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I pulled the trigger now I'm scratching my head-Grow house

Gargoyle91

Gargoyle91

I had a back deck that leads into the garage that I thought would be the perfect place for a winter greenhouse and summer shade house since I wasn't using it and junk was stacking up on it I said what the hell. Now that I have the framing built i'm kinda tossing around how i should do it. Should I cover the whole thing in plastic or should I do the bottom half in plywood and only the top half and roof in plastic. I'm sure its going to be a learning experience with temp control, The 2 windows on the inside are bedroom windows i was hoping that it would add a bit of heat in the winter and cool in the summer with the windows open.
 
How would you experienced guys do this? This is my 1st real attempt at a greenhouse just finished the framing today.
 
 
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I did almost this exact thing but up on a 2nd floor deck.
 
Greenhouses typically have a 2' kneewall. Not half. Mine didnt have one at all.
 
I went with 4 mil plastic, untreated for UV. It would last about a whole year. An actual greenhouse covering would probably look better and last a lot longer.
 
I did the same thing with leaving our door open. My climate is a lot colder though. Maybe put a fan in the window and one in the greenhouse itself.
 
Youre going to want that deck sealed over probably but conversely youll want a fan in the door on warmer days. Typically with sun it was +30 degrees in mine and barely warmer on cloudy days, which were the majority. At night I used a small space heater to keep from freezing. Not sure youll have this problem. And you probably have a lot more sunny days in winter.
 
Humidity was a problem. I hope that window AC wont be running. I guess you said both windows though. The door might be better for air exchange since it allows more space for temp differential...hot air on top, cooler on bottom.
 
Repaint those walls for better light reflectivity.
Maybe at least for the top. Especially if its a shade house come summer.
 
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Your framing looks really straight.  Better than anything I have ever built.  I would go up the sides a bit if you have dogs, kids, or are a klutz like me.  Rolled plastic sheet is really easy to fall threw.  A bit up the side also looks cool and gives you the opportunity to insulate a bit if you like.  I forget the name, but there is a type of plywood that has grooves in it.  Once painted, it looks like old world wood planks and it is really cheap.
 
I am seeing some design issues you should probably address.  The first is a biggie, I think I am seeing a flat roof area.  Even if it does not snow in your area, the weight of water on a thin plastic roof will cause it to sag between the joists, then it will puddle where it sagged.  If your roof is going to be hard plastic, you can get away with a mild slope.  If it is the thin plastic that that comes in rolls, you really need a good incline.
 
Even if you do not have nosy neighbors, I really think the flat roof is a bad idea.

Next issue is that since you are blocking an exit, you should probably install an exit.  Now we both know that in an emergency we can go right threw the plastic. But many places have building code concerning the number of doors and their locations.  If a grumpy neighbor decides to screw with you, they could call code enforcement.  Which brings me to a biggie that you can not really correct.

Building code often stipulates the use of treated lumber if you are close to the ground.  Here it is 18".  If you did not use treated lumber, consider a base cote of thinned down green paint, then a thick top coat.  The thin green paint is often enough to fake someone out if they decide to screw with you.
 

 
 
ajdrew said:
Your framing looks really straight.  Better than anything I have ever built.  I would go up the sides a bit if you have dogs, kids, or are a klutz like me.  Rolled plastic sheet is really easy to fall threw.  A bit up the side also looks cool and gives you the opportunity to insulate a bit if you like.  I forget the name, but there is a type of plywood that has grooves in it.  Once painted, it looks like old world wood planks and it is really cheap.
 
I am seeing some design issues you should probably address.  The first is a biggie, I think I am seeing a flat roof area.  Even if it does not snow in your area, the weight of water on a thin plastic roof will cause it to sag between the joists, then it will puddle where it sagged.  If your roof is going to be hard plastic, you can get away with a mild slope.  If it is the thin plastic that that comes in rolls, you really need a good incline.
 
Even if you do not have nosy neighbors, I really think the flat roof is a bad idea.

Next issue is that since you are blocking an exit, you should probably install an exit.  Now we both know that in an emergency we can go right threw the plastic. But many places have building code concerning the number of doors and their locations.  If a grumpy neighbor decides to screw with you, they could call code enforcement.  Which brings me to a biggie that you can not really correct.

Building code often stipulates the use of treated lumber if you are close to the ground.  Here it is 18".  If you did not use treated lumber, consider a base cote of thinned down green paint, then a thick top coat.  The thin green paint is often enough to fake someone out if they decide to screw with you.
 
 
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Yea I looked at the incline its a 5" slant from top edge to bottom hoping that will be good and I have already dealt with neighbors been here 15 years so we all have an understanding lol  as for the exit I did put a big door in front not sure if you can see the hinges in the pic -I do thank you for the treated wood part I'm not ever going to use that arsenic treated crap if I can get away with it but your paint idea was a good suggestion.
 
I would consider an exhaust fan near the top and venting for the summertime. Or you'll have major heat and humidity issues.
 
And the siding AJ is talking about is called T1 11, I think.
 
