Tools & Equipment

The UK’s Best Sealants To Fix A Leaking Conservatory Roof

a conservatory roof with blue sky and clouds in the background
Written by Jonathan Sweet

On the right day of the year, there’s no room more comfortable and calming to relax in than the conservatory.

However, even a small leak in the roofing can develop into a considerable issue if left unchecked, so it’s better to nip the problem in the bud rather than let it rain on your parade to a much higher degree in the future.

That’s because a small leak can lead to far more serious concerns, including a build-up of mould, mildew and condensation, potentially endangering the quality of the air that you, your family and your pets breathe and damaging walls, carpets and furniture. Of course, an untended leak can also deteriorate into a far more serious structural issue, so whatever you do, make sure you don’t leave the leak to its own devices.

For those keen DIYers who want to tackle a leaking roof themselves and who are fairly confident that an inadequate sealant is to blame, there are plenty of options that are freely available to buy online or in home improvement stores. When choosing a product to meet your needs, you should look out for an industrial-strength cream, spray or tape which safeguards all manner of different materials and which provides a long-lasting assurance that your roof will be sealed. Depending upon the size of your conservatory and the size of the leak, the volume or size of the sealant may also be a factor, while price can never be discounted from such decisions – even though it’s best not to cut corners for such a serious issue.

We’ve analysed the wide array of products available on the market and have picked out our personal favourites, based upon their own unique strengths and flaws. By perusing the buyer’s guide below, you should be equipped to make the best decision to stop your conservatory roof leaking without having to do any of the legwork.

Last update on 2021-01-07 / Affiliate links / Images / Pricing from Amazon Product Advertising API

Our preferred choices are as follows: 

Best Pick: Smart Leak Stop Spray & Seal

Incredibly easy-to-use spray stops leaks in a matter of seconds.

Cost: £19.95

When it comes to fixing a leaking conservatory roof, things don’t get much more straightforward than the old point-and-shoot technique offered by an aerosol spray. This product allows you to apply a sprayable mastic sealant directly onto the affected area, immediately forming a watertight seal.

The area must be cleaned thoroughly and allowed to dry before using the spray, which in an area plagued by leakages can be a tricky proposition – but not an insurmountable one by any means; all that’s required is the proper forward planning. After that prep is taken care of, the job couldn’t be easier.

The 500ml size of the can means it packs a fair amount of sealant as well, so it can be stored away and used for other jobs in the future. As well as being suitable for patching up leaky roofs, it can also handle window frames, drainpipes and any other number of household nooks and crannies.

One complaint from users is that although the manufacturers claim the spray to be clear in colour, it can come out yellow. This is obviously a problem if it stains the surface upon which it is sprayed and can lead to cosmetic damage, but in terms of functionality, it can’t be beaten.


  • Incredibly easy to use and immediately effective
  • 500ml can means it can serve multiple purposes around the home
  • Versatile and reliable


  • The spray may come out as yellow rather than clear, thus discolouring surfaces
  • Not suitable for larger apertures
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Value Pick: Everbuild Weather Mate

Robust, resilient and incredibly versatile, this sealant is engineered to stand the test of time even against the harshest weather.

Cost: £6.74

If you’re looking for a heavy-duty, all-purpose sealant at a price that won’t break the bank, look no further. The Everbuild Weather Mate employs an advanced isocrylic formula which serves as an effective sealant and adhesive, even when subjected to extreme weather conditions.

Regardless of which type of surface you wish to secure, whether it be asphalt, lead or galvanised steel, the Weather Mate has you covered. It’s temperature-resistant anywhere between -25°C and 95°C, which in the UK is far beyond the scope of whatever you’re likely to experience. Rain, hail or shine, it’s up to the task of plugging leaks and stopping gaps.

It has also been specifically designed to retain its flexibility over a long period of use, which is ideal for areas of the home that are particularly susceptible to expansion and shrinkage such as the seals of windows, doors and conservatory roofs. It’s also available in three different colours (white, black and clear) so that you can match it to the surface upon which it will be applied – and even paint over it after the fact.

One slight setback might be that the product requires a sealant gun tool in order to be properly applied, but that’s a common occurrence among such sealants. It’s also 295ml in size, so might not be suitable for really large jobs, but will suffice for most leakages or cracks around the home and is affordable enough that buying more than one isn’t a major concern.


  • Multi-purpose sealant suitable for all manner of surfaces and locations
  • Extremely resilient under all kinds of inclement conditions
  • Available in three colours to match the décor of your home


  • Requires the use of a sealant gun, but that’s not unusual
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Fowong Butyl Tape For Roof Repair

Super adhesive tape will stick to any surface and stop leakages immediately.

Cost: £14.99

If it’s more of a flashing or panelling problem than a sealant one, this Fowong butyl tape might be the solution. It works by creating a watertight seal with the surface to which it is applied, allowing no moisture to permeate through and fixing the leak in one fell swoop.

The tape is comprised of 1.5mm-thick butyl rubber, which is protected by a backing film to prevent it from sticking to unwanted items. Its self-adhesion properties will come into play once the film is removed and the tape reaches a temperature of 10°C – but just make sure you have it in the right position, because once it’s stuck, there’s no unsticking it! As long as it’s applied to a clean, dry surface, it’ll stay in place and ward off the ingress of water for years and years.

Suitable for use in environments between -15°C and 45°C and capable of withstanding torrential rainfall, sleet, snow or anything else that Mother Earth can throw at it, this is a great practical solution to repairing damaged panels or insulating the flashing between the conservatory and the house. However, it should be noted that the tape is quite wide, silver in colour and could create an unsightly appearance if applied to transparent parts of the conservatory roof.

