greenhouse ?

[Halfathumb]

I'll be building a greenhouse for the LOML. 12'w x 8' deep. It'll be backed to the house, which means the starting height under the soffit will be 8'. My question is how much of a slope should I use for the 8' stretch out from the house to allow decent water run off?

This also brings up another thought I have. What if I try to construct some kind of system to collect the rain water as it runs off the roof? Suggestions here would also be appreciated.

Thanks,

Jim

[Arlin Eastman]

Jim

If I could suggest is going to YouTube and watching some of them.  I downloaded about 30 of them and each have a great idea that I would like to make one for us, however we want something that is 15'x45'x10' high.  Want it high so we can have a tiered system of growing and even have a tree or two growing in there.

There are a lot of videos on it showing many different ways of making one.

[R Clark]

Can't talk to the slope; I have no experience there.

Rain barrels:  That I can talk to.  I have rain barrels collecting on the house and the shop building.  It's a system that I've kluged together, and other people may have more sophisticated systems.  I use the collected water to run drip irrigation in the garden.  I really can't bring myself to pump water out of the ground so that I can put it on the ground.

To get started, you really need nothing more that a gutter downspout and a barrel.  Here's the basic configuration of my barrels:

   

As you can see, a number of my barrels are "sistered" together.  I have 600 gallons of barrel capacity at the house and shop.  I move this water to the holding tanks at the garden; I have 550 gallons of capacity in the tanks at the garden.

The collection system does not need to be complex.  But you really do need to think how you'll access that water to get it to the spot you want to use it.

Edited to add: An inch of rain on the shop building will generate about 600 gallons of water runoff. It's amazing how much water runs off of our buildings.

[Stwood_]

A 2-1/2 pitch is pretty decent slope for a 8' length of roof.
You need to figure in snow load also. No idea where yer at as far as snowfall.

[Gary G™]

Half, it depends.

My wood storage shed is about 1.5:12 with a metal roof.
It drains into the grass which runs away from the shop and down the field. No snow.

[Halfathumb]

Thanks for all of the responses. I've been and continue to search youtube for suggestions. I live in SW Mo. where snow is typically light throughout the years with very few exceptions. I live on top of a knoll and wind is prevalent more times than not. 

I'm thinking a 4 degree slope should work for me.

[Halfathumb]

Also. Since the first wall of 2x4s will butt against the house wall and under the soffit. I keep running scenarios through my head as to how to connect the 2x4 rafters at a slight angle to the wall under the soffit.

Any carpenters out there?

[Howard Pollack]

I once asked a friend, a high-end architect, about slope and water run-off.  He declined to give me a formula but pointed out that if you pour water on a flat surface like a table top it will run off of the edges...  Snow and leaves are a different issue.   -Howard

[Arlin Eastman]

Also. Since the first wall of 2x4s will butt against the house wall and under the soffit. I keep running scenarios through my head as to how to connect the 2x4 rafters at a slight angle to the wall under the soffit.

Any carpenters out there?

You can put a face or 2x4 on the rafters and then use metal clips to hang the 2x4s on.

[Halfathumb]

You can put a face or 2x4 on the rafters and then use metal clips to hang the 2x4s on.

That's where I am going. Except I don't think the metal hangers are for 2x4s and on an angle