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Why use Polyurethane liquids?

Flat roofing is a massive industry in the UK with up to 35,000,000m2 of work forecast to be done in 2018 with steady growth predicted over the next 3 years. All in all, it is going to be a lucrative time for flat roofers! The choice of roofing materials available is extensive including felt, fibreglass, single ply and EPDM to name just a few. They all have their pros and cons.

Polyurethane liquid roofing technology has come on a long way in recent years and is now a really big player on the market and the reasons are really clear!

Ease of Application

One of the biggest benefits of Polyurethane liquids is how easy they are to apply. In many cases, all you really need is a roller brush. Some liquids are two component and need to be mixed before application, though many (including Hyperdesmo) are one component, pre-mixed in the tin. You just open it and go.

Not only that, many of them these days are very fast curing. The fastest 1-component systems can cure in as little as 4 hours. They need to be applied in the dry but, if rain does suddenly come in, 15 minutes after being laid the membranes are showerproof so your hard work won’t get un-done!

Detailing is also easy with liquids. You can apply it with a brush around any awkward shapes, upstands and roof furniture without having to cut anything to size or shape. This will save you an awful lot of time and hard work!

They’re also cold-applied. This has massive benefits as far as application is concerned. Without the need for any heat or flames they lend themselves extremely well to use on refineries, chemical plants, public buildings and even residential areas. Because you don’t need a hot works permit to use them you can get started on the work much sooner.


Many roofing materials require some on-going maintenance. Fibreglass, for example, needs to have a resin coating applied every 5 years or so. Liquids can be applied once and that’s it for up to 25 years! This isn’t a bold statement. They have the accreditation to back this up. It is a good idea to inspect the roof every 6-12 months, especially as it is a requirement of many warranties that the roof is looked at regularly. However, applied properly, these systems don’t need any further work as failures very rarely happen. The flexibility of the membrane can easily accommodate movement in the substrate (such as in boards, high rise buildings and even bridges) and many liquids have a memory element to them which ensures they return to their original shape after being stretched.

Seamless Membrane

They also cure with a seamless membrane. Other materials that require application in strips will have joints between them. This is nearly always a source of weakness and, over time, as the substrate moves, they become weaker and weaker until they eventually fail. By not having any seams, liquid membranes don’t have the

UV Stability

Many liquids are UV stable meaning they won’t degrade or breakdown through constant exposure to sunlight.

Easy repair

If a liquid membrane does get damaged, it isn’t difficult to repair. Simply clean and prepare the affected area and apply a fresh coat of membrane.


This is one of the huge benefits. We’ve had contractors tell us that they’ve been quoted up to £50/m2 for some materials. If you add just £15/m2 for your own labour costs that puts you at £65/m2 which makes you very expensive, even for a very large client. Polyurethane liquids can start from as little as £10/m2.

Not only that but, because of how quick and easy they are to apply, labour costs are reduced. You won’t be working as long. And with fast curing times, you won’t have to wait as long to go back to finish a job. You can be done in a day and move on to the next job!


PU liquids can be applied top virtually any roofing substrate. It sticks to almost everything. The only exception we’ve being able to find being glass, which you’d never apply it to anyway! Whether the roof is big or small it’s a great solution to your waterproofing needs. It can even be applied over existing roofing so you don’t need to rip anything up or dispose of any faulty roof materials. You simply clean the surface, seal the joints and visible cracks and just paint the required liquids over the top!

Whether you’ve used liquids in the past and had a bad experience or you’ve never used liquids before, now is a great time to consider them. The technology behind them is advanced a long way and there are now very few situations where they don’t offer a fast, affordable and long lasting solution to your roofing work.

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"Hyperdesmo was the ideal solution for the job. Quick and easy to apply and very reasonably priced too."

Les Smith

LS Roofing

I have used several Alchimica products in the past and I keep coming back to them. Reliable, outstanding performance and fantastic prices. Thanks!

Chris J

CJ Waterproofing

I used Hyperdesmo HAA and Particular on a tricky job which combined with the great advice provided by the team at Alchimica resulted in a successful outcome and a satisfied customer. Cheers!

W Simpson

Simpson & Son Waterproof & Damp Proofing

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