Permeable paving FAQs
Common questions about permeable paving

Wondering whether permeable paving is the best choice for your paving project? Our experts answer the common questions, covering the benefits of permeable paving and the recommended products for permeable jointing compounds and bedding mortars. Find out more in these frequently asked questions . 

About permeable paving

The benefits of permeable paving are: 

  • No puddling on the top of paving slabs
  • Reduced risk of flooding through rainwater run-off to drains or rivers
  • Rainwater soaks into the ground below to top-up the water table
  • Reduced risk of jointing cracks when temperatures drop below freezing

Note: For paving to be fully permeable, you must use a permeable bedding mortar and a permeable jointing compound together.

Permeable paving is when a paving system is designed to allow rainwater to infiltrate into the ground below rather than flowing into the sewage system. Using permeable paving can reduce puddling on paving slabs and ultimately the risk of flooding. 

Techniques for permeable paving include (but are not limited to): 

  • Permeable concrete
  • Porous asphalt
  • Interlocking pavers
  • Resin-bound permeable paving

For a paving system to be fully permeable, the bedding layer and jointing compound used must also be permeable. For example, you can achieve a fully permeable paving system by using Ultrascape’s Perma-bed bedding mortar and Premjoint jointing compound.

Many contractors and DIYers use permeable jointing compounds to reduce the amount of rainwater running off into nearby drains, or causing puddling on the paving slabs. 

Permeable jointing helps to reduce the pressure on the sewerage network by allowing rainwater to soak into the ground, and therefore reducing the risk of flooding. 

You must use a permeable bedding mortar with a permeable jointing compound. Otherwise rainwater will stay inside the joints. If the temperature drops below freezing, the water will expand causing the joints to crack. 

There are four types of paving slabs that are permeable (which allow water to penetrate them): 

  • Concrete block permeable paving (CBPP)
  • Clay pavers
  • No-fines concrete (a lightweight concrete)
  • Some natural stones such as Indian sandstone 

These solid paving slabs will allow water to infiltrate through them. 

However, for the paving area to be fully permeable, you will also need to use a permeable bedding mortar and jointing compound. Perma-bed and Premjoint are both a popular choice with contractors and DIYers. 

There are a few types of paving slabs that are impermeable. More commonly known as non-porous, these types of paving slabs will absorb little or no moisture: 

  • Porcelain paving slabs 
  • Natural stone such as granite and slate flags 
  • Ceramic tiles 
  • Vitrified paving flags 

Non-porous paving slabs are exceptionally resistant to stains and are easy to maintain as moss and algae will not grow on them.

About brush-in jointing compounds

Both EASYJoint and Premjoint are recommended permeable jointing compounds. 

EASYJoint is very simple to use and a preferred option for many domestic patios and driveways. 

Premjoint is a high-spec jointing compound used mainly by landscapers and other contractors. It is still, however, a popular choice for domestic projects. Premjoint is easiest to apply as a brush-in grout while wet, but can also be applied dry using a pointing trowel and jointing iron.

Use a brush-in jointing compound for your patio if you: 

  • Prefer permeable paving (also use a permeable bedding mortar)
  • Are applying grout to small areas, such as patios or walkways
  • Are paving seamless areas from indoors to outdoors

Premjoint is a high-spec, brush-in jointing compound that is permeable and easy to apply and ideal for non-traffic areas. 

Flowable slurry grout is the alternative to a brush-in jointing compound. As a cement-based product, slurry grouts – such as Flowpoint – are impermeable, more durable and ideal for professional domestic landscaping and larger, commercial projects. 

See our Flowpoint FAQs for expert advice on flowable paving grouts.

Once your patio flags are in place and secure, remove any debris from the joints and hose down the area. Empty the vacuum-packed bags onto the joints, spray with water and sweep the sand-based mixture into the joints using a long-handled brush. Aim to fill the patio jointing to just below the paving slabs. Leave to dry and cure for 24–48 hours. 

Paving jointing compounds, such as Premjoint, can also be applied as a dry mixture to your patio or pavers. This is especially important if the bedding mortar is impermeable.

About Premjoint

Premjoint is a pre-blended jointing compound used for domestic paving and commercial areas with no traffic. Permeable, decorative and formulated to a high spec, Premjoint is freeze and thaw-resistant and provides seamless paving for both inside and outside living areas. Premjoint is a sand-based product and easiest to apply wet by brushing it into a patio’s joints. It can also be applied dry.

Yes. Premjoint brush-in sand grout is a permeable jointing compound for paving inside and outside living areas.

One tub of Premjoint covers an area of 8–9.5 square metres. This is based on a paving size of 450mm x 450mm x 25mm (depth) and with an 8mm joint gap. 

When ordering Premjoint, use our handy calculator to find out how many tubs of Premjoint you need based on the measurements of your paving slabs and jointing gaps.

Premjoint jointing compound is best suited for domestic areas and walkways with no traffic. However, if you do want to use Premjoint on a driveway, for example, use an impermeable bedding mortar below the paving to support the extra weight. 

When using an impermeable bedding mortar with Premjoint, you will need to apply Premjoint as a dry product. Otherwise, the water used during a wet application will remain within the paving joints.

Premjoint can be applied either wet or dry. Although a wet application is the most popular method, only apply Premjoint wet if the patio’s bedding material is also permeable.  

How to apply Premjoint wet

  1. Ensure the paving joints are free from any debris or bedding materials
  2. Hose down the fixed paving to saturate it
  3. Pour the Premjoint sand along some of the paving joints
  4. Mist the sand-based material to keep it wet
  5. Brush the material into the joints (a regular garden brush works fine) 
  6. For best results, ensure the material is slightly below the surface of the paving 
  7. Leave to dry and cure – the patio will be ready to walk on within 24–48 hours

Note: When applying Premjoint wet, you must use a permeable bedding compound so the excess water can drain away. Ultrascape’s Perma-bed is a recommended choice. 

