Click here if you are having trouble logging into the forums
Privacy Policy |
Please read our Terms
of Service | Signup and
Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User
Bowmoreman
Carpal Tunnel
Reged: 09/11/06
Posts: 2992
Loc: Bolton, MA
|
|
Quote:
Hey yall.
Thank you very much, Rusty! Appreciate that!
Spoonsize, we usually dont get much snow. Of course, last year we got about a foot and a half. Every now and then we get that or possibly three foot if its really bad, but usually less.
You see a potential problem?
Manny, were hoping it wont be very heavy when its finished.
We hadnt thought of the roof bulging the roller 'box' thingie weve created, but I wouldnt know how possible it is to be honest. You seeing a flaw in the build that could cause that to happen?
I'd do the "cheap insurance route and have horizontal bracing (2x4 will be fine, its going to be under TENSION after all) at each/every roof joist point (either every 16" or 24", I can't remember your OC distances). This will prevent ANY bulging, and add to structural rigidity if/when you do get snow...
Any snow in Kentucky is going to be the wet/heavy type.
There is ONE downside to the bracing (but you already sorta have this anyway with the extra "triangle brace" in the middle): namely, instead of being able to have a "cathedral ceiling" you'll have a bunch of horizontal boards that will totally define your "head height" limit (when the roof is closed that is). If you're taller than the wall height, you will be constantly stooping over, etc...).
One way around this is to have that bracing be only part way "down" each side of the joist (i.e. make an "A" instead of a pure "triangle"...). That way the braces are above head height, but still add that side to side rigidity...
In my case I have the Cathedral ceiling, but my observatory is only 12 feet long... I noticed NO outward bulging even under 2+ feet of heavy Ice and Snow this last winter... the roller "box" that Scott's design creates is QUITE rigid, frankly...
Quote:
Yeah, we didnt add a cross brace, other than the pyramid thingie in the middle. Perhaps we still could?
We pretty much went with Scott's plans, changing the width and length where needed. The plans dont call for anything more than what you see.
Of course, the plans were for a 11'6"x11'6" observatory...I wonder if he does if different for bigger observatories.
First, you've done a terrific job. Second, yeah, when you increase sizing, you will sometimes need additional structural elements - in this case that bracing is cheap/easy insurance, IMO. I'd at least go the "A frame" route to keep things above head height...
Quote:
We were kinda limited in know how and ability I think.
We did the best we could with what we had.
Im hoping it will be just fine. Perhaps if it snows bad I can just keep it cleared off. 
I'd recommend a metal roof, wet snow just sliiiidddeesss right on off, and quickly melts... if you get asphalt shingles, not only will it be WAY heavier, it will have the snow STICK to your roof - a bad thing...
Quote:
I just hope it will remain stable and working.
It looks REALLY good to me overall, Michael. Great Job!
--------------------
Dave
Ustream
YLive
XT10i, RTP, CGE, R200CF, TMB80SS
31T5, 22T4, 13Ethos, 8Ethos, TV 3-6 Zoom; Paracorr
MallincamColorHyperPlus,SBIG STV&237A;CanonRebel Xti
WilderSkiesObservatory(BYO #90)
|
csa/montana
Astro Ambassador
Reged: 05/14/05
Posts: 28619
Loc: montana
|
|
Quote:
I'd recommend a metal roof, wet snow just sliiiidddeesss right on off, and quickly melts... if you get asphalt shingles, not only will it be WAY heavier, it will have the snow STICK to your roof - a bad thing...
--------------------
Carol
AstroTech 16" Dob (Thanks ASTRONOMICS!)
AstroTech 66ED / Vixen 80MF/AstroTech Voyager
Masuyama's 7.5, 15, 25W, 35mm,
Tak LE 5mm B/TMB 3.2
7mm Pentax XL, 10mm Pentax XW
14mm Meade 4000 UWA
22mm Pan, 35mm Pan
DreamCatcher Dobservatory, #2
|
Spoonsize
Vendor/Clothing
Reged: 08/27/04
Posts: 2184
|
|
Please allow me to re-iterate:
WHITE metal roofing.........
--------------------
Steve Durham
www.margesmonograms.com
(Marge made me do it)
|
WidowMaker
scholastic sledgehammer
Reged: 12/29/07
Posts: 815
Loc: Frankfort, Ky
|
|
Thank you all for the help. I was kinda sad to see that my roof could be better, but by posting pics and stuff here, Im getting free information on how to make it right! Ya cant beat that with a stick!