Gargoyle91 said:
 
Yea I looked at the incline its a 5" slant from top edge to bottom hoping that will be good and I have already dealt with neighbors been here 15 years so we all have an understanding lol  as for the exit I did put a big door in front not sure if you can see the hinges in the pic -I do thank you for the treated wood part I'm not ever going to use that arsenic treated crap if I can get away with it but your paint idea was a good suggestion.
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I agree with AJ on this. Don't use thin plastic with that flat roof or you'll end up with a giant water balloon. You might even consider the clear corrugated sheets for roofing material (http://www.intelasun.com/?gclid=CKjlvPqrpsgCFQhafgodtj8Ehw). Other than that your frame looks great.  
 
Gargoyl, at this point it wouldnt take all that much to raise the roof near the house under that overhang and make more of a grade.  I think the grade you describe might work for light rain, but snow and I really think you are screwed.  Maybe I am paranoid.  Building a high tunnel, round top, and even if I am not growing in it (ye right) I am heating it when it snows to battle accumulations.

Maybe I am paranoid about neighbors and code enforcement.  Have lived urban and got screwed a few times.  Hell, I put up a prefab plastic garden shed.  The type that snap together,no poles in the ground, no concrete slabs.  I got busted because I did not have a building permit and it was six inches too close to my house.  Now live very rural cause can not stand that bs.  That and I can not afford land in built up areas.
 
Hogleg got the name.  Now that he said it,I remember it.  I put that stuff on a fair building 8 years ago with nothing but stain (both sides).  Looks old world and stands up to the weather great.  Almost like wood paneling for the outside.  Not as cheap as OSB but that stuff is called balloon board for what happens when it gets wet.
 
ajdrew said:
Gargoyl, at this point it wouldnt take all that much to raise the roof near the house under that overhang and make more of a grade.  I think the grade you describe might work for light rain, but snow and I really think you are screwed.  Maybe I am paranoid.  Building a high tunnel, round top, and even if I am not growing in it (ye right) I am heating it when it snows to battle accumulations.

 
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He's in Long Beach Ca. Snow is not gonna happen at his location. Still I agree a rigid roofing is the way to go, with that pitch.
 
hogleg said:
 You did a great job on the framing, I'd hate to see ya scrimp on the lid. The local Home Cheapo or building supply should have this fiberglass shit for a good deal cause they buy in massive bulk.
 
example:
 
http://www.eplastics.com/Plastic/corrugated-fiberglass-panels/8oz-clear-corrugated-fiberglass-panels-2-1-2-corrugation-26-x-96
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Yea  was just trying to do this on the cheap already into it $600 materials and help , But I'm this far so I might as well do it right in the 1st place.. I'm just trying to wrap my head around how well that corrugated stuff will hold temperature. And if I remember right those clear panels at Home Depot were like $30 a pop, I'm going down there today to check them out. I think what ill do is go with this
 http://www.google.com/shopping/product/7018680987041571403?lsf=seller:8740,store:5963332734948596167&prds=oid:10116379243601803438&q=corrugated+plastic+roofing+home+depot&hl=en&ei=IR4QVr2UK4_VoATg06_IDg&lsft=prds:oid:10116379243601803438,q:Roof+Panels:+Palruf+Roofing+Supplies+26+in.+x+8+ft.+White+PVC+Roof+Panel+101336,lsfq:AA316epHwuB7VCdfvwjaSa4yGASuSx2XSmhq78CwhJxqM9eoff3u0nAAhhmrD638t3tDjNdvIq_olUW6Ljbz22noO6tzmFDyUxdOwQxuVLgOuATmmYMqImc,hl:en,ei:IR4QVr2UK4_VoATg06_IDg,cm_mmc:SEM%7CG%7CPro%7CLIA%7CD22,gclid:CN75hYb3psgCFQeUfgodgzoK9A,gclsrc:aw.ds&lsft=gclid:CN75hYb3psgCFQeUfgodgzoK9A
 
for the roof and cover the inside ceiling with plastic to maintain temp. I think I'll also build a couple of hinged panels into the walls to open for venting.
 
Hogleg,I don't think a ridge would work cause either way you put it the water will dump into the house.  But without snow, it looks like that rigid plastic you suggested would work great.  I have used the same thing for a barn.  You can get this foam stuff cut the same size as the wave.  It goes between the wood and the plastic at the end and makes for fine insulation.  They also have screws that look like the roofing nails with the plastic washer.to prevent leaks, but the plastic washer melts in the sun.  The stuff I used was not clear, same stuff but looked kind of like an old tin roof but cheap as can be.  Good stuff cause I am cheap as can be.

They have an expensive version at Lowes.  I do not know if it is any better, but its a brand name, the foam is a brand name, the screws are a brand name.  Might all be the same but by putting it together in one nice little display they can charge more.

