeable paving system. Note: Perma-Bed is suitable only for bound/rigid construction — not for unbound/flexible applications.

Key Specifications

• Unit size: 25kg bag (full pallets x 48 bags)
• Bed thickness: 10–100mm in one pass (greater depths by successive layers)
• Open to foot traffic: 12 hours
• Open to vehicular traffic: 24 hours
• Conforms to: BS 7533
• Water required: 1.75 litres per 25kg bag
• Workability: 50 minutes @ 20°C
• Yield: approx. 12.7 litres per 25kg bag
• Compressive strength: >35N/mm² after 28 days
• Flexural strength: 4.5N/mm² after 28 days
• Bond (adhesion strength): >2N/mm² after 28 days (with primer)
• Modulus of elasticity: 21,500N/mm²
• Water permeability: >2x10⁻⁴m/s
• Colour: Grey
• Shelf life: 8 months from date of manufacture (unopened, stored correctly)
• Storage: Cool, dry, frost-free area between 5°C and 30°C

Features & Benefits

• BS 7533 compliant — meets and exceeds the strict demands of the British Standard for bound paving
• Fully permeable — allows water to drain through the cured matrix, reducing water-related pavement failures
• Open to foot traffic in 12 hours, vehicular traffic in 24 hours
• 10–100mm bed thickness in a single pass
• Shrinkage compensated
• Freeze/thaw resistant
• Reduces the likelihood of reflective staining from the underside of paving elements
• Pre-blended — just add water, no on-site batching errors
• Small, contractor-friendly 25kg units
• NBS Source registered for ease of specification

Suitable For

• Natural stone paving
• Granite setts & cobbles
• Concrete paving & flags
• Block paving
• Bound/rigid paving construction (not suitable for unbound/flexible applications)

Need the Technical Datasheet?

Download the UltraScape Perma-Bed technical datasheet (PDF). For further information, call our team on 0330 122 1025 or email orders@thepavingexperts.co.uk.

Frequently Asked Questions

I’m Cleo, owner of The Paving Experts, with over 25 years in the construction industry working with businesses including Tarmac and Instarmac. I work alongside a small team of incredibly knowledgeable and caring individuals who share the same passion for getting it right. The FAQ answers below come from the questions we’re asked every single day.

What is UltraScape Perma-Bed?

UltraScape Perma-Bed is a pre-blended permeable bedding mortar designed for paving installations. It provides a bound base for natural stone paving, cobbles, concrete paving, flags and block paving, while allowing water to pass through the cured mortar. It is specifically formulated to meet and exceed the requirements of BS 7533.

What is UltraScape Perma-Bed used for?

Perma-Bed is used as a permeable bedding mortar beneath paving. It is suitable for natural stone paving, cobbles, concrete paving, flags and block paving, providing a bound and permeable base for paving installations.

Is UltraScape Perma-Bed a permeable bedding mortar?

Yes. Perma-Bed is specifically designed as a permeable bedding mortar. Once cured, the material allows water to pass through its matrix, helping water that enters the pavement through cracks or damaged areas to drain away rather than becoming trapped within the pavement construction.

Does UltraScape Perma-Bed comply with BS 7533?

Yes. Perma-Bed is specifically formulated to meet and exceed the strict requirements of BS 7533 — the British Standard for pavements constructed with clay, natural stone or concrete pavers.

What is BS 7533?

BS 7533 is the British Standard covering pavements constructed with clay, natural stone or concrete pavers. The UltraScape range is a BS 7533-compliant mortar paving system incorporating specialist bedding, priming and jointing materials.

What paving can be laid on UltraScape Perma-Bed?

Perma-Bed is designed for use beneath natural stone paving, cobbles, concrete paving, flags and block paving.

Can UltraScape Perma-Bed be used for natural stone paving?

Yes. Natural stone paving is a primary application for UltraScape Perma-Bed. The permeable bedding mortar provides a bound base while allowing water to pass through the cured material.

Can UltraScape Perma-Bed be used for block paving?

Yes. Block paving is suitable for use with UltraScape Perma-Bed.

Can UltraScape Perma-Bed be used for concrete paving slabs?

Yes. Concrete paving and flags are both suitable applications for Perma-Bed.

How thick can UltraScape Perma-Bed be applied?

Perma-Bed can be applied at a thickness of 10–100mm in a single pass. Greater depths can be achieved using successive layers.

How do you mix UltraScape Perma-Bed?

