When building a lean to polycarbonate roof, arguably the most important step to ensuring a long-lasting roof is how you install your roof flashing.
Polycarbonate sheets are popular with homeowners and trades as a fast way to build a clear roof without the expense of glass. Whether building a lean-to over a deck or carport, polycarbonate sheets provide end users with a durable and affordable roofing solution.
However, to ensure maximum lifespan on a polycarbonate roof, it is crucial to understand how to seal the back wall with a roof flashing. It is the last step of the installation but can be the make or break of a roof.
In times past, installers would have used flashing tape or lead roof flashing to seal the back of their roof, however, there are major disadvantages to both that called for a better solution. Flashing tape would have been considered the easiest of these options with a simple stick-on installation. Using flashing tape for a polycarbonate roof looks fine on day one but long-term isn’t durable or watertight. Naturally, the adhesive degrades over time and when installing flashing tape can be hard to adhere to all wall types properly.
Lead roof flashing is more durable however, its downfall is in the fall it is hard to correctly install and takes time to cut out, notch in, secure and seal. The end result can be a crinkly or folded-looking flashing.
What’s more, with both flashing tape and lead flashing it can be hard to fully seal around the top of your roof, over the rise and fall or the glazing bars and polycarbonate sheets. If any gaps are left it can allow moisture/rain to drip down and cause rotting or damp on the roof structure below. This could substantially affect the lifespan of a polycarbonate roof.
The introduction of the Top Wall Flashing bar eliminated all these challenges in a single solution. It is fast to install and requires only basic DIY skills. Moreover, the Top Wall Flashing is manufactured from aluminium providing a much superior lifespan and strength.
With a unique foam gasket, the Top Wall Flashing is designed to effectively seal over your roof and remove the need for complicated flashing joints or shaping. It also helps prevent any rain from seeping back up under the flashing to prevent water from reaching the roof frame.
Whether there is a big or small budget, installing the Top Wall Flashing is an obvious choice that is affordable whilst providing significant benefits. Read on to learn how to install this roof flashing onto a polycarbonate roof in 10 simple steps:
Tools required:
- Appropriate PPE
- Measuring Tape
- Pen (non permanent)
- Hacksaw or Chop saw (with metal blade)
- Cordless Drill and HSS Drill bit
- Securbond® Silicone Sealant or Flashing Tape
- Suitable Wall Fixings (select suitable stainless fixings that will work with your wall substrate)
How to install Top Wall Flashing on a Polycarbonate Roof - Steps:
1. Safety first – always wear the appropriate PPE
2. Measure the width of your roof from gable to gable and mark this length onto the top wall flashing with your pen
3.Select a Hack Saw (or Chop Saw) with a metal compatible blade and trim the roof flashing to size
4. Next, trim the foam gasket down to length with a knife or saw, to match the flashing size. The foam gasket will be supplied in lengths so you will only need to trim the last one. Slide into the gasket channel.
5. Optional – as Snapa Glazing Bars have a medium profile height (compare to the shallower Alukap options) it is sometimes suggested to mark on the foam gasket where each glazing bar meets flashing. Then cut out a small notch at each mark so that the gasket sits completely snug to the Axiome Polycarbonate sheets.
6. Predrill fixing holes into the Top Wall Flashing flashing at regular intervals along the fixing guideline. Use a drill with an HSS (or other metal-compatible) drill bit. The fixing interval spacing will depend on your wall substrate and fixing type.
7. Pull the Polycarbonate sheets protective film back to clear the foam gasket
8. Place the flashing in situ and hold it down to compress the gasket onto the sheets. Once in place, fix the flashing to the wall using stainless-steel fixings. The fixings shown are illustrative only and should be sourced according to your wall substrate.
9. Once fixed firmly, seal along the top lip with Securbond Silicone to fully seal it off. Alternatively, you can use Securbond flashing tape.
10. To complete, fully pull off the protective film on the roof sheets and glazing bars
Common Roof Flashing Questions
Does the Top Wall Flashing work with all types of Polycarbonate Sheets?
Yes, you can use this same method for installing our polycarbonate roof flashing on Axiome Multiwall Polycarbonate or Axgard Solid Glazing Sheets.
If you are looking for a corrugated wall flashing, then we manufacture a corrugated Top Wall Flashing for our Corrapol® BT Bitumen Sheets, Corrapol Clear Roofing Sheets and Corramet Sheets. It shares the same great features, with a fast installation process and a long-lasting water-tight seal.
Are there different Top Wall Flashings for different glazing bar systems?
Yes, although they share the same unique design, there are different versions of the Top Wall Flashing to suit different glazing bar systems. The 3 main wall flashing versions we manufacture are the :
• Snapa Top Wall Flashing
• Alukap-XR Top Wall Flashing
• Alukap-SS Top Wall Flashing
Why use a Top Wall Flashing for a Polycarbonate Roof?
The Top Wall Flashing has been designed to create a superior wall flashing for polycarbonate at an affordable cost level. It has an excellent lifespan and strength that is unmatched by alternatives. Here are the other top reasons why a Top Wall Flashing is required on every polycarbonate roof:
1. Improved fixing strength – its simple mechanical fixing removes the reliance on adhesive and complicated fixing methods
2. Improved aesthetics – The colour matches your roof flashing to your roof and avoids the dull grey colour. Who doesn’t want a better-looking roof?
3. Multiple angle options – The Top Wall Flashings are manufactured to be installed on a wide range of roof pitches and provide two fixing angles.
Why is it better to use top wall flashing rather than lead roof flashing?
Using a Lead Roof flashing is great if you are a qualified professional, however, it is a challenging installation process if you are less experienced or are a homeowner completing their own DIY project. Cutting lead properly into your brickwork and then securing and sealing it back is a complicated process.
Additionally, installing lead flashing is a tedious and time-consuming task. Using a Top Wall Flashing is a quick easy process that will take minutes rather than hours.
What colours is the Top Wall Flashing manufactured in?
We manufactured the aluminium Top wall flashing in brown, white and bespoke colour options. The most popular colour is white and for our Snapa PVC glazing bar range the only colour option is white to match the bar colour.
If you are installing our Alukap-XR Aluminium Glazing Bars or Alukap-SS Self Supporting Glazing Bars then there are dark brown and bespoke colour options to suit.
Why are stainless steel fixings needed for the Top Wall Flashing?
The type of fixing you use with the Top Wall Flashing is dependent on your wall substrate so always source the correct screw for your wall. However, it is important, whatever type of fixing, that it is stainless steel for maximum longevity and to avoid the fixings reacting with the aluminium flashing.
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