BTW: This reminds me of hanging out at the little grocery store / restaurant on a Saturday morning.  Everyone is all the time talking about I gotta build this, I gotta build that.  Good ol boys spend more time drinking coffee and talking about doing a thing than doing it.  Its great.
 
dragonsfire said:
Framing looks great ! Is the roof totally flat, no incline?
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dragonsfire said:
Framing looks great ! Is the roof totally flat, no incline?
Click to expand...
 
 
Yea it's got a 5" incline it was the most I could do without going on top of the existing roof and covering the windows.
 
Gargoyle91 said:
I had a back deck that leads into the garage that I thought would be the perfect place for a winter greenhouse and summer shade house since I wasn't using it and junk was stacking up on it I said what the hell. Now that I have the framing built i'm kinda tossing around how i should do it. Should I cover the whole thing in plastic or should I do the bottom half in plywood and only the top half and roof in plastic. I'm sure its going to be a learning experience with temp control, The 2 windows on the inside are bedroom windows i was hoping that it would add a bit of heat in the winter and cool in the summer with the windows open.
 
How would you experienced guys do this? This is my 1st real attempt at a greenhouse just finished the framing today.
 
 
1a_zpswatgzsd5.jpg

2a_zpsydgxxljk.jpg
Click to expand...
question about you're roof, does that 2x4 going opposite of others in the middle, go all the way through or is it blocks in between? if it goes all the way through, then it would be stronger being 3-ply, staggering the joints if it isn't one single piece. then, add hangers where they hit in the middle on both sides. 
If those are blocks going through the middle, then, may want to change it altogether.
 
ChocolateScotch, if you expand the top picture it makes it look like the one two by four down the center is a bunch of blocks to keep the two by fours from flipping sideways.  Curious to know why you suggested staggering the blocks for more strength.  I certainly agree staggering the blocks adds strength, also makes it a hell of a lot easier to get the screws in.  But wondering how sound a roof that holds nothing but 4 to 8 mil plastic has to be.

Asking because I hope to get on a pit house soon.  Probably going with a roof much like that with a higher pitch.  Even if it is just carrots and lettuce, I want fresh produce in the middle of the winter without paying a heating bill.
 
ajdrew said:
ChocolateScotch, if you expand the top picture it makes it look like the one two by four down the center is a bunch of blocks to keep the two by fours from flipping sideways.  Curious to know why you suggested staggering the blocks for more strength.  I certainly agree staggering the blocks adds strength, also makes it a hell of a lot easier to get the screws in.  But wondering how sound a roof that holds nothing but 4 to 8 mil plastic has to be.

Asking because I hope to get on a pit house soon.  Probably going with a roof much like that with a higher pitch.  Even if it is just carrots and lettuce, I want fresh produce in the middle of the winter without paying a heating bill.
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I've been mulling it over while painting and cleaning the deck/walls to paint. I Really should add a couple of post and a 4x6 across as of now I wouldn't trust it to hold my 250 pound ass so I planned to roof it with a ladder but if I put the beam across should hold me easy and make roofing it a breeze. 
 
Sounds like snow is not a problem.  Mine has a 2/12 pitch and I have to scrape off the snow when it get 12 in thick just to be safe. 
 
You could put a double 2x6 in the middle under/perpendicular to the 2x4 roof joists for a beam to help with the load.  Add a double joist hanger at house wall with tapcons and a double 2x4 post in the outside wall to support the other end.  A 2x4 typically can span 8 to 10 feet.  It will span more for the roof with no snow load but it might be noisy with pressure bowing up and down.
 
If you can find twin-wall polycarbonite cheap that is the best option for your roof.  I get it at Menards for about 1 $/sf.  It is much easier to tie into/trim out than the S (wavy) panel.
 
I can gain 40-50 degrees in my 7x12 GH.  It is a shed roof built on a deck with gaps in the deck flooring.  In the winter I put a sheet of the cheap foil/foam type underlayment that is used under laminate flooring.  Then I put cheap outdoor carpet over than.  This cut out the breeze and cold air from the 1/4 gap in the deck boards.
 
HERE is going to be your issue.  The heat gain is probably going to be 40-50 deg.  Especially since your design has 2 house walls and is not freestanding.  That will put you over 100 on a typical 50-60 deg sunny day.  I would go with a hard roof such as the polycarb.  I would put 2 to 3 feet of T11 plywood on the bottom.  Next I would put screen.  Then I would put GH plastic over the screen.  In the summer you take off the plastic for a nice breeze, keep it cool and keep the bugs out.  You can cover the whole thing in plastic for this winter and do it in phases.  Get a good coat of primer and paint on the wood before you sheet.  You can also go with a light colored 7-10 year stain. 
 
I have mine set up with a cheap attic thermostat which kicks a fan on and exchanges air with the house.  It blows in hot air on during the day.  It can get to 90 deg on a 40 deg day.  At night the air from the house heats the GH to the 50s.  This extends my GH grown from March to Nov compared to May to Oct outside.
 
Here is a pic of mine in March and I already have the shade cloth up because it get too hot.  I did it on the cheap with scraps.

 
I have also built a lot of sunrooms and 3 season rooms.  Let me know if you need any help on something.
 
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