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DIY Forum >> Building Questions >> Flashing on plastic corrugated sheet
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Message started by AndrewR on Mar 8th, 2009, 9:34am

Title: Flashing on plastic corrugated sheet
Post by AndrewR on Mar 8th, 2009, 9:34am

Can someone please advise me on the best type of flashing to use on clear plastic corrugated sheet?
I intend to cover a pergola roof that is adjecent to our house. It is built with a slight 10 degree fall away from the building so I can cover it.
I've never worked with flashing before. I'm uncertain of how easy it would be to mould the flahing to the undulations of the corrugated sheet.
Also, it seems easier and cheaper to choose the adhesive flashing strip but my house bricks are textured and so I would like some advice on whether this type of flashing forms a good bond with textured bricks?
Thank you for any advice
Andrew

Title: Re: Flashing on plastic corrugated sheet
Post by greg on Mar 8th, 2009, 9:37am

I personally do not like the self adhesive flashings and would lean towards lead

Title: Re: Flashing on plastic corrugated sheet
Post by Zambezi on Mar 8th, 2009, 11:08am

You may be able to buy pre-formed flashing that will do the job. Try and find the manufacturer of the plastic sheeting and see what accessories they offer. Something like this...
http://www.screwfix.com/search.do;jsessionid=L1BVGIA1MHQKCCSTHZOCFGA?_dyncharset=UTF-8&fh_search=65577&searchbutton.x=0&searchbutton.y=0&searchbutton=submit

I agree with Greg, the self adhesive flashing never seems to last and can be messy/difficult to fit.

Title: Re: Flashing on plastic corrugated sheet
Post by AndrewR on Mar 8th, 2009, 3:07pm

That pre-moulded flashing from Screwfix looks good, but it's quite expensive and there doesn't appear to be one for the clear corrugated sheet.
On the subject of lead flashing, is it easy to shape to fit onto the corrugated sheet?

Title: Re: Flashing on plastic corrugated sheet
Post by woodsmith on Mar 8th, 2009, 5:36pm

No, you need to dress (beat) lead into shape and I think you would struggle fitting it round plastic. I agree with Zambezi if you can get a pre moulded flashing go for that, a BnQ warehouse may have some. Otherwise I think adhesive flashing is probably the one to go for as the life of the plastic roof will not be that long anyway.

You must coat the bricks with a primer specifically designed for the flashing and be careful when you fit it, it is very thin and easy to punture

Title: Re: Flashing on plastic corrugated sheet
Post by CWatters on Mar 8th, 2009, 7:41pm

Lots of corrugated flashing on the internet but would the pitch be an exact match for what you have. I'd try the same make/source first or buy one length and offer it up. You can get it in clear. You still need some lead but only down over the upstand. Examples:

http://www.casupply.co.uk/acatalog/corrugated_fixings.html

http://www.dpcproductsdirect.com/product-detail.php?pid=24


Title: Re: Flashing on plastic corrugated sheet
Post by Zambezi on Mar 8th, 2009, 11:06pm


wrote on Mar 8th, 2009, 3:07pm:
That pre-moulded flashing from Screwfix looks good, but it's quite expensive and there doesn't appear to be one for the clear corrugated sheet.
On the subject of lead flashing, is it easy to shape to fit onto the corrugated sheet?

I was surprised at how expensive it is but it is for a particular product and you may find alternative products at much lower prices.
Lead is not easy to dress and I don't know how much of a beating your plastic sheeting will take before you damage it.
Lead and self-adhesive flashing are not clear either  ;)

Title: Re: Flashing on plastic corrugated sheet
Post by AndrewR on Mar 9th, 2009, 7:05am

Thank you for all the advice. It's interesting and helpful. I think that with this I can get the job done. If I can't get any of the pre-moulded strips with the right pitch I either use adhesive flashing or perhaps go for the more expensive polycarbonate sheet option.
Andrew

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