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How to build flashing for pergola against two walls of the house?

kiwijunglist
Finding My Feet

How to build flashing for pergola against two walls of the house?

We are building a polycarbonate roofed pergola over a deck, see model below.

We will run spouting on the lower side and tie into the house spouting.

 

kiwijunglist_5-1717053879800.png

 

We live in a windy area.  The pergola is engineered for the wind, has 200x200 house posts (8 of them) with 2/190x45 beams and 190x45 rafters on 600 centers and will have purlins or noggins.  It's also tied into the deck.  The problem is that it's quite a long length of almost 6m and by the time you get to the far end if you have a 5 degree pitch you loose 50cm in height.  If you have a 3 degree pitch you only loose 30cm in height.  So we are thinking of using a 3 degree pitch roof using 5 rib polycarbonate which is rated for 3 degree slope.  

 

I thought I would run the top part of the roof over the top of the existing spouting or even could potentially run it a little over the roof as well.  Something like this maybe?  We do realise that it wont be completely water tight and it is an outdoor area.  But we want to minimse water coming in through the gaps.

 

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Here are some actual photos of the deck / house.  I am not sure about the interaction between the side of the pergola roof and the side of the house (spouting/fascia/eaves).  The problem is the side of the pergola roof will go from above spouting height, to alongside spouting height, to below the spouting height.  ie. there is a 30cm drop in height (3 degree pitch).  The spouting height is probably about 10cm and then there is about 7cm of fascia below the spouting.

kiwijunglist_0-1717055296089.png

 

 

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Can I please get suggestion on the top flashing and the side (barge) flashing.

kiwijunglist
Finding My Feet

Re: Flashing for pergola against two walls of the house

kiwijunglist_0-1717065050314.png

 

Re: Flashing for pergola against two walls of the house

I guess my main question is what sort of flashing could I use for the side of the roof, if I use the lower roof option?

 

kiwijunglist_0-1717065922654.png

Do I just use a barge flashing and have a gap?  or is there some other option?

 

kiwijunglist_1-1717066012100.png

 

Dave-1
Home Improvement Guru

Re: Flashing for pergola against two walls of the house

Afternoon @kiwijunglist 

The barge flashing is what Id be going with, It just needs to stop that spray of rain mist as it hits the roof. (Im not a roofer lol and I am presuming that "barge flashing" is the right angle piece of tin) I dont know if I would worry about the timber facing you have on your drawing. Unless you are going to screw through the barge flashing into it tro secure it?

 

Dave

Re: Flashing for pergola against two walls of the house

I think the side flashing is called barge flashing and it's a right angle.

 

 

I think the top flashing is called monoslope ridge flashing (based on my googling)

 

https://www.google.com/search?q=monoslope+ridge+flashing

 

I feel that the flashing would need support of a board behind it as if you are running it down into the spout i would be a large flashing

Re: Flashing for pergola against two walls of the house

Hi @kiwijunglist,

 

There are only a few styles of barge flashings designed for basic uses. In your case, due to the design, there's not really a flashing that would provide a better weather seal along the slope. Some lead flashings might be used after installation to try to cover the gaps.

 

Mitchell

 

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