The fiddly nature of the tape’s application may put some less confident DIYers off and it’s true that meticulous planning is vital, since using the tape incorrectly can result in a messy situation that’s difficult to rectify. However, following the instructions to a tee will invariably result in excellent outcomes.


  • Ultra-strong adhesive will stick to any surface and form a watertight seal
  • Long-lasting and affordable


  • Improper application of the tape may result in an undesirable and irreversible outcome
  • Silver tape is conspicuous and not easily painted over
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Unibond Outdoor Window & Frame Sealer

Flexible and waterproof sealant suitable for a variety of different surfaces.

Cost: £9.70

As with the Everbuild Weather Mate mentioned above, this Unibond sealant is specifically designed to seal the gaps around window frames, door jambs and roof panels.

Although not quite as flexible as its counterpart, it can be used on a wide variety of materials including polycarbonate, wood and metal, meaning it’s suitable for most home conservatories. It also won’t stain more sensitive surfaces such as marble and natural stone, while the fact that it is odourless means that there is no need to avoid the area for days after it has been used.

Again, you will require the use of a gun, but the cap and nozzle which comes with the product make it straightforward to use. Providing it is applied to a clean, dry surface, it should be touch dry within 20 minutes of application and fully cured within 24 to 36 hours, thus providing a watertight seal that will withstand the deepest of Great British winters for years at a time.

All in all, it’s an excellent product that’s easy to use and will provide a watertight seal within a matter of hours – it’s just not quite as impressively buccaneering as the Everbuild alternative.


  • Suitable for application to many different surfaces, including more sensitive ones
  • Impressive watertightness properties that hold up over time


  • Requires the use of a sealant gun (but again, this is fairly standard)
  • Not quite as versatile or as resilient as the Everbuild competitor for a similar price
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Dicht Seal Fix

Unique in that it can be applied to wet surfaces, this ingenious sealing compound is easily applied with the stroke of a brush.

Cost: £14.19

In contrast to all of the other options on this list, Dicht Seal Fix is applied using a simple paintbrush or spatula. It can also be applied to wet surfaces and still instantly provide a watertight seal, making it quite unique and the premium choice for certain jobs.

The consistency of this asbestos-free, bitumen-free and tar-free substance upon opening is akin to an incredibly thick grey sludge, filled with tiny hairlike fibreglass elements. But give it a thorough stirring and it’ll do your brush’s bidding without too much fuss, although the job can be a messy one and you’ll likely end up with very dirty implements at its conclusion.

As well as fixing the seals on a leaky conservatory roof, it is also adept at papering over cracks in pretty much any material – be it cast iron, plastic, wood or cement – of up to 10mm in width. Didn’t get the desired results at the first time of asking? Simply apply a second coat and wait for the sealant to do its thing.

Be warned, however: upon drying, the sealant takes on a fairly dark colour, so exercise caution when applying it to surfaces that will be open to public view. But for a 375ml tin which can serve you well on multiple occasions, it’s a very affordable package.


  • Very strong sealant can bridge apertures of up to 10mm in width in most materials
  • Can be applied even when the surface is damp or wet
  • Use of brush or spatula allows access to hard-to-reach places


  • Application can be a difficult (and very messy!) process
  • Any implements used to spread the substance may well be useless after the fact
  • Dark colour can make it unsightly to public view
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Tips On Fixing A Conservatory Leak

The first step to fixing a leaky conservatory roof is determining where the leak is coming from and what caused it. There are many reasons why your roof might spring a leak: damaged panelling, improper flashing connecting the conservatory to the main building, faulty guttering outside the structure or general wear and tear over time are just some of the issues to consider.

This last factor is probably the most common cause of a leaking roof, manifesting itself in a tired sealant which no longer does its job in keeping the conservatory watertight. Thankfully, it’s one which is fairly easy to fix and can be accomplished by any competent DIY enthusiast. However, you should be aware that many home insurance policies can become invalidated by undertaking work yourself, so only proceed if you’re confident in your own abilities to complete the job well.

After identifying a defective sealant as the problem, you should carefully remove it with a sharp utility knife, making sure you get rid of as much of the old substance as possible. Then, take the sealant of your choice and fit it to a sealant gun tool, before applying a new bead in the place of the old one.

Alternatively, if you are using a spray, clean the affected area as best you can to remove all dust or other debris, then make sure it is completely dry before applying the sealant. Shake the can well before use and spray it directly onto the desired surface at a distance of at least 25cm. Do not overdo things as this could lead to discolouration or even compromise the structural integrity of the seal. It’s preferable to apply several thinner coats than one excessive one.

Finally, tape should only ever be used to patch up a physical hole in the panels or joins of your conservatory roof. While heavy-duty tapes can provide long-lasting watertightness, they can be unsightly and so may only comprise a temporary solution.

If none of the above sealants offer the solution that you need, it may be time to consider calling in the professionals. Catch the problem in the bud early enough and it’s unlikely to be overly expensive, but leave it to fester and you could find yourself faced with a bill worth several thousand pounds – so address the issue sooner rather than later.

About the author

Jonathan Sweet

Jonny is an avid writer with a background in tourism, film and literature, but has a penchant for penning articles on all kinds of topics. He's always considered himself an environmentalist to some degree, but in recent times he has found himself shining a greater spotlight on his daily lifestyle choices and how the tiny changes he can make to his routine can have a cumulatively significant impact on the planet.

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