Help with ventilation

[Bunnybryn]

Hi everyone!

I'm a new member and need some advice on ventilation as I'm finishing my coop. I live in Central Texas and summers are HOT HOT but winters are surprising cold, windy and often wet (I grew up in Eastern Washington where we get lots of snow and often drop below freezing and Texas winters chill me to the bone!).

My coop is 4x8 and I have 7 chicks (2 are bantams). Currently I have cut out 2 windows on one side (all windows will be covered with hardware cloth) that are 3'x1'3" and one window on the other side that is 3'x1'. Additionally I am leaving the gap between the roof and the top of the walls open and securing them with hardware cloth. Is this enough ventilation? I realize how important air circulation is, especially when a good part of the year is so hot. I was considering adding additional holes at the top at the front and back of the coop, is this necessary? *The large opening on the side with the nesting box is a door*

I've attached photos of what I have so far, I appreciate any advice! Thank you!

 

[U_Stormcrow]

OK, the rule of thumb is 1 sq ft ventilation per bird. You have in excess of 9 sq ft in windows, and on;y 7 birds. So you already meet the "rule of thumb". That said, I recently left TX, and it was ^&*%(* hot. Since you are adding soffit vents under the eaves in the form of hardware cloth covered rafters, DEFINITELY install a ridge vent. Adds no time to the build, only a single item purchase (they are usually 10' long if you get metal), and it well help encourage air to flow under the roof to the peak, creating draw and helping to protect your birds from radiant heat while the sun beats down on it Jun, Jul, Aug, Sep, and into Oct.

As to cold? Its really only an issue for the babies. Adult birds with their feathers can take surprisingly cold temps without issue, so long as any feather footed ones have clean and dry footing, so they don't get caked in mud and provide a vector for frostbite.

Don't worry about a way to close off the ridge vent - you are going below freezing, but not spending lots of time below 0F.

Those things said, what are you roofing with? 5v Metal, Polycarbonate, Shingles?

 

[Bunnybryn]

OK, the rule of thumb is 1 sq ft ventilation per bird. You have in excess of 9 sq ft in windows, and on;y 7 birds. So you already meet the "rule of thumb". That said, I recently left TX, and it was ^&*%(* hot. Since you are adding soffit vents under the eaves in the form of hardware cloth covered rafters, DEFINITELY install a ridge vent. Adds no time to the build, only a single item purchase (they are usually 10' long if you get metal), and it well help encourage air to flow under the roof to the peak, creating draw and helping to protect your birds from radiant heat while the sun beats down on it Jun, Jul, Aug, Sep, and into Oct.

As to cold? Its really only an issue for the babies. Adult birds with their feathers can take surprisingly cold temps without issue, so long as any feather footed ones have clean and dry footing, so they don't get caked in mud and provide a vector for frostbite.

Don't worry about a way to close off the ridge vent - you are going below freezing, but not spending lots of time below 0F.

Those things said, what are you roofing with? 5v Metal, Polycarbonate, Shingles?

Thank you for the tips! I'm going to be putting up a metal roof.

 

[U_Stormcrow]

^^^ good choice. I suspected that was what the purlins were for. Go for "plain" galvanized metal, not one of the painted options. Maybe its not a spectacular aesthetic, it it will help with the summer heat. and even then, it will get damned hot. Don't put a bare hand on it at 2pm.

and don't forget your flashing.

 

[Bunnybryn]

Thank you for the tips! I'm going to be putting up a metal roof.

I'm new to building, it looks like the ridge vent is what goes on the very top of the roof? I bought a ridge cap but I could go buy a ridge vent as I'm guessing it would replace the cap I bought?

 

[aart]

Might want to add foam sheet insulation under the metal roofing to slow the heat gain.

 

[U_Stormcrow]

Assuming you are using the preformed metal roofing, the metal ridge cap won't sit flat on it, because the roofing material itself has a profile. The difference between the "flat" and the top of the profile on your sheet metal becomes an air gap under the ridge cap. Viola, you have a "ridge vent".

Used to be you could buy some black, roll out stuff that looked an awful lot like a 1" or 2" thick scotch bright, only about 10" wide and 20' long. Gaf "Cobra 1" - and you would unroll that at the ridge, then either cap with shingles or a metal ridge cap as normal - it would "breath" through the sides, while the woven material helped keep bugs out - but I can't find it anymore in the hardware stores, and its not worth special ordering. Extra bugs are not a problem when you have chickens.

If you do add foam sheeting, I'd attach to the underside of the rafters - even though you can't then check them for water damage easily down the road - instead of between the sheet metal and the rafters. Sheet metal expands and contracts with temp changes more than most other building materials, and requires screws with a rubber washer to seal. If you put polystyrene/EPS/XPS insulation or something directly underneath, you will need longer screws to get good holding power to the structure, and it will allow more movement overall - which will eventually wear ever larger holes in the polystyrene/EPS/XPS insulation, and increase the chances your metal screw and washer don't make a perfect seal on the roof surface, meaning leaks down the road.

 

[Bunnybryn]

Assuming you are using the preformed metal roofing, the metal ridge cap won't sit flat on it, because the roofing material itself has a profile. The difference between the "flat" and the top of the profile on your sheet metal becomes an air gap under the ridge cap. Viola, you have a "ridge vent".

Used to be you could buy some black, roll out stuff that looked an awful lot like a 1" or 2" thick scotch bright, only about 10" wide and 20' long. Gaf "Cobra 1" - and you would unroll that at the ridge, then either cap with shingles or a metal ridge cap as normal - it would "breath" through the sides, while the woven material helped keep bugs out - but I can't find it anymore in the hardware stores, and its not worth special ordering. Extra bugs are not a problem when you have chickens.

If you do add foam sheeting, I'd attach to the underside of the rafters - even though you can't then check them for water damage easily down the road - instead of between the sheet metal and the rafters. Sheet metal expands and contracts with temp changes more than most other building materials, and requires screws with a rubber washer to seal. If you put polystyrene/EPS/XPS insulation or something directly underneath, you will need longer screws to get good holding power to the structure, and it will allow more movement overall - which will eventually wear ever larger holes in the polystyrene/EPS/XPS insulation, and increase the chances your metal screw and washer don't make a perfect seal on the roof surface, meaning leaks down the road.

Yay! Thank you so much, I appreciate the help! It sounds like the cap I bought should work, and I will look into the insulation

 

[U_Stormcrow]

Happy to be of assistance, and start giving back for all the help I've received from others here.

 

[texsuze]

What type of interior wall finish will you be doing? You could add insulation (rolls, rigid board, etc) inside the coop walls if you plan to cover your 2x4 wall studs with plywood to make 'solid' walls; then paint with a light color. Even if you did just the south and/or west sides of the coop this way. One of my coops is 'double-walled' with insulation within the wall space, and it does help mitigate the heat.

Also, depending upon where your chicken run will be, and how much sun it will receive, start thinking about deep shade for part of the run, either with existing plantings (nice that you left that ashe juniper--"cedar"!), or some type of good shade cloth, louvers, etc.