If i didnt say it I should have but were not finished with the roof. I was just trying to show how far we had got in one day and show our basic roof built.
Quote:
I thought Michael would use more than three trusses.
Im sorry, John. If the trusses are the three little boards with different heights in the middle of our pyramid then we did what the plans said to do.
The plans also call for running those long boards every 24" which is what weve done.
Scott's plans for the 11x6 obs has one long board down the middle and two boards on each side of it spaced 24" apart OC. We thought we were doing it right. Like I said though, I dont know if Scott does it different for bigger observatories. Were only a little over 6' longer than the plans called for.
I hope Carols' right and hell be pleased. Watch him send me a PM and say 'quit telling people I had any part in that horrible build!'
 
Quote:
I'd do the "cheap insurance route and have horizontal bracing (2x4 will be fine, its going to be under TENSION after all) at each/every roof joist point (either every 16" or 24", I can't remember your OC distances). This will prevent ANY bulging, and add to structural rigidity if/when you do get snow...
Any snow in Kentucky is going to be the wet/heavy type.
Dave, would that be what Steve drew into my picture to show me? Him drawing it into a pic like that makes it extremely easy for someone of my limited intelligence to grasp what hes saying.
Quote:
There is ONE downside to the bracing (but you already sorta have this anyway with the extra "triangle brace" in the middle): namely, instead of being able to have a "cathedral ceiling" you'll have a bunch of horizontal boards that will totally define your "head height" limit (when the roof is closed that is). If you're taller than the wall height, you will be constantly stooping over, etc...).
I think Ill be okay. We originally had a higher, more steep roof then decided a lower less steep roof might be better so we changed it last minute.
I think Ill have enough head room, and I dont mind stooping over to have my own observatory!  Small price to pay to have my own!
Quote:
One way around this is to have that bracing be only part way "down" each side of the joist (i.e. make an "A" instead of a pure "triangle"...). That way the braces are above head height, but still add that side to side rigidity...
See...im blaming it on lack of enough coffee, but im having a hard time picturing most of what yall keep saying.
I may have to wait for the wife to get home and dumb it down for me!
And to think im reading books on quantom physics and 'Death by Black Hole', but barely able to picture something im sure is so obvious to everyone else.
Did I mention I had never owned a hammer until we started building our fence? 
Quote:
First, you've done a terrific job. Second, yeah, when you increase sizing, you will sometimes need additional structural elements - in this case that bracing is cheap/easy insurance, IMO. I'd at least go the "A frame" route to keep things above head height...
Thank you very much, Dave. I just want to get it right now instead of picking it up off the lawn next winter, ya know?
We planned on bracing but all we could come up with was any metal bracing that we could manage to fit somewhere.
Having yall help me with ideas is the best help I could ask for.
Quote:
I'd recommend a metal roof, wet snow just sliiiidddeesss right on off, and quickly melts... if you get asphalt shingles, not only will it be WAY heavier, it will have the snow STICK to your roof - a bad thing...
And that brings me to the question the wife wanted me to ask lastnight before I fell asleep reading about the science you can do with just a stick in the dirt (amazing chapter!).
Can we skip the OSB roof and just do metal?
Weve got a picture I found on one of yalls pages showing a guy that has no osb, just metal roof.
That would make our roof less heavy, and still protect us from the rain and elements right?
Any downside to not having the osb?
If I knew who it was (John maybe?)I could ask for permission to post it, but hes basically skipped the osb and went right to the metal roofing.
I think he also just put metal all the way around the walls but im not so sure on that part.
What do ya think?
--------------------
Sleep is the Cousin of Death
|
Spoonsize
Vendor/Clothing
Reged: 08/27/04
Posts: 2184
|
|
"Can we skip the OSB roof and just do metal?"
Yes, but I would have framed the roof entirely differently from the start in order to do it.
I'm not sure it would be advisable to do it that way now. Let's see what the others have to say in this regard.
I can do a sketch, if you are inclined to remove the framing you have and are inclined to start over. There would not be alot different, the the differences would be considered major.
--------------------
Steve Durham
www.margesmonograms.com
(Marge made me do it)
Edited by Spoonsize (06/16/08 12:54 PM)
|
Bowmoreman
Carpal Tunnel
Reged: 09/11/06
Posts: 2992
Loc: Bolton, MA
|
|
Hi Michael... reference this crude picture... in it the Turquoise beams/trusses are what you've already made... and they are innately strong and good.
