Jointing and Pointing For Paving (Sand & Cement Mix)

June 23, 2023

Patio pointing is important for both looks and durability. It protects the layers under your paving, stops weeds, and makes your patio look better. Good pointing helps your patio last longer. This guide covers old and new ways to point patios. It'll help you understand how to keep your outdoor spaces in great shape, whether you're doing it yourself or hiring someone. We'll look at different methods so you can choose what's best for your patio.

1. Dry Brush Grouting

Dry brush-in pointing differs from wet grouting by requiring a completely dry environment. For optimal results, both the mortar mix and paving surface must be free of moisture. This allows the sand and cement blend to fill joints evenly.

The paving surface must be absolutely dry before application. Even minor dampness can cause unwanted adhesion and possible staining. This method works best on warm, dry summer days.

For ideal outcomes, use slightly dry building sand or Kiln Dried Jointing sand. While some experts may opt for coarser sands, be aware that this can lead to a rougher finish in dry grouting applications.

How much sand and cement mix for paving joints?

The mix is precise: a 3:1 ratio of sand to cement, with a strict no-water rule. This ensures a consistent, uniform colour in the resulting powder, signifying a thorough blend of the components. Once prepared, this mixture is evenly spread over the paving surface and gently swept into the joints using a soft brush.

When it comes to the "dry brush-in" technique, there's a notable challenge. The weight of the dry sand/cement mix is so light that it often doesn't settle well into the joints. Instead, it tends to sit fluffily, not presenting a solid appearance. However, skilled contractors have a workaround. They employ a pointing bar or a trowel blade to firmly press the mix, ensuring it compacts well into the joint. This pressing and brushing-in process is repeated until the joints are satisfactorily filled.

There's also another method that some consider more straightforward. After filling the joints, the surface is lightly misted with clean water. This not only helps the dry mix settle into the joint but also provides the slight moisture needed for the cement to start setting. However, this method has its limitations. Once the surface is damp, adding more dry mix becomes challenging. While on a scorching summer day, the surface might dry quickly, allowing for multiple rounds of this process, such ideal conditions are rare throughout the year.

Do patio sand and cement joints need to be wet?

Dry brushing-in, if not done correctly, can lead to subpar joints. Without proper wetting, the outcome is often a fragile, short-lived filler that can become a haven for weeds. Beware of contractors who neglect this, as they might leave you with a deteriorating patio after pocketing their payment.

Packaging and filling the joints adequately before introducing any water is essential for a quality joint. While this method can yield decent results, it still might not match the durability of a wet slurry joint. Combine dry brushing-in with freshly buttered joints during flag laying for the best outcome. This "butter mortar" (a typical wet mortar) provides the needed moisture for the dry mix to set. Ensure the dry mix is firmly pressed into the joint alongside the butter mortar for a long-lasting, sturdy joint.

2. Brush-In Jointing Compound

Brush-In Jointing Compound, often a blend of ready-mixed sand and cement, offers a modern twist to the age-old method of dry brush grouting. Tailored explicitly for the purpose of filling in the spaces between paving slabs, this compound is becoming a go-to choice for many homeowners and professionals alike.

Its rise in popularity can be attributed to several factors. Firstly, being pre-mixed, it eliminates the guesswork and potential inconsistencies that can arise when mixing your own sand and cement. This ensures uniform consistency and quality throughout the application. Secondly, its user-friendly nature means even those new to patio pointing can achieve professional-looking results.

Moreover, the compound often has added benefits, such as weed inhibitors, which prevent unwanted growth between the slabs. It also tends to be more resistant to the elements, ensuring longevity and reducing the need for frequent touch-ups. Lastly, its availability in various shades allows homeowners to choose a colour that complements their pavers, enhancing the overall aesthetic appeal of the patio.

Aspect	Brush-In Jointing Compound	Traditional Brush-In
Base Components	Ready-mixed sand and cement	Manually mixed sand and cement
Consistency	Uniform due to pre-mixing	Varies based on manual mixing
Application Ease	User-friendly, suitable for beginners	Requires more expertise for consistency
Additional Benefits	Weed inhibitors, weather-resistant	Dependent on mix and external products
Colour Options	Available in various shades	Limited to sand and cement's natural colour
Longevity	Often more durable due to consistent mix	Dependent on quality of manual mix

A table comparing brush-in jointing compound to traditional brush-in grout.

