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How to fix holes in polycarbonate roof sheets?

Finding My Feet

How to fix holes in polycarbonate roof sheets?

I'm hoping you get some help with holes appearing on the top side of my polycarbonate alfresco roof. Not from hail. I've tried to get a replacement under warranty without any success (installed 5 yes ago, warranty is 10yrs, very bad), and I'm want to slow down/stop the holes forming. 


The holes are forming on the top side (not underside yet). I have covered some holes with Silicon and small square of perspex plastic. 


Now, I'm seeing (a lot) more. I suspect it is damage from UV. The roof is still keeping the rain out and the frame is still solid. I dont want to replace the polycarbonate sheets as things are working fine (keeping rain out)


I have come up with 2 ideas and i was hoping to get anyones feedback:

- paint the top part with deluxe weather shield paint OR

- tape the entire thing with Ametalin insulation tape (sarking tape), UV resistant, handles temps up to 140C, aluminium.


I don't mind blocking the sun out under the alfresco. 


I prefer the later because theres less mess and its something I can safely DIY.


Any help would be appreciated! 







Bunnings Team Member
Bunnings Team Member

Re: polycarbonate holes - how to manage?

Welcome to the Bunnings Workshop community @iflyin. It's amazing to have you join us, and many thanks for your question about repairing roofing.


Given the size of the holes, simply painting over them won't be effective, but it could provide a layer of protection, minimising further exposure to the plastic. You will need to patch any of the existing holes before painting. Please note that due to the high temperatures and expansion and contraction of the sheeting, an exterior paint would most likely not be able to cope with these conditions. There is a chance it will delaminate as it can't sufficiently bond with the polycarbonate.


Taping the whole roof could be a solution, but keep in mind that if the panels are degrading due to UV exposure, they might be very brittle and could break easily. If the panels are already showing significant signs of degradation, applying tape could cause further damage. Considering this, the best long-term solution might be replacing the sheets with something more durable, like the Suntuf range, designed to withstand UV exposure and provide long-lasting protection. 


Although it involves more upfront effort and cost, replacing the sheets will ensure the roof remains effective and reduces the risk of further issues down the line.

Let me mention a few of our helpful members, @Nailbag, @Dave-1  and @DIYGnome, to see if they have any thoughts.

Please let me know if you have any questions.


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Home Improvement Guru

Re: Holes appearing top side polycarbonate roof sheets - Help!

Good Morning @iflyin 

What a pain 😕 Looking through your photos at the moisture and that hole makes me think of hail damage, enough to either crack or put a few holes in the surface. Especially if it was super cold and a storm rolled through. I would suggest to replace the panels as being the easiest and probarly the most cost effective way to deal with the issue. Maybe wait awhile as long as it dosnt drip and save for the panels is probarly what I would do.


I do like your little "patches" brilliant idea, only problem is they can be seen :smile: But still its a good answer. I would actually continue with that type of repair but I would use something bright instead. Suntuf 900 x 600 x 3mm Red Acrylic Sheet and cut those small squares you are using. Only problem I can see is putting the squares over the hard to reach areas :smile: Broomstick with a bit of looped sticky tape? At the very least you could extend ithe life of the roof until you decide on how to move forward.


Id like to say Howdy and welcome to the Bunnings community :smile: Its a pretty friendly place with a whole range of ideas on issues. Take a wander through the pages and you will go down a rabbit hole of things you can do :smile:


One question I have, and its just a survey question type deal. Is underneath the polycarbonate hot? as in when you are outside does it feel hot hanging in the area?



Finding My Feet

Re: Holes appearing top side polycarbonate roof sheets - Help!

Thanks for the input, what a great community here! Here's a quick update what I did yday (pic below):

- cut some left-over Ametalin Foil UV-resistant acrylic duct tape into small squares and stuck them on.

- The sheets weren't brittle when i stepped on them (thankfully)


I've used this product before to tape a crack in small shed window. It is also N facing and after 3 years, it hasnt deteriorated, so i thought this would be a good temporary option.


My gut feeling is that it's not hail causing these holes because the "darker" polycarbonate sheets are unaffected, but I could be totally wrong.


I spoke to technical support at Ametalin who make the tape. I mentioned I want to use the tape to tape the entire polycarbonate roof area. It's not intended to be used in direct sunlight all year 'round, but in theory it should work because the aluminium is naturally UV resistant. I dont mind completely blocking out the sun in this area.


@Dave-1 Yes it gets hot in the alfresco in summer, but in winter it's quite nice.  


@MitchellMc Thank you! That rules our painting, I needed confirmation here, really appreciate it!


I've updated 2 options moving forward until I decide replacing, any input would be great:

OPTION 1: Tape entire affected polycarbonate sheets with Ametalin Foil Duct Tape

OPTION 2: Tape down leftover Sarking Foil, with reflective side up




Home Improvement Guru

Re: Holes appearing top side polycarbonate roof sheets - Help!

Aftermnoon @iflyin 

Thats a LOT of tape.... $$$? Unless you have access to some :smile:

The sarking being tapped down I am not a fan of either 😕


As its still waterproof I would go with how you have been handling it so far until you decide.



Ametalin 72mm x 50m Reinforced Insulation / Ducting Tape at $31.19  (for 50m so maybe 3 rolls worth all up?)

Sunlite10 Twinwall x 2.4m Clear Polycarbonate Roofing $114.50 for 2.4m * 5 of


I do see your quandry 😕 The condensation really shows up and the only way I can think of removing itwould mean taking the flashing off and that would mean you are half way towards switching out the sheets. Cost wise maybe replace a few at a time as you can afford it?





Making a Splash

Re: How to fix holes in polycarbonate roof sheets?

Hello @iflyin 🖐

That must be quite disappointing having the sheeting break down so quickly, I can attest to the quality/durability of the Bunnings SunTuf polycarbonate corrugated sheeting as it adorns a section of our outdoor cat-run which has no signs of degradation after 10 years of brutal Wimmera/Mallee Summers, any type of tape, film OR adhesive solution is only prolonging the inevitable replacement of those sheets, that said have you considered a clear paint or rolls of contact (as used to protect schools books)?  

Bunnings Team Member
Bunnings Team Member

Re: Holes appearing top side polycarbonate roof sheets - Help!

Hello @iflyin 


It's great that you've received excellent advice from our members. If you are not yet ready to replace the polycarbonate sheets, I suggest going for option 2 and just using your sarking foil on the damaged spots only. I propose replacing one panel at a time as your budget permits.


If you need further assistance, please let us know.




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Becoming a Leader

Re: How to fix holes in polycarbonate roof sheets?

Hi @iflyin Though I can't off an explanation for the small holes other than what others have suggested thinking hail damage, my experience with this product hasn't been a durable one of any scale similar to yourself. The suggested patching suggestions though will provide a waterproof and cost effective solution, I'm in the same came as @MitchellMc and would be replacing it all with a Suntuff product. The job will be simpler, cost effective and the most durable and visually appealing long term. If total costings is a concern, then as @Dave-1 suggested, maybe just a few sheets at a time.


Regards, Nailbag.

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