Tom's Barn

Corrugated Metal Roof - how did you ventilate your panels

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Posted (edited)

Hi All

 

I am in the process of specifying the details for our new corrugated roof (dictated by the conservation officer). The main issue I am coming across is how to ventilate the roof panels because the foam closure strips have no ventilation holes in them. One supplier has sent me a foam closure for the panels which has holes drilled in it and mesh infils. This seems like a great solution but it is 20mm higher than the normal strips. Before I fully commit to this product (the only one I have seen so far), how did you ventilate your corrugated roof?

 

Many thanks for sharing your experience with this matter

 

Tom

Edited by Tom's Barn

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I am using eternit profile 6 sheeting. Rather than foam strips, I have eternit eaves closure pieces which will prevent wind driven rain,  but allow ventilation as they overhang the sarking slightly (not that easy to explain).

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HI Jamie

 

sorry I should have put the word metal in my title; just added. However, I will look at those to see if suitable.

 

Many thanks

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I have a building that faces south west and into most of the incoming storms, I  left my tin open at the bottom and open at the top, I then put a vented ridge on and used the foam closures between the tin and where the ridge flashing met the tin to stop rain driving up under the flashing and onto the roof membrane. Air is free to travel up the roof  below the tin and out the ride at either end, also I did not seal the joints of the ridge flashings as they have a good overlap and this will allow some further ventilation. Then just for good measure I left a vented gap below the timber sarking / sheeting and vented this out the gables. It’s a glorified shed so probably well over the top but living in an extremely wet environment I wanted to go overboard on ventilation.

 

I have a tin roof on another house but this faces East with the gables facing north to south and never gets driving rain from anywhere but the gable ends so I did not use any closure strips and it works great. 

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I've steel as with @Cpd and have the foam closures at the top between the corrugated and the ridge cap.

 

The bottom is left open to allow for ventilation, and I should note that they descend into a hidden gutter, so wind can't get driven up.

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Ventilation is good but wouldn't critters getting under the tin and nesting in the membrane, etc, be less good?

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Nothing in there for mice to be interested in, if anything the foam closures would be there “go to” on the menu. Spiders and a few other bugs might make a home In there but that’s not a concern to me as they won’t do any damage. My reasoning  is that I wanted as much ventilation as possible to prevent possible condensation build up and if and when there was any condensation it would dry out as quickly as possible. 

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13 hours ago, Cpd said:

Nothing in there for mice to be interested in, if anything the foam closures would be there “go to” on the menu. Spiders and a few other bugs might make a home In there but that’s not a concern to me as they won’t do any damage. My reasoning  is that I wanted as much ventilation as possible to prevent possible condensation build up and if and when there was any condensation it would dry out as quickly as possible. 

thanks for all the replies so far. With the open venting option and your push for maximum airflow I presume your tin has a batten and counter batten underneath? I am surprise to hear it has been left open. I would have thought the wasps would have loved the space under the roof. Mind you it may get a little too hot for them...

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We've battented and counter battented with standard treated battens, 38 by 25mm.

 

I guess you could place instect or rodent mesh along with the first line of counter battens to your structure, with your foam filler stapled against the counter batten and topped with mastic tape, ready for when you install the corrugated on top...

 

It'd probably be only a little bit of extra effort, but I can imagine installing the sheets on top of that will get quite faffy.

 

Win and rain has been the main concern for us, the insect and rodent issue hasn't been. Our roofers, architect and building control haven't said a thing about it either

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I start our roofing tommorow. We have mesh to install as per @Visti describes, although I have no eaves foam fillers, just a closure piece to allow a ventilation gap.

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3 hours ago, jamieled said:

I start our roofing tommorow. We have mesh to install as per @Visti describes, although I have no eaves foam fillers, just a closure piece to allow a ventilation gap.

good luck with the roof @jamieled. If you can take a picture of your install that would really helpful to fully understand your approach. Many thanks

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My roof design is different as it’s vented on both sides of the sarking. I just put the tin directly onto the sarking board. battens and counter battens are the way to go though. My roof is on a glorified shed so not trying to meet any specific standard, more aiming to prevent water getting in and if any condensation does get in then making sure it is well vented.  It’s blowing a gale outside right now with the water blowing up the 45 degree roof..... if the closer strips were not in place between the ridge flashing and the tin then the water would blow right up under the ridge flashing and onto the roof membrane and then have to travel all the way down the roof under the tin  and out into the gutters !!!!! The closures at the top are essential to prevent this. The bottom of the tin is within the gutter so rain can not get in  and wind is minimal but load if ventilation as no closer strips. 

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14 hours ago, jamieled said:

I start our roofing tommorow.

Best of luck. 

 

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