How to apply Premjoint dry

  1. Ensure the paving joints are free from any debris
  2. Gently mist the surfaces with water, taking care to avoid the joints
  3. Pour the Premjoint sand along the paving joints
  4. Compress the sand-based material into the joints using a pointing trowel and jointing iron 
  5. Leave to cure – the patio will be ready to walk on within 24–48 hours

Deciding whether to apply Premjoint wet or dry depends on: 

  • Whether your bedding compound is also permeable
  • The temperature at the time of application
  • Whether the area has poor drainage or poor drying conditions
  • Whether the patio will need to withstand heavier loads, e.g. cars on driveways

Apply Premjoint as a wet application if the bedding compound you have used is also permeable. If the bedding compound is non-permeable, always use a dry application – otherwise the water used during a wet application will have nowhere to drain to. 

You should also apply Premjoint dry if the temperature is dropping below 3oC, or if the area has poor drainage or drying conditions.  

If your paving needs to withstand heavier loads, such as a parked car, use an impermeable bedding material which has additional strength to support this extra weight. As such, you must use a dry application of Premjoint.

About EASYJoint

EASYJoint is a self-curing brush-in jointing compound used to fix paving tiles in place on footpaths, outdoor patios, pedestrian areas and driveways. Pre-mixed and ready to use, EASYJoint is permeable, immune to the impacts of frost and does not stain when applied correctly. Any leftover compound can be covered with water in the tub provided and saved for future use. EASYJoint is used to fill joints of at least 3mm wide and 25mm deep and helps to prevent weeds.

EASYJoint is available in five different colours to complement your chosen pavers. They are all natural sands and are not coloured with dyes of any sort:

EASYJoint colourDescription
MushroomSoft beige
Buff SandLight golden beige
Stone GreyMid grey
BasaltVery dark grey – almost black
Jet BlackJet black

EASYJoint is suitable to use in areas that are free draining and do not get waterlogged. As EASYJoint is a permeable jointing compound, the bedding material must also be permeable to allow water to fully drain through. EASYJoint needs air to cure correctly, so it is essential that water can easily flow away from the site. 

If any of these conditions do not apply to your patio, call us to discuss the best option for your paving project on 0845 862 1099 (Mon-Fri, 8.30am-5.30pm).

The paving joints also need to be at least 3mm wide and 25mm deep (ideally 30mm). Very deep joints can be filled with dry sand to reach the minimum depth. If the joints are shallower than 25mm, use a jointing tool to scrape out the bedding material alongside the edges of each individual paver to increase the depth. 

We recommend using the wet application technique for EASYJoint as it provides a stronger finish. In fact, the wetter the area is during application, the better the results.

Basically, the water helps when applying EASYJoint by: 

  • Flushing EASYJoint to the bottom of each joint
  • Minimising any oil residues sitting on the pavers
  • Clearing away any excess of the jointing compound from the patio surfaces

Surfaces can dry out very quickly during warm, sunny conditions. Be mindful and ensure you are using plenty of water.

Never apply EASYJoint using the wet application technique if the temperature is at or below freezing. Either use the dry application method or wait until temperatures increase.

Regardless of whether you are using EASYJoint or another jointing compound, a sealer is always recommended if you are working with more sensitive pavers such as polished sandstone. We recommend using EASYSeal Sandstone to protect your patio and for a long-lasting finish.

EASYJoint is ideal for grouting pavers such as natural stone, porcelain, sandstone, Yorkstone, limestone and Indian stone. It can also be used with concrete flags, granite setts and even indoor stone floor areas (although not indoor wet areas). Paving joints must be a minimum of 3mm wide and 25mm deep.

The easiest and most effective way to apply EASYJoint is using the wet application technique. Temperatures will need to be above freezing to apply EASYJoint wet. You will need a soft-broom brush, a pointing tool and a hose with a spray nozzle.

Follow these 10 easy steps: 

  1. Once pavers are laid, fully soak the whole area using a hose
  2. Pour the bag of EASYJoint onto the pavers
  3. Wet the contents to form a slurry
  4. Working quickly brush EASYJoint into the joints
  5. Keep the area wet and wash the product into the joints
  6. Once complete, top-up any joints that have sagged
  7. Brush away any excess jointing compound from the pavers
  8. Leave for 1 hour to partially cure
  9. For a smooth and slightly concave finish, run a pointing tool along the joints to strike them
  10. Any excess EASYJoint can be returned to the tub, topped up with water and saved for another time

Avoid allowing EASYJoint to sit on the pavers for too long. We recommend applying the jointing compound with a friend – one to keep the area wet (the wetter the better) and another to brush it into the joints. 

Watch the video to see EASYJoint being applied using these 10 simple steps.

Choosing a permeable bedding mortar

Use a permeable bedding mortar so that water can pass through freely and reduce the risk of reflective staining or efflorescence on patio slabs. Worse still, your patio can suffer from cracks within the grout if the water freezes, which causes the jointing to expand and break.  

Ultrascape’s Perma-bed is a permeable bedding mortar which is ideal for permeable paving. Formulated to exceed the strict requirements of the British Standards BS 7533, Perma-bed is pre-blended for ease and offers a perfect base for concrete pavers, flags, block paving, stone paving and cobbles. 

When used together with Premjoint, the permeable jointing compound, Perma-bed completes Ultrascape’s Permeable Paving System to meet the industry’s evolving demands for permeable paving.

Still have a question about permeable paving?

If you still have a burning question about permeable paving and the recommended materials for permeability, contact our expert team on 0845 862 1099 (weekdays, 8.30am–5.30pm). We’re here to help you make the best choice for your paving project.

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