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Learn How to DIY Renovate

Learn How to DIY Renovate
Learn How to DIY Renovate

DIY Tutorials

DIY Tutorials
DIY Tutorials

Replacing the Conservatory Roof

Replacing a Conservatory Roof

This job is well and truly overdue. Our conservatory roof has been leaking pretty much since the day we moved in, almost two years ago. I know how bad that sounds, really I do. See, it wasn't that bad initially... You already know where this is going don't you? A small leak, turns into a bigger leak, which eventually turns into a massive repair job.

The reason we didn't repair it straight away (although we should have!) was because we had always planned to replace the conservatory roof. It was pretty obvious it was old and not working as well as it should have been. It blew up and down in the wind, screws were clearly loose, water was seeping in, it was dirty, full of condensation, the list just went on. But over this last winter, that leak had become pretty darn bad. We ended up having to leave buckets in the conservatory permanently, ready for rain to fall at any moment. We knew we needed to get this done before going away later this year, or else we would risk coming home to a flooded conservatory. With the warm weather on the horizon and more daylight hours, now seemed like the right time to get this job done.

old polycarbonate roof
dirty conservatory roof

I mentioned in my last post about the plans for this room, how I would have loved the opportunity to have extended through properly and had this room as beautiful modern glass box. But alas, our money does not stretch that far, so this conservatory renovation is quite a budget one and we're making do with what we have, which also means we're sticking with polycarbonate roofing. Yes it's not that pretty and not that great for insulation, but it's the best option for us financially and for a cheaply-built weak structure conservatory, even if we did have the money, adding £1000+ glass panels to a poor timber structure, is by no means a good investment.

Polycarbonate roofing isn't as bad as it used to be by any means! It's positives are that it's lightweight, tougher than glass and now with multi-wall layers, its insulation properties are far better than they've ever been too! The original roofing in this room was about 5mm thick with just a top and bottom layer of polycarbonate combined, however our new roof is 25mm thick with multiple walls (I couldn't even count how many!) between the two outer layers. You can see how different the old and new stuff really is!

old versus new polycarbonate roofing
clear polycarbonate transparency

Polycarbonate roofing comes in three different shades, clear, opal or bronze. Personally, I'm not really sure why anyone would want bronze - but we've opted for clear. We need as much sunlight to enter this room as possible so that it brightens up the dining room beyond which has absolutely no direct sunlight. Our conservatory only gets direct sunlight through the morning so we've never had problems with it turning into a sweat box either, it's always just been pleasantly warm. For conservatories constantly in direct sunlight, opal is the best option as it gives a little bit more shade to the room and will cool it down a touch.

The polycarbonate we purchased was from Sheet Plastics which we ordered cut-to-size. I didn't find much price-difference between any sites really, but sheet plastics had the best delivery cost and they stocked the glazing bars a touch cheaper too.

Step 1 - Removing the Old

Of course every job starts with some demolition and this was no exception. We weren't too delicate about getting the old roof off, so we were able to simply cut through sections of the polycarbonate. Other than a couple of difficult to reach screws, everything popped off quite easily and before we knew it, the conservatory was left very exposed! Even though I had checked the weather that morning, in true British fashion, it rained. Only a little, mind - but it was rather chilly and I could definitely have picked a better day for this job!

removing the conservatory roof
taking down polycarbonate roof
conservatory without a roof

{Gutter Maintenance}

Remember this job I mentioned, erm, a few, several months back? Yes, well er - this is another of those jobs we decided to put off. This overflowing gutter with a plant growing out of it was causing damp in the smallest bedroom and was in desperate need of a fix. It's particularly poor location meant we were unable to get a ladder to it with the conservatory in the way. We attempted to fix it though the smallest bedroom window, we even cracked the hoover out and added a rather long attachment to it, all to no avail. We got a quote from a local gutter cleaning firm, who wanted £200(!!!!) for this job. So, we ended up putting it off until we could deal with it ourselves without the conservatory roof in the way.

cleaning hard to reach gutter

Grant doesn't like heights much, so this job was another one for me. I don't mind ladders, but it does take some getting used to if you don't use them very often. Obviously being up a ladder isn't difficult, but multi-tasking with tools and equipment is another matter. I did ask Grant for some photos for the blog, but er- this was his interpretation.
view up a ladder
girls on ladders

The first isn't quite what I had in mind, ha! Anyway, I fished out the plant really easily and gave the rest of the gutter a clear out too. Then I took some mortar up to fill some of the gaps in the brick and finally I installed a new gutter clip to keep everything nice and secure. I'd love to say the problem is now fixed - it certainly does drain properly, however some time later it became apparent the top gutter was actually also over-shooting the hopper during really heavy rain. So whilst we've alleviated most of the problem, it does still need attending to and is causing some splashing down the side of the house. We have a couple of ideas for reaching it without taking the conservatory roof back off, but this was somewhat hugely frustrating.