3. Two-Part Epoxy Jointing Mortar

The two-part epoxy jointing mortar presents a sturdy alternative for patio pointing. Renowned for its durability, it's apt for various surfaces, including driveways. This method is centered on the amalgamation of two elements: a resin and a hardener, which together produce a mortar that fills the gaps between paving slabs.

To utilise this method, firstly ensure the patio surface is clean, with all gaps between slabs free from debris or loose materials. Given the viscous nature of the mortar, it's vital to prevent any seepage from open edges. This can be achieved by either haunching the edges or using putty to seal the gaps. The entire patio area should be dampened and kept moist during the application to delay the mortar from setting prematurely.

Once the surface is prepped, mix the two components of the mortar as directed by the manufacturer. The mortar can then be applied to the gaps with a squeegee, ensuring they are filled thoroughly. The semi-fluid consistency of the product means it will naturally settle into the gaps without the need for trowelling. It's crucial to wash off any surplus mortar from the paving slabs before it dries. After the mortar solidifies, which typically takes between 24-48 hours, the patio is ready for use.

Aspect	Two-Part Epoxy Jointing Mortar	Traditional Brush-In
Base Components	Resin and Hardener	Sand and Cement
Durability	Highly durable, suitable for driveways	Varies, often less durable than epoxy
Method	Mix two components and apply with a squeegee	Brush dry mix into gaps and optionally wet
Setting Time	24-48 hours	Depends on conditions, often quicker
Surface Preparation	Clear gaps, dampen area, prevent seepage from edges	Ensure surface is dry, clear gaps
Finish	Semi-fluid, settles naturally	May require trowelling, can be crumbly

A table comparing epoxy jointing mortar to traditional brush-in grout.

The practice of dry brushing-in for filling paving joints often results in subpar, crumbling mortar that allows weed growth. This occurs because without pre-wetting, the dry mix does not properly hydrate and bond. Irresponsible installers favour dry brushing as defects appear after they leave. Conscientious contractors can achieve better joints by packing dry mix into pre-filled, wet "butter" mortar. This provides moisture to initiate curing and hardening if the dry mix integrates well. However, care must be taken when later spraying water, as the cement-rich dry mix on the damp paver surface risks splashing and staining - the very issue dry brushing aims to avoid. Overall, combining wet mortar and tightly packed dry brushing can produce quality paving joints, but the technique demands care to avoid defects defeated its original purpose.

What is the best mix for patio pointing?

The best mix for patio pointing typically involves combining 3 parts sand with 1 part cement. This mixture ensures both a cohesive and effective pointing solution for patios.

Should patio pointing be wet or dry mix?

For patio pointing, using a dry grout is often recommended, especially after laying an impermeable bedding layer. This method is particularly suitable for smooth pavers with consistent joints. However, it's worth noting that unless a high-quality grout is used, dry grouting might be susceptible to issues like cracking and weed emergence.

Is sharp or building sand better for patio pointing?

For patio pointing, both building sand and sharp sand can be utilised. However, a slightly dry building sand or plastering sand is often preferred. Using sharp sand might sometimes yield a rougher finish, especially in dry grouting scenarios.

Does sandstone paving need grouting?

Sandstone paving requires grouting to fill the gaps between the slabs, ensuring stability, preventing weed growth, and achieving a finished look.

Does porcelain paving need grouting?

Porcelain paving also requires grouting. Grouting not only enhances its appearance but also ensures the tiles are securely set and water doesn't seep underneath.

Which is the best grout for sandstone paving?

For sandstone paving, a flexible and weather-resistant grout is ideal. It's advisable to choose a grout that matches or complements the colour of the sandstone for a seamless finish.

What do you mix with mortar for a patio?

When preparing mortar for a patio, it's common to mix four measures of sand with one measure of cement. If the situation demands, a plasticiser can be added as per its specific instructions.

How much sand for block paving?

The average amount of sand you need per m² of block paving is 3.3kg for 50mm block paving, 4.5kg per m² for 60mm block paving, and 5.7kg per m² for 80mm block paving.