Micro-asphalt is a material used to provide a new surface layer to an existing asphalt footway. It contains bitumen emulsion, fine aggregate, cement, and water. It is a surface treatment applied over an existing footway surface, without the need to dig out the existing surface first. This differs from resurfacing which removes and replaces the old surface.
What happens in advance of the works
Some preparation work will take place ahead of the main resurfacing work:
- A month ahead – the footway will be sprayed with weed killer. This will sometimes happen twice where there is heavy weed growth.
- Immediately prior – overgrown verges and hedges will be trimmed back so the full footway surface can be accessed.
- Immediately prior – ironwork (stop valves, manhole covers and so on) will be raised by about 10mm. This will sometimes take place alongside rather than ahead of the main work.
What happens on the day of works
On a typical day we will do the following:
- Pressure wash and sweep the footway surface.
- Mask ironwork, kerb stones and the edges of private property with tape.
- Close a section of footway to pedestrians and the adjacent road to parked vehicles using traffic management (cones, barriers and so on). Alternate pedestrian access will be provided and vehicles will still be able to drive past the work location as normal.
- Lay a rough layer of micro-asphalt material to fill in dips and holes if required.
- Lay a base coat of micro-asphalt by hand over the entire footway surface.
- Lay a second coat of micro-asphalt by hand on top of the first, either on the same day as the base coat or the following day.
- Remove the traffic management and open the area back up to pedestrians and start again for the next section.
- When the entire footway has been treated, remove tape used to mask ironwork, kerbs and private property.
Will the weed killer cause harm to me or my pets?
No, the weed killer is mixed with water to dilute it, so presents no risk to humans, pets or wildlife even if directly ingested, for example by licking a sprayed weed.
It is sprayed only at ground level and will be completely dry within about 30 minutes to an hour of spraying, so the likelihood of coming into contact with the weed killer is very low.
What will happen to vegetation from front gardens that overhangs the footway?
Under the Highways Act, it is the legal responsibility of homeowners to make sure any vegetation from their property does not obstruct a highway. As such, homeowners must not let vegetation grow over a footway. More details on what homeowners need to do is available on our tree and hedge maintenance page.
Footway micro-asphalt works need clear access to the whole footway surface. We will send letters out in advance of the work asking residents to cut back any vegetation that is blocking the footway to their boundaries. If this hasn’t been done by the time the work begins, we will cut back any overhanging vegetation ourselves.
However, we may not take as much care as residents in doing this, so if residents are concerned about the appearance of their vegetation, it is strongly recommended they carry out any cutting themselves in advance of the work.
Can I still walk along the footway during the work?
In most situations, pedestrian access along a road will be maintained throughout the work. Where there are footways on both sides of a road, only one side will be closed at a time, so the opposite side can be used as normal. Where there is only one footway, a temporary walkway will be provided in the road for pedestrians to use.
In rare occasions where there is no opposite path and no space for a walkway, the footway will be closed and a signed diversion route will be in place, directing pedestrians to the shortest alternative route around the work.
Can I access my property during the work?
Pedestrian access to properties and vehicle access to private driveways will be maintained throughout the works. However, when work is taking place immediately outside your property access will be limited.
The workforce on site will give advanced warning of when this will be and if you have a specific need to access your property at a certain time (appointments to keep, expecting a delivery) please speak to the workforce who will be happy to assist.
How does micro-asphalt work?
Water penetrating lower levels of a footway causes potholes and other structural failures.
Micro-asphalt corrects minor defects in the surface and seals it, preventing water reaching these lower levels. Defects that micro-asphalt addresses include:
- non-structural cracks
- surface potholes
- utility works
- minor undulations
- previous repairs to the footway.
Why is water collecting on the new surface where it wasn’t before?
As micro-asphalt creates a waterproof seal on the surface, water can collect on the surface where it would have previously drained through cracks in the surface. Such situations usually only result in small amounts of water collecting and are not considered a fault with the newly laid material.
