New Pergola idea - thoughts?

[JR86]

I'm in the planning phase with my pergola project and I've come across this design and I much prefer the look and fact that the roofing sheets aren't fixed needing a glazing bar.

I am considering building mine very similar with the 10mm polycarbonate twin wall sheets slotted straight into a 20mm routed channel into each rafter, then sealed with some flexible sealant which should allow for some movement.

My build would be free standing and not fixed to the property and pointing up the other way as i am placing it next to lean to extension and draining back into that gutter.

My questions are.....

Do you think it would leak?

How do you think the exposed but treated 6x2 rafters would hold up to the elements in the UK? (also planning on painting it as per the pictures)

What sealant would you use on the timber channel to the sheets?

Any other thoughts?

 

[freddiemercurystwin]

Homemade glazing seldom works, plenty have tried and failed. 10mm is very thin. The rafters will be ok but anything built in timber and exposed to the elements will have a limited lifespan.

 

[johnny2007]

Treated timber is fine.
Initially give it 3 coats of Sadolin classic (colour of your choice), then every 5 years or so give it a coat.
I've had mine 25 years and the wood is still solid.

 

[foxhole]

I used plastic joint strips at £10 each , makes it so much easier , no exposed timber .