Perma-Bed is supplied pre-blended in 25kg bags. Add 1.75 litres of clean water to a suitable mixing vessel, then slowly add one 25kg bag. Mix mechanically for between 3 and 5 minutes. Do not add extra water or part-mix bags.

Is UltraScape Perma-Bed ready mixed?

Perma-Bed is supplied as a pre-blended dry mortar — the components are already proportioned and the product simply requires the addition of water on site. This reduces the risk of on-site mixing errors and helps maintain consistent results.

How much water do you add to UltraScape Perma-Bed?

Add 1.75 litres of clean water per 25kg bag of UltraScape Perma-Bed. Do not add extra water — this will weaken the finished mortar.

How long does UltraScape Perma-Bed take to set?

Perma-Bed can accept foot traffic after 12 hours and vehicular traffic after 24 hours.

When can you walk on paving laid on UltraScape Perma-Bed?

Paving laid on UltraScape Perma-Bed can accept pedestrian traffic after 12 hours, subject to the installation being carried out correctly and the relevant conditions being met.

When can you drive on paving laid on UltraScape Perma-Bed?

Paving installed using UltraScape Perma-Bed can accept vehicular traffic after 24 hours.

Is UltraScape Perma-Bed frost resistant?

Yes. Perma-Bed is frost resistant once cured. However, this material should not be used in temperatures below 5°C unless specific conditions are met: the ground must not be frozen, the temperature must be 2°C and rising, and the product must be protected from frost.

Does UltraScape Perma-Bed help prevent paving from staining?

Yes. The free passage of water through the cured Perma-Bed matrix means correctly laid paving should not suffer from reflective staining emanating from the underside of the paving elements.

Can UltraScape Perma-Bed reduce water-related paving failures?

Yes. Perma-Bed is specifically designed to allow water migrating into the pavement to drain away. Water remaining within a pavement can ultimately contribute to pavement failure through hydraulic action caused by repeated trafficking. Perma-Bed’s permeable matrix is designed to reduce these water penetration-related failures.

Why use a permeable bedding mortar rather than a standard one?

A standard bedding mortar is not permeable — water that enters the pavement through joints, cracks or damaged areas has nowhere to go and can become trapped. Over time, this water can freeze and expand, contribute to hydraulic failure from repeated trafficking, or cause staining to migrate upward through the paving. A permeable bedding mortar like Perma-Bed allows that water to drain away, protecting the pavement above it.

Do I need to prime the base before using UltraScape Perma-Bed?

Priming the supporting layer with UltraScape Pro-Prime is strongly recommended to increase overall product performance and bond strength. It is also a requirement of BS 7533 that the underside of all paving elements is primed. The bonding characteristics of Perma-Bed are only fully achieved when used in conjunction with Pro-Prime.

What primer should I use with UltraScape Perma-Bed?

Use UltraScape Pro-Prime slurry primer to prime both the supporting layer and the underside of paving elements before laying with Perma-Bed.

What jointing compound should I use with UltraScape Perma-Bed?

For a complete permeable paving system, use UltraScape PremJoint Brush-in Paving Grout to joint paving laid on Perma-Bed. PremJoint is also permeable, maintaining free drainage through the full pavement construction.

Can UltraScape Perma-Bed be used for a driveway?

Yes — Perma-Bed is suitable for driveways laid on a bound/rigid base. It is open to vehicular traffic after just 24 hours and is specifically formulated to withstand the hydraulic stresses caused by repeated vehicle trafficking.

Can UltraScape Perma-Bed be used for a patio?

Yes. Perma-Bed is an excellent choice for patio installations, particularly where natural stone, porcelain or other premium paving is being laid on a bound base. Its permeable matrix helps protect against staining and water-related failure.

Is Perma-Bed suitable for unbound or flexible construction?

No. Perma-Bed is suitable only for bound/rigid construction. It should not be used in unbound or flexible paving applications.

How does UltraScape Perma-Bed compare to a standard semi-dry mortar?

Unlike a standard semi-dry mortar, Perma-Bed is specifically formulated to allow water to pass through the cured mortar matrix. This permeability helps manage water within the pavement construction, reducing the risk of staining, efflorescence, freeze-thaw damage and hydraulic failure. It also meets BS 7533, which a standard semi-dry mortar does not.

Not sure if Perma-Bed is right for your project? Give us a call on 0330 122 1025 or drop us a message via our contact page and one of our team will help you work it out. We’re a small, family-run business and we genuinely love talking paving.

• Brand: Instarmac
• Product Type: Permeable Bedding Mortar
• SKU: TPE-PERBEDBAG61C
• Weight: 25.0 kg / 55.12 lb