# Forum Home Renovation Pergolas, Gazebos, Strombellas & Rotundas  Pergola Correct Fall

## dub3media

Hi there I am wanting to help my dad build a pergola over his deck for the summer, There are posts going up a good 3 m up from the deck already, I think the owner before was planning on building a pergola but ran out of time, the old man wants to run rafters and have that clear lite stuff over the top so we can still sit out there when its raining. 
My questions as I am pretty new at it. 
What is the correct fall for water, the distance is about 3m from the house to the end of the deck? 
Also to fix a stringer to the house at the top above the sliding door, what is the right way to do this, eg. weatherproofing etc, its a weatherboard house? 
thanks in advance.

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## Bloss

Guidance for the fall can be obtained from the website of the polycarbonate roof manufacturers such as http://www.laserlite.com.au/PDF/Lase...te_install.pdf (I don't know NZ ones), but the usual minimum is 5 degrees (ie: 88mm per lineal metre - 264mm for your 3m). Depending on rainfall patterns etc. you can go as low as 3 degrees, but at that low a pitch a heavy downpour will see the water running deeper than the corrugations so expect some leaks. 
In Oz I would suggest you get hold of Allan Staines book Decks & Pergolas, but not sure if they are available in NZ - get it if you can as it will give you good guidance on what you need to do. In Oz it you would need approval for a pergola such as yours - worth checking where you are too. 
In any case you should get some graph paper and draw up some plans to scale so you can work out what you need to buy and angles and heights etc.  
With a weather board house you should be able to use suitable screws to affix a ledger to the wall and you will need to drill and bolt the beam on the outer edge. But sizing etc is important and to do that you need to get some advice on your specific site from someone with experience and knowledge of the local legal requirements.

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## wizard

> Guidance for the fall can be obtained from the website of the polycarbonate roof manufacturers such as http://www.laserlite.com.au/PDF/Lase...te_install.pdf (I don't know NZ ones), but the usual minimum is 5 degrees (ie: 88mm per lineal metre - 264mm for your 3m). Depending on rainfall patterns etc. you can go as low as 3 degrees, but at that low a pitch a heavy downpour will see the water running deeper than the corrugations so expect some leaks. 
> In Oz I would suggest you get hold of Allan Staines book Decks & Pergolas, but not sure if they are available in NZ - get it if you can as it will give you good guidance on what you need to do. In Oz it you would need approval for a pergola such as yours - worth checking where you are too. 
> In any case you should get some graph paper and draw up some plans to scale so you can work out what you need to buy and angles and heights etc.  
> With a weather board house you should be able to use suitable screws to affix a ledger to the wall and you will need to drill and bolt the beam on the outer edge. But sizing etc is important and to do that you need to get some advice on your specific site from someone with experience and knowledge of the local legal requirements.

  You cant get any better advice than this! Fantastic :2thumbsup:

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