The black roof joists need to be braced - at least horizontally to make a "strong triangle" (either at the Red or at the Green location). Green is stronger, but Red is ok also... the key is to make a rigid shape.
Snow loads fat blue arrows coming down, will cause unbraced (weak) triangle roofs to want to bow outward (slightly less fat blue arrows going out either side)...
You don' HAVE to have totally vertical connectors from the peak of the roof down to each brace (like you do with your 3 "trusses"), but it would further add strength.
The horizontal braces themselves will always be under tension (i.e. the weight above them is pulling them outwards lengthwise... therefore you could even use rope or cable, doesn't have to be a board...
On the roof: you absolutely should use OSB under the metal, otherwise the roof will not be very strong/rigid since there will be large areas with NOTHING under it to support it... the alternative would be to build roof joists every 8-12", but that is MORE weight than OSB...
clear enough skies
--------------------
Dave
Ustream
YLive
XT10i, RTP, CGE, R200CF, TMB80SS
31T5, 22T4, 13Ethos, 8Ethos, TV 3-6 Zoom; Paracorr
MallincamColorHyperPlus,SBIG STV&237A;CanonRebel Xti
WilderSkiesObservatory(BYO #90)
|
John Fitzgerald
In Focus
Reged: 01/04/04
Posts: 1253
Loc: AR
|
|
I have a metal roof with no OSB. Here is a picture. I used over 400 screws with neoprene washers to fasten it down.
--------------------
?
Observing since 1966
Messier Cert #898
|
Bowmoreman
Carpal Tunnel
Reged: 09/11/06
Posts: 2992
Loc: Bolton, MA
|
|
John makes a good point... You can do it with Metal only, but then you would need Purlins (those wood pieces that run 90 degrees to your joists that can be seen in Johns picture) to attach the metal to... you would also want more bracing on each individual joist "triangle"...
Our church has spent each year for the last 5 years building 42x250' Chicken coops down in Costa Rica that are built exactly this way - we even had to hand build every truss on site and raise em up...
All things considered, and thinking again about the leak potentials, and given that Snow is NOT out of the question for you, I would amend my previous recommendation of OSB.
Instead, given your already got your joists in place, I would:
1) add the cross-member bracing; either at the higher height (making each resulting truss an "A" shape), or at the base of the truss making it a pure triangle...
2) Use 1/2" or 3/16" Exterior grade plywood (CDX) as the underlayment over the joists and under the metal...
If/when you get leaks in a metal roof; OSB turns to Mush... better to spend just a tad more on CDX rated plywood.
It's not going to add that much weight, especially since if you go Metal only, you would have to add all those Purlins to hook it to...
Now, if you want to REALLY do it right, you would put a layer of "Ice Shield" (builders commonly call it bitchathane) on top of the Plywood/OSB and under the metal...
Then you'll NEVER get a leak...
Unfortunately Iceshield is somewhat expensive (guessing that it would be at least $200 for your use).
HTH
clear enough skies
--------------------
Dave
Ustream
YLive
XT10i, RTP, CGE, R200CF, TMB80SS
31T5, 22T4, 13Ethos, 8Ethos, TV 3-6 Zoom; Paracorr
MallincamColorHyperPlus,SBIG STV&237A;CanonRebel Xti
WilderSkiesObservatory(BYO #90)
|
1965healey
Carpal Tunnel
Reged: 06/23/07
Posts: 2844
Loc: San Antonio, TX
|
|
Michael, I've been really busy of late and haven't had a chance to tell you what a great job you, and your wife, are doing building your obs. Just re-read the whole thread and have to say that you have my admiration and respect for taking on this project! You've met every challenge with humor and an unflagging enthusiasm to move ahead. For a guy with alot on his plate you sure get alot done! The obs is looking great by the way, you're really closing in on completion and then your first light! Thanks so much for sharing your journey with all of us, it's inspiring! What a great thing to be able to share this with your wife, she's a KEEPER! When it's all done you can relax in the pool (after the boys go to bed) toast each other with the beverage of your choice and smile knowing that you accomplished a project that many of us (myself included) have happily given to some one else. WELL DONE MICHAEL! I look forward to your first light report!  
