Coop Foundation and Predator Wire

[YaYasDottes]

I am about to start building a coop for 14 chicks. I have a teeny tiny yard, so I was hoping to elevate the coop about 2 feet to maximize the run underneath. I am also attaching to the coop an 8x10 enclosed run.

Is an 8x8 coop too big to be raised off the ground? I plan to use 2x6 treated lumber to form a frame around nine 22" high posts (3 posts per side and one in the center). Treated 2x4s will frame the upper edge of the posts. Eight-foot floor joists will be installed 16" on center between the 2x4s to support 3/4" plywood flooring. The posts will sit on 12x12 concrete patio blocks. There will be two small doors to allow access to the underside of the coop.

Should the ground under the house be lined with 1/4" hardware cloth to keep out predators? I do plan to lay a 2' wide strip of hardware cloth outside the perimeter.

I would like any suggestions you may have. I don't want to make mistakes that I must tear apart later. Your wisdom and experience would be appreciated!

 

[Mtnboomer]

Your coop and run meet the minimum recommended space requirements. Bigger is always better especially for future flock expansion...just a consideration.
Generally speaking, the maximum span of lumber is its numerical size. Example: 2x6 can span 6ft max. So long as no span is greater than 6ft it will be fine. I also have an elevated coop (32"). I used 2x8s with only 4 posts for middle 4x8 area. 2ft extend past posts on 2 sides. I enter the coop once a month for maintenance and wanted to be sure it was stable and secure.

Be sure to use only fasteners rated for exterior use. Otherwise the pt lumber and elements will cause them to corrode and fail.

HC around perimeter should be sufficient to keep out diggers without needing additional HC to line run floor.

 

[U_Stormcrow]

No, an 8x8 coop is not too big to raise - mine is approx 8x12 (not counting the attached platform for a 275gal water tote) and is 36" off the ground, with wire all around the bottom to provide a protected run inside their larger run (I have ducks who prefer to sleep on the ground, under the hen house, so it was the structure be built with them in mind).

On one side, its supported on a 2x6 legder board screwed to the side of my barn (exterior #10 3 1/2" deck screws). 2x6 PT lumber with joist hangers and galvanized #10 rafter nails carry the load to the PT 4x4 verticals in the "front". Those are spaced approx 4' apart, and secured with 3 1/2" #10 exterior screws. The raised floor (and walls) are hardie board, while the joists under the floor are just 3' 9" long PT 2x4s, end screwed on roughly 2' centers. Its enough that I can walk on it, though if I were building for human habitation I'd consider it inadequate. Has as much "bounce" as the floor of those cheaply built overpriced sheds you see on the side of the road, as their construction is similar.

Raised the thing alone - though I won't pretend I would have been able to do so had I not used a ledger board on the long edge.

 

[YaYasDottes]

Your coop and run meet the minimum recommended space requirements. Bigger is always better especially for future flock expansion...just a consideration.
Generally speaking, the maximum span of lumber is its numerical size. Example: 2x6 can span 6ft max. So long as no span is greater than 6ft it will be fine. I also have an elevated coop (32"). I used 2x8s with only 4 posts for middle 4x8 area. 2ft extend past posts on 2 sides. I enter the coop once a month for maintenance and wanted to be sure it was stable and secure.

Be sure to use only fasteners rated for exterior use. Otherwise the pt lumber and elements will cause them to corrode and fail.

HC around perimeter should be sufficient to keep out diggers without needing additional HC to line run floor.

To clarify, does this mean I need 2x8 lumber for my floor joists? Or my perimeter frame? Or both joists and frame?

 

[U_Stormcrow]

To clarify, does this mean I need 2x8 lumber for my floor joists? Or my perimeter frame? Or both joists and frame?

What are your loads? How much deflection are you willing to allow? How many joists do you plan between them? All those things are considerations - but no, on an 8' corner supported span, unless you have some crazy load considerations besides the birds, or plan to almost entirely skip floor joists, you don't need 2x8s.

 

[Mtnboomer]

To clarify, does this mean I need 2x8 lumber for my floor joists? Or my perimeter frame? Or both joists and frame?

