Laying a new road surface or resurfacing an old, the weather will always be a key consideration, and as you’d probably expect, the same goes for pretty much any work involving the ground. With roads, the conditions in which you lay the asphalt or tarmac can have a notable impact on the finished product. But can these materials be laid out in the rain at all? Will they even set correctly? In this guide, we answer the common questions regarding whether you can surface roads and other surfaces in the rain.
- Can you lay asphalt or tarmac roads in the rain?
- Why can’t you pave roads with asphalt while it’s raining?
- Why can’t you tarmac roads while it’s raining?
- Should you tarmac a surface in the rain?
- Should you lay asphalt in the rain?
Can you lay asphalt or tarmac roads in the rain?
Laying asphalt or tarmac in the rain is possible, but it’s not recommended due to the likelihood of the surface not being able to bond properly — leading to a subpar finish. This is particularly applicable to cold-mix asphalt because the mixture already contains some water, adding any more will cause immediate issues.
Essentially, if the rain is only light, you can proceed with the job as planned. A fine sprinkling of precipitation here and there isn’t likely to affect the end result, although it might make the job a little more tricky.
If the rain picks up, however, or lasts longer than a few minutes, you’ll have no choice but to bring the work to a halt. If too much water builds up on the surface, the new surface simply won’t be able to bond.
Why can’t you pave roads with asphalt while it’s raining?
There are generally three layers of asphalt on a stone base when it comes to constructing roads in the UK. Asphalt is made of a viscous petrol mixture, which means it’s oil-based. Rain brings the oil to the surface of the asphalt in pavings and roads when it rains, meaning the road will take much longer to cure.
Delays
Damage that can occur if you lay asphalt paving or roads in the rain include delays. If it’s a busy road, this could cause days or weeks worth of delays due to an unusable road surface.
Structural Damage
If water displaces the oil in the asphalt road surface, this can lead to structural damage like cracking. These issues can seem small at first, but they can quickly grow to become larger issues, like the dreaded potholes we get across roads in the UK.
Compromised Integrity
Asphalt paving is done when the asphalt mixture is extremely hot. When it rains, the asphalt cools far too quickly. If the base is recently laid, rain can create steam between the top layer of the road and the base. Over time, as the steam cools, water gets trapped between the base and top layer of asphalt.
Why can’t you tarmac roads while it’s raining?
Tarmac is made up of a mixture of aggregate materials and tar, a black viscous liquid. Tar reflects water just like oil does, so a tarmac road surface being laid in the rain can lead to issues similar to those with asphalt.
Longer Curing Process
Water in the mixture can disrupt the tarmac setting process, leading to delays. If it’s a busy road being resurfaced, this could result in the road being out of use for even longer.
Structural Damage
If rainwater becomes trapped in the new road surface, it can compromise its durability, leading to cracks and the formation of potholes. This could be a result of traffic pressure or the freeze-and-thaw cycle, gradually weakening the surface.
Poor Bonding
Tarmac is laid as a hot liquid, so when it rains, steam forms as the tarmac cools. This trapped steam between the base and top layer not only affects the surface appearance but can weaken the structure.
Should you tarmac a surface in the rain?
While it is possible to do so, it’s not recommended to tarmac any surface in the rain. Water mixing with the tarmac interferes with the bonding process, quickly causing issues with setting and later down the line. Even if it isn’t raining at the time, waiting to lay it on a completely dry day will ensure the best finished result.
Should you lay asphalt in the rain?
Unless you absolutely have to, no, you shouldn’t pave any surface with asphalt in the rain. Rainy conditions should be avoided where possible, as they can cause complications and, ultimately, set the road or driveway laying project back.
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If you’re looking for further advice or would like to get a road surfacing quote, get in touch with us today. Professional road surfacing contractors covering the entirety of the UK, we serve both commercial and residential clients. For a free, no-obligation quote, speak to our team today!