--------------------
1965Healey (Karen)
Woodlawn Lake Observatory
Celestron CPC 800/FT MIcro/APT Wedge
SV NHNG 80mm #0261/CG5-GT
Celestron Omni 150 XLT
Losmandy rails/rings
Starizona CWeight system
Celestron Neximage
Sony a100 DSLR/ZigView S2
Meade DS60's w/Autostar (2)
Meade LPI/Meade DSI-C/DSI ProII
750cc Honda Shadow Spirit (Thanks Dad!)
1965 Austin Healey 3000 MKIII
|
mtber
super member
Reged: 04/05/06
Posts: 129
Loc: Apex, NC
|
|
You might also want to consider incorporating some kind of underlayment for heat management (insulation) under the metal from the outset. Three is recent thread on tekfoil for example and probably plenty of other options. It will be a lot easier to do now relative to later.
I grew up a little north of you, just across the Ohio from Louisville, and know that the heat radiating inward from metal barn/shed roofs can be brutal.
John
--------------------
12.5" Discovery Truss Dob
CGE 1100 StarBright XLT
WO ZenithStar 80 FD Anniversary Edition
Stellarvue SV66
Desert Sky Astro DSV-1 Alt/Az mount
Nikon 10x50 Action Extreme ATB
Coronado PST
SkyScout
|
mikey cee
Carpal Tunnel
Reged: 01/18/07
Posts: 2326
Loc: bellevue ne.
|
|
John....Agreed a covering of tekfoil stapled on top of the roof as each piece of metal is affixed is a darn good suggestion. I can just feel the heat in there without it!  Mike
--------------------
Mike 10x50 sears tower binocs, 3" f/10 edmunds reflector, 2.4" f/11.7 manon refractor, 6" f/8 jaegers refractor, "The 8 Ball" 8" f/13.3 brandt refractor, 3" f/15.8 sans&streiffe refractor, 3.1" f/15 selsi refractor(towa 339), 2.4" f/15 sears refractor, selsi 30x30mm spyglass, criterion 5-draw 25x45x75x spyglass(1957).
|
DeanS
professor emeritus
Reged: 07/12/05
Posts: 505
Loc: Nicholasville, Kentucky
|
|
I have some thin metal faced insulation on mine too. Even with that it becomes very warm inside. I ended up putting in an insulated drop ceiling and using a small AC unit on a timer to keep the temp down during the day.
--------------------
8" LX200gps
AP1200GTO Mach1GTO
FS-60C Tak E160 C9.25
SXV-H9 ST2000XM STV
Meade 12" Lightbridge
Moonlite Focusers
www.doghouseastronomy.com
|
Galaxyhunter
scholastic sledgehammer
Reged: 01/02/06
Posts: 894
Loc: Northern Illinois
|
|
Some form of foil insulation is a must under a steel roof. But to make the most of the insulation, you need a air gap between the foil & the steel that is vented. If you have a "Vented Air Gap", then you wont believe how good the foil works. 
--------------------
Carl
Hawkeye Observatory
Observatory - "Hawkeye"
Scope - 18"f4.5 on a GEM
8" f4.9 Orion piggy backed
Drive - Sitech Technology
DSC - Sky Commander
Planetarium - MegaStar
Camera - ST2000XM
Desire - comes & goes
Talent - ZERO, NONE, NADA (But I can Wish)
|
WidowMaker
scholastic sledgehammer
Reged: 12/29/07
Posts: 815
Loc: Frankfort, Ky
|
|
Good Mornin, Yall.
I got so caught up in school, the saw being broke at Lowe's making it impossible for me to get 4'x8' OSB roofing sheets, gray hair, ear hair, and the feeling that the lady on the Lipitor 'Do you have too much body fat...?' commercial was singling me out that I fell asleep right in the middle of 'How life Began'.
Thank you so much for the nice words and inspiration, Karen.
If it wasnt for people like yourself, Id still be on the wobbly deck hiding behind my PVC/tarp light panels!
I got 4 more 2x6x12's to make us more cross braces (the bottoms of the pyramids) and we bought every kind of metal brace we could find to help anywhere one could go.
Were going to try and brace it everywhere we can tonight (i hope).
As fas as insulation stuff, I saw the TekFoil thread and that stuff looks cool, but my local outlet carries this stuff called 'Reflectix' and says it dang near does the same thing as the tekFoil.
Anyone see a problem with that stuff?
And if its tekFoil or Reflectix, I want to put my osb roofing wood up, the insulation over that, then the metal roofing over that, right?
Dean, I noticed you had something on your ceiling like insulation, is that tekfoil? Whatever you did, it was so cold in there, I couldnt wait to get back outside to 90° weather!