Wouldn't hurt, other than your wallet, but its just a chicken coop. Meaning that unless you are doing something elaborate, 4 walls and a roof will be supported fine. You may see some deflection or sagging years from now but not enough to be overly concerned about.
The weight of the coop, max weight of the soiled litter, birds, feed, water, you during maintenance if you need to enter, snow, wind etc all are load constraints that should be considered although many do not. You can find some table calculators online to help determine dead and live loads of structures and appropriate building materials.

We get avg snow falls here but we get at least 1 or 2 that exceeds 10" and have gotten over 16" in recent memory. Snow load can be a major concern worth beefing up a design for. My friend in MD, in 2012 i think got 5ft of snow in a week. His barn that stood for 60yrs collapsed under the weight. Not saying you need to design for the extremes, but often its not that big of a change for small structures so why not.

Personally, I have built tree stands for hunting 25' off the ground with nothing but 2x4s back in the day. Of course i was young, dumb, and they never spanned more than about 2-3ft

Also consider "post and beam" construction. There are various design configurations that can allow you to reduce spans or size of materials but keep your coop size and retain excellent structural integrity. Example: (4) 4x4 posts set in 2 rows 8ft long 4ft apart. Laminated (2) 2x6s for beams ontop of posts with 2x6 joists centered perpendicular ontop of beams. Greatest span by floor joists would only be 4ft in middle. Just an example. Your coop may have different constraints.

 

[U_Stormcrow]

You may find this useful - Span Table from Southern Pine

and I'd be stunned if you need anything bigger than 2x6 framing with a handful of 2x4 joists whether you use 4x4 posts or California corners, your floor isn't supporting your snow load, so even that's not a consideration. (If you do have snow loads, particularly if you have a shallow roof, DO NOT cut corners on your rafters!). If you choose to 4x4 the corners, and can get away with it, placing a short 4x4 in the center under the middle of the floor cuts your spans, effectively, from 8' to 4' - probably cheaper than using larger lumber throughout, and makes the whole project just a tiny bit more managable.

If you aren't familiar, the deflection limit (L/360) is the amount of sag you can expect expressed as length over 360 - an 8 foot span is 96". 96"/360 = about 1/4" with a 40 pound "live" load applied and 10 pounds of dead load per square foot. I assume you can live with that?

I chose Southern Pine's tables, though they are standard throughout the industry, because in all likelihood, your big box store will carry either #1 or #2 grade southern pine lumber. Do not use "white wood" - its pretty, its straight,its cheap, and its entirely unsuited to spaces that may get wet.

 

[YaYasDottes]

To clarify, does this mean I need 2x8 lumber for my floor joists? Or my perimeter frame? Or both joists and frame?

Thanks for the tips, particularly pertaining to hardware cloth.

What are your loads? How much deflection are you willing to allow? How many joists do you plan between them? All those things are considerations - but no, on an 8' corner supported span, unless you have some crazy load considerations besides the birds, or plan to almost entirely skip floor joists, you don't need 2x8s.

We get very little snow here, so I'm not too worried about the load on the roof. And I would agree that 2x8 floor joists on 16 inch centers would be overkill just to hold up the floor for about a hundred pounds of chickens. I don't weigh much more than the chickens and their deep litter, so even if I put on a tap dance number for the ladies while spring cleaning, I doubt that this coop will collapse.

 

[YaYasDottes]

You may find this useful - Span Table from Southern Pine

and I'd be stunned if you need anything bigger than 2x6 framing with a handful of 2x4 joists whether you use 4x4 posts or California corners, your floor isn't supporting your snow load, so even that's not a consideration. (If you do have snow loads, particularly if you have a shallow roof, DO NOT cut corners on your rafters!). If you choose to 4x4 the corners, and can get away with it, placing a short 4x4 in the center under the middle of the floor cuts your spans, effectively, from 8' to 4' - probably cheaper than using larger lumber throughout, and makes the whole project just a tiny bit more managable.

If you aren't familiar, the deflection limit (L/360) is the amount of sag you can expect expressed as length over 360 - an 8 foot span is 96". 96"/360 = about 1/4" with a 40 pound "live" load applied and 10 pounds of dead load per square foot. I assume you can live with that?

I chose Southern Pine's tables, though they are standard throughout the industry, because in all likelihood, your big box store will carry either #1 or #2 grade southern pine lumber. Do not use "white wood" - its pretty, its straight,its cheap, and its entirely unsuited to spaces that may get wet.