Questions to ask a Paving Contractor

Below are some important questions to ask your contractor and find out if he is quoting for paving that will last a lifetime or fail very soon. DO NOT ACCEPT THAT A CONTRACTOR KNOWS WHAT HE IS DOING. You have to live with your installed paving, not the contractor.

Just take a look at the below questions to see typical responses obtained from good, mediocre and poor installers.

Are you going to dig up any soil?

Soil decomposes and could cause paving to sag.

The best installers will always remove topsoil and replace it with a sub base or foundation layer, even for pedestrian traffic
This is more troublesome and will cost more.

“No but…”
Installers might only scarify soil and some will add cement in order to stabilise it. It is not as good as excavating and replacing soil with another material but is cheaper. Bear in mind that this method might hold risks.

They won’t dig out anything. They might compact the top soil if you are lucky. This is the cheapest way but your paving is bound to fail because natural material in topsoil decomposes.

Are you going to construct a foundation (sub base)?

You don’t want your paving to sag.
A foundation layer is standard practice throughout the world. Search the internet for paving installation advice and you will see this in any guideline, YouTube video, and “how to” website

Although the material is cheap, it costs money to have it delivered and to cart away the excavated soil.
Be prepared to pay more for this critical element of paving installation.

“No but…”
Installers might argue that South African soils are better than those found in other countries.
The point is, it is a gamble. The root of most paving problems is the lack of a foundation layer which leads to a host of problems.


“What is a sub base?”

Do you use a roller to compact the foundation (sub base)?

The earth moves and soil decomposes. This will cause paving to sag.

The best installers will use a roller or heavy plate compactor to compact their sub base or foundation.

“No but…“
I use a plate compactor.
Follow up question:
How big is your compactor?
Small compactors offloaded from the truck by one man is not recommended. This will not create sufficient compaction of the foundation layer.

“No. “
These installers might do no compaction at all. Your paving will fail if you don’t have a well compacted sub base.

Where is water going to flow and drain?

Water ponds only become bigger and create all sorts of other problems.

Good installers will always consider drainage and create the necessary falls with their foundation layer. In addition, the best installers would install drains when necessary.
It is a larger initial investment but you won’t have problems in years to come.

Experienced installers will be able to tell you where water will drain. They will not create slopes with bedding material. All slopes will be created before bedding material is installed.

We will see as we go along (but we use Spirit levels).

Will you draw pavers from different packs when installing?

There will be slight variances in colour between different batches and even packs of paving from any paving manufacturer anywhere in the world.

Good installers will draw pavers from different packs.
This will take longer and cost more.

“No but…“
Installers might say it is impractical and wastes time. It is true, but you won’t get variable patches in terms of colour.

“No. “
These installers won’t understand the concept.

How are you going to install the edges?

Because you don’t want your pavers to creep sideways it is critical to have solid edge restraints.

Good installers will bed their edge courses in concrete and haunch it with concrete. They will ensure that the concrete beds also retain the layers underneath the paving. They might also use kerbs to reinforce their edges.
This takes time and cost more.

We bed pavers on the edges in concrete.
Follow up questions:
Will the bedding be around 100mm thick?
Do you also haunch it with concrete on the sides?
If you use kerbs, are they also bedded in concrete and haunched with concrete?

We dig a trench on the edge and put cement.

Will you use a fixed or flexible method of installation?

Flexible paving installation is the globally accepted norm and when done correctly, it will last a lifetime. This method is specified by SANS 1200MJ, the official standard for the installation of segmented paving in South Africa. We recommend this method for SmartStone cobbles and pavers smaller than 222mm x 222mm in size intended to carry any vehicular traffic. Many installers however prefer to also install cobbles and driveway pavers according to the fixed method, especially on smaller areas. To be fair, it is sometimes better and carries less risk, especially when earthworks are not done according to our guidelines.