plant from gutter

Step 2 - Laying Polycarbonate under Lead Flashing

For our new roof, the polycarbonate is butted up against the original part of the house as well as the  old kitchen extension. This means the panel on the right hand side is mostly secured under lead flashing. There was no need to replace the lead flashing, it simply lifts up allowing you to slot the new roofing underneath. Of course the old roof was much thinner, so it did take a little bit of a kerfuffle to get it slotted nice and neatly underneath. The lead flashing then be hammered back down over the new polycarbonate until it's nice and tight with  no  gaps. It really is that simple! Our lead flashing is mostly in great condition, but we suspected an overlap of flashing was the culprit of the original leak, therefore we purchased some self-adhesive flashing to lay over the top of the overlap to ensure there would be no leaks. Self-adhesive sounds really dodgy but it was highly reviewed on Screwfix so we've put our faith in it too! We've also added it along the original lead flashing and new polycarbonate just to be extra sure there would be no leaks there too. It's not the prettiest site, but it's all hidden by the gutter than sits on-top of the roof anyway.

using self adhesive flashing
fitting a new conservatory roof

Step 3 - Using Glazing Bars

In between every other length of polycarbonate roofing are some glazing bars. These hold the polycarbonate in place without having to use any screws or drill any holes into the actual roofing itself. The bar is screwed into the beams, making sure to use polycarbonate sealant on each hole to make double-sure no water can get through. The polycarbonate is then butted up against the glazing bar, making sure to leave a few mm gap for expansion. The top of the glazing bar pushes down onto the polycarbonate to seal it into the place. If done correctly and securely, the rubber seal will ensure no water ingress.

polycarbonate sealant
how to fit glazing bars

Step 4 - Installing F-Sections

After every roof panel is in place, the final job is to secure F-Sections at the very end of each roof panel to cover up the breathable tape. The breathable tape allows the polycarbonate to breathe and ensures no condensation can form inside, but the tape with lots of holes in, means it's liable to water ingress if not properly sealed up, but still being allowed to breathe! This where the F-sections are used, they simply fit over the ends and tidy everything up. We've also used another F-section on the very last glazing bar to providing something for it seal onto where there's no roofing panel.

how to fit f sections


  • Buy your polycarbonate roofing cut to size - cutting polycarbonate across the flutes with a manual saw will cause dust to be pulled into the flutes and will be a nightmare to get out. Having it pre-cut in a warehouse ensures your flutes will arrive dust-free and clean.
  • Ensure the panels are cut into smaller manageable lengths, ideally no more than 700mm wide and most definitely not one giant sheet (like our previous roof!). You'll need to be able to reach over the roofing to snap down the glazing bar, so it should at least be no more than an arms length wide.
  • Always install polycarbonate roofing with the flutes running downwards.
  • Make sure the dust breather tape is installed at the lowest point of the roofing (i.e. not under the flashing) - if bought cut to size, the other end will be a sealing tape with no holes.
  • Always use sealant on screw holes, we've used a specific polycarbonate sealant which is flexible and allows for expansion.

And there we have it - our new roof! It's not overly pretty or breathtaking, but is completely watertight, fit for purpose and does what we need. In sunshine the roof shines in a blue-ish colour. From the inside it can be too bright to look up at the roof in direct sunlight (this is why the opal shade is ideal for conservatories constantly in sunlight!) but our new roof has, for the first time ever, allowed a ray of sunlight into the dining room. There was actual rays! It's brightened up the dining room no end, feels a little warmer, looks much better and is a heck more practical too! No leaks!

It was really simply to do, didn't really require any major DIY skills, but it's definitely worth taking your time over, a job your really only want to do once with no leaks. Preferably a nice sunny day wouldn't go amiss too!

modern polycarbonate roofing
lean to conservatory roofing
transparent polycarbonate roof
new polycarbonate conservatory roof

What do you think? Have you/would you ever use polycarbonate roofing? Let me know what you think to it :)


(rounded to the nearest pound)

New Tools Purchased:

Materials Used:
Roofing £200
Glazing Bars £65
F Bars £20
Polycarbonate Sealant £6
Exterior Screws £6
Self-Adhesive Flashing £27

Total: £324

How to Replace Polycarbonate Roofing

1 comment

  1. Roof replacing is very important and necessary to do as it is the part of home that is directly get in contact with rain, snowfall and other things. So, maintaining it and getting it repaired is extremely important. Thanks for sharing this.


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