DIY: Replacing and Fitting A Polycarbonate Conservatory Roof

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 – but it wasn’t that bad initially. But you probably already know how it goes – a small leak, turns into a bigger leak, which eventually turns into a massive repair job. So, replacing the polycarbonate roof was the next big DIY on the list for us.

We chose to replace the conservatory roof rather than repair it because the old polycarbonate we had was so thin and uninsulated, it provided no protection for the room and it felt like you were outdoors! It was also so flimsy (you could literally see the whole roof blow up and down in the wind!), it was full of condensation and generally just a bit crap. It needed replacing!

In an ideal world, I would love to be able to extend the kitchen/dining room into the conservatory and re-build it as a beautiful modern glass box. But let’s be real, our money simply does not stretch anywhere near that far. So this conservatory renovation is going to be quite a budget one and we’re mostly making do with what we have!

This means we’ll also be sticking with polycarbonate roofing, but a new modern one! Polycarbonate isn’t brilliant for insulation, but it’s the best option for us financially and even if we did have money for proper glass, the structure of our conservatory probably wouldn’t be strong enough to take the weight anyway!

The positives of polycarbonate roofing is that it’s lightweight, tougher than glass, and newer modern polycarbonate roofing has multi-wall layers, which means its insulation properties are far better than they’ve ever been! The original polycarbonate roo in this room was about 5mm thick, however, our new polycarbonate roof will be 25mm thick with multiple walls between the two outer layers. You can see how different the old and new stuff really is!

Polycarbonate roofing comes in three different shades, clear, opal or bronze. Personally, we’ve opted for clear as we need as much sunlight to enter this room as possible so that it brightens up the dining room 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 sweatbox 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 made-to-size. I didn’t find much price-difference between different websites, but sheet plastics had the cheapest delivery cost and the glazing bars were also slightly cheaper too. So anyway – I thought I’d share how we removed and replaced the new polycarbonate roof!

Step 1 – Removing the Old Polycarbonate Roof

We weren’t too delicate when it came to removing the old roof, we basically just cut and yanked it out! Other than a couple of difficult to reach screws, everything popped off quite easily and before we knew it, the conservatory was left fully 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 we could definitely have picked a better day for this job!

{Gutter Maintenance}

Whilst the conservatory roof was off, we took a little detour and put a ladder up to fix the overflowing gutter which had a plant growing out of it (eek!). It’s been causing a bit of damp in the smallest bedroom, so was in desperate need of a fix.

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. 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.

I cleaned the plant out from the gutter and then repointed a small bit of brickwork before reattaching a new gutter clip to keep everything nice and secure! I’d love to say the problem is now fixed, however, we later realised the overflowing gutter wasn’t entirely caused by the plant. The top bit of gutter was basically overshooting the hopper. 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.

Step 2 – Laying The New Polycarbonate Roof under Lead Flashing

As our new roof is butted up against the original part of the house as well as the kitchen extension (to the side), we needed to secure it underneath some lead flashing. Obviously we still had the lead flashing from the old roof, so we kept that in place and simply slotted te new roof underneath, re-moulding it.

The old roof was of course much thinner, so it was a little bit of a kerfuffle to get it nice and tight with no gaps and we did use some self-adhesive flashing in a couple of spots where the lead overlapped, just to be on the safe side!

Step 3 – Using Glazing Bars To Install the Polycarbonate

The polycarbonate roof we ordered was cut into three equal lengths (rather than one giant sheet). We felt this would be easier to install and allow for more secure fixings (unlike the old roof which was mostly one sheet!). To install the three separate sheets, we needed two glazing bars which would go in-between each sheet. These are made up of two parts – a bottom piece and a top piece which slot together.

Once we had placed the first polycarbonate sheet in place, we then screwed the bottom section of the glazing bar alongside the polycarbonate sheet (leaving a couple of mm for expansion), and affixed it straight into the beams. We also used some sealant each screw to make double-sure it would be watertight.

Once the bar has been secured properly, the top piece of the glazing bar then pushes down onto the bottom piece to seal the polycarbonate into place. If done correctly, the rubber seal on the top piece will ensure no water ingress. If any small amount of water does get underneath, it should run off along the bottom section of the glazing bar and drip off at the front of the room.

Step 4 – Installing F-Sections at the Front

We repeated step 2 and 3 for each length of roofing until the conservatory was completely covered. The final job was then to secure some F-sections at the front and the side of the exposed sides, which basically just covers those cut edges! At the front, you should have a breathable tape over the edge as well (this has lots of holes in and allows condensation to escape), so the F-section also stops rain getting into those holes as well, whilst still allowing the polycarbonate to breathe.

To attach the F-sections, they basically just slot onto the polycarbonate! You’ll need to use a rubber mallet to make sure they’re properly on – but there’s really not much else to it!

And there we have it – our new roof! It’s not overly pretty or breathtaking, I’ll admit, but it’s completely watertight, fit for purpose and does what we need. I love how clear it is (unlike the old dirty roof!) and for the first time ever, it’s allowed a ray of sunlight into the dining room, brightening up the room no end! It’s also much warmer and you’ll be pleased to know we’ve had ZERO leaks! A job well done I say 😉

TIPS:

• Buy your polycarbonate roofing cut to size – cutting polycarbonate across the flutes with a manual saw will cause dust to be pulled inside the walls of the polycarbonate roof and will be a nightmare to get out. Having it pre-cut in a warehouse ensures the inside of your polycarbonate 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 as well.
• Always install polycarbonate roofing with the flutes running downwards.
• Make sure the breathable 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 have a sealing tape with no holes. The breathable end is the one with holes!
• Always use sealant on screw holes, we’ve used a specific polycarbonate sealant which is flexible and allows for expansion.

This job was really quite simple to do, given that everything arrived cut to size! I wouldn’t say it required any major DIY skills, but it’s definitely worth taking your time over and could be a bit fiddly/awkward at times. It took us a full day to complete and preferably, I recommend a nice day to do it!

If you want to see how the room looks now it’s fully complete: check out this post!

What do you think? Have you/would you ever use polycarbonate roofing? Let me know if you have any DIY fitting tips of your own to add!

Costs

(rounded to the nearest pound)

New Tools Purchased: None

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

Total: £324