Fixed paving installations create a solid concrete slab with the pavers bedded on this slab and forming part of it. All SmartStone Flagstones (Pavers larger than 222mm x 222mm) should preferably be installed according to this method.

Most important though, is never to mix the two philosophies. In a fixed installation, use a concrete bed and cement or other fixed joints and a flexible installation use sand for bedding and jointing. Sand on one and cement on the other simply doesn’t work.

Just click on the below questions to see typical responses obtained from good, mediocre and poor installers.

When doing a Flexible installation:

Do you use screeding rails with a plank or similar to even out bedding sand?

You want paving to be level. Again, this is something that could be “Googled”. Screeding of bedding sand with guiding rails is always done by contractors throughout the world.

The specification states that bedding sand should be 25-35mm in its compacted state. To achieve this one should screed 30mm-40mm of sand which will then compact to the correct thickness once pavers are installed.
Screeding with rails appears to be more time consuming.

“No but…“
Some installers will use a plank or spirit level, screeding in a circular motion. Although this is better than no screeding at all, you will never achieve the consistency of rails. Consistent thickness of bedding material is critical for a good installation.

Huh? “
These installers will rake sand and start packing pavers on it. They might “level” sand with a brick before placing it. These installers will generally save on sand and only spread out sand to a thickness of 10 or 20mm. Be sure to see many high and low pavers, broken pavers, water ponds and a failed site within a few years.

Do you use a plate compactor (with a protected plate) or roller (with vibration switched off) to level pavers once they are laid and bedding sand is still moist?

You want a smooth, even paved surface.

“Yes” Good installers will carefully level pavers with equipment mentioned while bedding sand is moist. When you wait too long, bedding sand will dry out and pavers won’t “seat” properly and even.

“No but we bring the compactor when we grout. (This will result in an uneven paved site.)

“No” They will probably not compact pavers at all. This will result in certain paving failure.

Will you use sand to grout the paving?

Grouting sand creates interlock between pavers and prevents sagging and creeping. You further want to distribute loads to the layers underneath.

The best contractors will use a specially graded paving grouting sand because it offers the best interlocking capabilities.
This will cost more.

Many contractors will want to use cement and sand or a cement slurry. This could be disastrous if pavers are bedded on sand, as you now create a solid “slab” that doesn’t distribute the load to layers beneath the paving.

Incompetent contractors will use the cheapest sand available even if it is red and stain your pavers. They might also use a cement slurry which will never be consistent and most probably also permanently stain your pavers. They will not understand the principle of distributing loads to layers beneath the paving.

When doing a Fixed installation:

Will you bed my pavers on concrete?

You want paving to be level. Again, this is something that could be “Googled”. Screeding of bedding sand with guiding rails is always done by contractors throughout the world.

The best installers will individually bed flagstones on slightly moist concrete and tap them down with a mallet. They will touch and feel to ensure pavers are level.
This is troublesome and costs more.

Some contractors use a wet and fluid concrete slurry. This method might stain pavers and make a mess.

Incompetent installers will install pavers with grouting gaps larger than 5mm on a sand bed.

How will you ensure the flagstones don't come loose from this concrete bed?

The earth moves.

Good Installers will use a bonding liquid, tile adhesive or similar to ensure flagstones stick to the concrete bed.
This will cost more.

Some contractors claim that wetting the paver achieves better bonding. It is better than nothing, but not fool proof.

We use cement.

Will you use sand to grout the paving?

The earth moves.

The best installers will use imported grouting material made especially for flagstones.
It is expensive, but works.

Good contractors may make a moist (not wet) mixture of one part cement and three parts building sand and work it into joints individually, carefully sponging it clean.

A slurry swept into joints is the quickest way but is bound to fail. It will pop out and crack in time. It is also very likely to permanently stain your paving. This method is also very likely to cause “Picture framing” of pavers.

SmartStone installation guidelines to serve as instruction to your contractor.

The most important things to understand about paving.