Why use micro-asphalt instead of normal resurfacing?
Micro-asphalt and normal resurfacing serve different purposes.
Laying micro-asphalt is a preventative measure. We lay micro-asphalt to a footway before it suffers significant damage to extend it's life. We may use it in situations where a footway surface might still look to be in reasonable condition.
When used at the right time, laying micro-asphalt delays the need to do more significant work minimising disruption to residents and road users.
Resurfacing takes place when the footway has significant or structural damage already, requiring the damaged material to be removed and replaced. Because of this, resurfacing works are a bigger job than surface treatments and cause more disruption to residents and road users.
What are the environmental considerations of using micro-asphalt?
- With the existing footway surface left in place, reduced working times and no need for disposal of materials means work produces less carbon emissions.
- There are no waste materials needing recycling or disposal.
- The quantity of natural materials used is small and there are less carbon emissions from transport because micro-asphalt is used in thin layers.
- Micro-asphalt is a 'cold mix' material. It's safer to use than 'hot mix' materials and there are energy savings as there is no need for heating during producing and transporting.
- Micro-asphalt is not produced using dangerous chemicals, so contact is safe for humans and wildlife.
- Applying a treatment is a smaller job than resurfacing, saving energy and reducing carbon emissions.
- Applying micro-asphalt extends the life of a footway, avoiding the need to carry out much more energy intensive repairs.
How long does a micro-asphalt treatment last?
This surface treatment typically prolongs the life of a footpath by up to 10 years, but it can last significantly longer in the right situation.
Why does it look coarse and unfinished?
This is normal. Micro-asphalt is unusual in that it takes some time to cure and bed in. It's appearance changes as this occurs. When first laid, it will look very dark, feel soft underfoot and have a rough texture.
During bedding in, the surface lightens in colour, solidifies and becomes smooth. In the end, it will look like a typical path. The bedding-in process takes around three to six months, but can vary depending on weather conditions. Areas used by lots of pedestrians will bed-in noticeably quicker than those which are lightly used.
The new surface has a strange pattern on it. Is this normal?
Yes. As the new material is hand-applied, it will naturally feature a wave-like pattern caused by the hand tools used to lay the material. This pattern does not affect the safety or performance of the new material and will reduce over time as the material beds in.
Marks are occurring on the new surface. Is this normal?
Yes. The new material is soft when laid and therefore marks easily. The most common causes are cars, bicycles and wheelchairs leaving tyre tread imprints on the surface.
These marks can look quite significant, but they usually do not impact the strength or longevity of the new surface and will fade with time as the material beds in.
The only way to prevent marks is to close the footway for the whole bedding-in period which is not a realistic option.
Can I walk or drive on the new micro-asphalt surface?
Yes. The workforce will leave the traffic management in place until the surface is safe to walk on, so as soon as the traffic management has been removed the footway can be used as normal. This usually takes around 20 to 30 minutes following application.
If walking on the surface very shortly after it has been laid, please check footwear before entering buildings to prevent any loose material inadvertently being brought inside. Please also keep an eye on pets (particularly cats) during the works. Whilst every effort is made to keep animals clear of the works, they can occasionally wander on to the wet material and then track that material back into houses.
Vehicles can also drive across new surfaces to reach private driveways or garages as soon as the traffic management has been removed. To prevent damage to the new surface please try and avoid turning the front wheels, especially whilst stationary, on the new surface for the first few days after work finishes.
A stop valve or manhole cover is still buried under the new material, is this right?
All ironwork is masked up prior to the new surface being laid. Normally, all ironworks (stop valves, manhole covers and so on) will be uncovered by removing the tape as soon as the new surface is laid. Occasionally, some ironwork may be left covered for up to a week longer to avoid damaging the new material when the tape is removed.
If any ironwork remains covered beyond this, please let us know as it may have been left covered in error.