Quick question on measuring roof ventilation

[NorthwoodsChick]

A tired topic for sure. I know I need 1sf per bird. To max out I need 20 sf.
Hugs is roughing in a 8x10 coop having 14” overhangs on long wall remaining open for ventilation. 2x6 Trusses are 16 inches apart? How do I measure the sf in that particular space?
I have full length 4 inch ridge vent and have an option to leave gable end open on the south side only.
North side overhand is too short ().
Thx- not a builder or math major

 

[aart]

How do I measure the sf in that particular space?

Measure the distance between underside of roof sheathing and the top of the wall, then the space between the rafters, multiply those numbers to find the area of the openings..... multiply by number of those openings for total sqft. Can find calculators online to convert square inches to square feet.

 

[NorthwoodsChick]

Measure the distance between underside of roof sheathing and the top of the wall, then the space between the rafters, multiply those numbers to find the area of the openings..... multiply by number of those openings for total sqft. Can find calculators online to convert square inches to square feet.

Perfect!! Thx @aart

 

[HowIsItDone]

Measure the distance between underside of roof sheathing and the top of the wall, then the space between the rafters, multiply those numbers to find the area of the openings..... multiply by number of those openings for total sqft. Can find calculators online to convert square inches to square feet.

"to find the area of the openings..... multiply by number of those openings for total sqft."

Um, what?
Aart, can you please say that again in 'Total Newbie', so I can understand?


Our 12 x 10 coop is under construction right now.
The foundation and floor have been built, as well as one wall.

The walls will be 8 feet high, and the roof will peak at 10', across the 12' width.
We are in south eastern Ontario, Canada.
Extremes are summer at 95f to winter at -15f.
There will be two 24" x 36" windows, (E and S) and their pop door leading to the run will be on the third side (W). There will be no window on the north side, where their roost and poop board will be placed.


I know I need open vents at the top, protected with hardware cloth, but how many? Is it best to have more narrow horizontal ones, closer to the top of the coop-roof line, or larger square ones further down?
Do I use 1/4", or will 1/2" be okay?
(We used 1/4" for the floor.)


I'll be starting with 6 chickens, but may go up to 20 at some point.
Do I ventilate on a per chicken basis, adding more as the flock grows, or should I ventilate for 20 right away?


NorthwoodsChick, thank you for bringing up this "tired old topic".

Please pardon what must seem like silly questions.
I welcome any input.
This site is great!

 

[aart]

"to find the area of the openings..... multiply by number of those openings for total sqft."

Um, what?

Multiply the width and height of the openings to get the area.
Basic geometry and fairly simple math.
Not sure I can make it clearer than I did above for @NorthwoodsChick

I know I need open vents at the top, protected with hardware cloth, but how many?

The best place to ventilate in cold climates is to have large(18-24") roof overhangs with open soffits....like @NorthwoodsChick has.
Fly rafters to extend roof on gable ends to protect gable vents is good too.
Top hinged windows for light in winter and more ventilation in summer.

 

[HowIsItDone]

Multiply the width and height of the openings to get the area.
Basic geometry and fairly simple math.
Not sure I can make it clearer than I did above for @NorthwoodsChick


The best place to ventilate in cold climates is to have large(18-24") roof overhangs with open soffits....like @NorthwoodsChick has.
Fly rafters to extend roof on gable ends to protect gable vents is good too.
Top hinged windows for light in winter and more ventilation in summer.

"the openings". That's the part I don't understand.
Which openings?
The square footage of space above the walls?

I'm not the one building it, and the relative who is doing it hasn't done chicken research, he's just doing me a favor. It means I have to explain things to him.

Like yesterday when I told him we had to have 1/4 hardware cloth under the floor. He thought that rats couldn't eat through plywood.

I do get what you mean about @NorthwoodsChick's open soffits. That helped! Thanks.

 

[aart]

"the openings". That's the part I don't understand.
Which openings?

Any opening that allows air to flow thru it.
Just the standard gaps between rafters and the window openings.
Do you have a coop plan thread...showing your plans sketched out?
Might be a good idea.

 

[StinkyAcres]

"the openings". That's the part I don't understand.
Which openings?
The square footage of space above the walls?

I'm not the one building it, and the relative who is doing it hasn't done chicken research, he's just doing me a favor. It means I have to explain things to him.

Like yesterday when I told him we had to have 1/4 hardware cloth under the floor. He thought that rats couldn't eat through plywood.

I do get what you mean about @NorthwoodsChick's open soffits. That helped! Thanks.

You need to make sure the person building the coop leaves the gaps between the rafters open unlike what you would normally do for a house or shed.

Multiple the width (W) and the height (H) to get the area of the ventilation openings. I believe mine (shown here) are about 6 inches (0.5 feet) high and 14.5 inches (1.2 feet) wide. There are six openings in the front soffits which provides a little over 3.5 square feet of ventilation.

1/4-inch hardware cloth is not as strong as 1/2-inch. I'd stick with the 1/2".

 

[HowIsItDone]

Any opening that allows air to flow thru it.
Just the standard gaps between rafters and the window openings.
Do you have a coop plan thread...showing your plans sketched out?
Might be a good idea.

I asked foundation questions on this thread, but I haven't posted my plans. I should do that.
https://www.backyardchickens.com/threads/coop-foundation-challenges.1624020/

 

[HowIsItDone]

You need to make sure the person building the coop leaves the gaps between the rafters open unlike what you would normally do for a house or shed.

View attachment 3843119

Multiple the width (W) and the height (H) to get the area of the ventilation openings. I believe mine (shown here) are about 6 inches (0.5 feet) high and 14.5 inches (1.2 feet) wide. There are six openings in the front soffits which provides a little over 3.5 square feet of ventilation.

1/4-inch hardware cloth is not as strong as 1/2-inch. I'd stick with the 1/2".

Oh, thank you! I understand now!