# Forum Home Renovation Kitchens  installing exhaust vent through roof for rangehood

## barned01

Hoy hoy
I am trying to search for the method on how to install the piping for the exhaust vent through the roof to the outside.
it is a circular style ductwork and will be going through corrugated colourbond roofing. 
I am pretty sure i can reasonably estimate the hole in the ceiling to get into the roof cavity but how do i line up to get the hole to go through corrugated roof.
what would be the best tool to cut the roof?
also how do I seal the corrugated roof once I do somehow get the ducting through? 
cheers
Damien

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## Bedford

> I am pretty sure i can reasonably estimate the hole in the ceiling to get into the roof cavity but how do i line up to get the hole to go through corrugated roof.

   Use a plumb bob.  

> what would be the best tool to cut the roof?

   Tin snips should be fine.  

> also how do I seal the corrugated roof once I do somehow get the ducting through?

   Use one of these in a suitable size.  :Smilie:   Roof Vent Pipe Flashings, Seals and Rubber Washers | Aztec Washer Company, Inc. 1-800-WASHER 5 (927-4375)

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## SilentButDeadly

1.  Do what Bedford suggests.....or cut a hole where it is practical to mount the top hat (like against a rafter) and connect the two using semi-rigid expandable metal ducting. 
2. drill a few small holes in the tin to get a pair of aviation snips and cut in a circular fashion out to your marked line. 
3. Use a Dektite rubber flashing - available in all good hardware stores - and follow the instructions

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## Bedford

> 3. Use a Dektite rubber flashing

  Thanks SBD, for the life of me I couldn't think of that "Dektite" name last night. :Smilie:

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## NoviceReno

Hi,  
Can I jump in and ask your advice re. installing a exhaust vent for a rangehood through a tiled roof?  
The vent is square shaped 222 by 165mm.  
Main concern is how to make it water proof. What type of flashing system do I need to use?  
What would be the steps in getting the vent it?  
Thanks for the advice in advance.  
Cheers 
Seb

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## SilentButDeadly

Convert the vent outlet to round (at least 150mm diameter) and purchase the ducting, roof hat & tile flashing (essentially a malleable sheet of aluminium bitumen composite) from a plumbing supply outlet. 
If you do a google on 'rangehood ducting'......you'll find much helpful stuff.

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