How to attach replacement poly roof sheets?

[ruz]

Hi there, I’m going to replace the clear poly roofing on my outdoor verandah with suntuf poly from Bunnings this weekend if the weather allows. 

I’m not too handy so apologies in advance. 

I have all the bits and bobs I need, but I’m not too sure where I should be screwing in the new sheets. There’s plenty of videos on installing new sheets but I can’t find anything on replacing old sheets.

The screw position required is pretty specific but as I understand it I shouldn’t be reusing the holes already there, I should be drilling fresh holes into the frame. 

Can I secure the new sheets through the existing holes on the frame or do I need to put the screws in fresh holes in the frame? 

If I can’t reuse the existing holes, can I fudge the screw position somehow?

Thanks in advance for any help 🙏

 

  

[JacobZ]

Hi @ruz,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

There's no harm in using the same holes if possible, and for aesthetic purposes, it would be better to have fewer holes.  

Unfortunately, because you have an aluminium framed pergola, there is no real way you could fill the holes and then screw back into them in the same location. If you have screws of the same diameter as the old ones, then there is a chance they would still grasp the metal if they were driven into the same hole. This would depend on how deformed the metal is when the screw is removed, so there are no guarantees.

If they are larger in diameter than the screws that were previously used, then they will almost certainly be fine to use in the same holes.

I would test to see how your screws perform in a few different holes before committing to a plan. If more than 90% are fine, I would just use the same holes.

If you are finding the screws aren't working in the existing holes, you can likely follow a similar screwing pattern relative to the old sheets, just start laying your sheets from the opposite end of the pergola. It would be pretty unlikely that the location of the screws is perfectly symmetric, so starting from the opposite end should make your sheets align differently to the existing holes allowing you to add your new screws with no worries.

The other option is to just aim the screws slightly higher or lower on the rafter than the original screws.

There are a few options, but hopefully your new screws will just drive into the old holes without any worries.

Let me know how you go and if you need any further assistance, please don't hesitate to reach out.

Jacob

[AlanM52]

I have done this before and used the same screw holes.

Go s.l.o.w and initially focus on drill torque settings, wind it right down and ratchet up while nudging the trigger until the screw is bedded down - no further. With the drill at that torque setting do a few more and you should be good to continue, if you come across stripped holes use the next size up.

Good luck