That air conditioner works very well!
--------------------
Sleep is the Cousin of Death
|
Spoonsize
Vendor/Clothing
Reged: 08/27/04
Posts: 2184
|
|
"And if its tekFoil or Reflectix, I want to put my osb roofing wood up, the insulation over that, then the metal roofing over that, right?"
I would put the OSB up, then the metal roofing, then I would staple the reflectix to the bottom of the roof joists on the inside. Others may have better ideas??? What say ya's???
--------------------
Steve Durham
www.margesmonograms.com
(Marge made me do it)
|
Galaxyhunter
scholastic sledgehammer
Reged: 01/02/06
Posts: 894
Loc: Northern Illinois
|
|
Quote:
I would put the OSB up, then the metal roofing, then I would staple the reflectix to the bottom of the roof joists on the inside.
Thats the way to do it.
--------------------
Carl
Hawkeye Observatory
Observatory - "Hawkeye"
Scope - 18"f4.5 on a GEM
8" f4.9 Orion piggy backed
Drive - Sitech Technology
DSC - Sky Commander
Planetarium - MegaStar
Camera - ST2000XM
Desire - comes & goes
Talent - ZERO, NONE, NADA (But I can Wish)
|
WidowMaker
scholastic sledgehammer
Reged: 12/29/07
Posts: 815
Loc: Frankfort, Ky
|
|
Thanks yall.
lemme ask this: What about that roof paper?
The black paper stuff. In my plans it calls for that, but no one here has mentioned it.
Do yall not use it? Should I go ahead and put that up between the osb and the metal roof, then put the Reflectix stuff up on the inside rafters?
What purpose does the black roof paper serve?
--------------------
Sleep is the Cousin of Death
|
1965healey
Carpal Tunnel
Reged: 06/23/07
Posts: 2844
Loc: San Antonio, TX
|
|
In a word yes to the paper, yes put it between the OSB and the metal roofing and yes put the Reflectix stuff inside. The roofing paper helps to prevent any moisture coming in contact with your roof deck (OSB) in your case. 
--------------------
1965Healey (Karen)
Woodlawn Lake Observatory
Celestron CPC 800/FT MIcro/APT Wedge
SV NHNG 80mm #0261/CG5-GT
Celestron Omni 150 XLT
Losmandy rails/rings
Starizona CWeight system
Celestron Neximage
Sony a100 DSLR/ZigView S2
Meade DS60's w/Autostar (2)
Meade LPI/Meade DSI-C/DSI ProII
750cc Honda Shadow Spirit (Thanks Dad!)
1965 Austin Healey 3000 MKIII
|
blatterjr
sage
Reged: 08/13/07
Posts: 263
Loc: Saint Petersburg Florida
|
|
If you use wood deck, use 15# felt. As cool air (shaded inside) hits your warm metal panels (solar) you will get condensation. If you don't have a wood deck, it will drip inside or run along the panel to the eave edge. If you *do* have a wood deck this moisture will saturate the wood and begin deterioration.
Its inexpensive and easy to lay down quickly.
This effect will differ based on your climate and latitude.
Edited by blatterjr (06/17/08 01:57 PM)
|
Bowmoreman
Carpal Tunnel
Reged: 09/11/06
Posts: 2992
Loc: Bolton, MA
|
|
Cool air NEVER rises; warm/hot air does... and so whatever air that is rising inside the observatory, will ultimately hit something (whatever layer that is) above it that is warmer than it is, so no real chance for condensation from THAT effect.
The felt belongs above the OSB layer, and below the Metal Roofing...
If you then also use any reflective layer... it belongs BELOW the roof joists, so that it reflects heat UPWARDS (away from the Obs) - i.e. "shiny side" UP...
condensation will only really ever become an issue if you had built the Observatory with a (fairly) complete vapor barrier. Most observatories are (purposely) not air tight, and so condensation should (in most locales) not be an issue.
Clear enough skies
--------------------
Dave
Ustream
YLive
XT10i, RTP, CGE, R200CF, TMB80SS
31T5, 22T4, 13Ethos, 8Ethos, TV 3-6 Zoom; Paracorr
MallincamColorHyperPlus,SBIG STV&237A;CanonRebel Xti
WilderSkiesObservatory(BYO #90)
|
|
3 registered and 3 anonymous users are browsing this forum.
Moderator: Chris Schroeder, csa/montana
Print Thread
|
Forum Permissions
You cannot start new topics
You cannot reply to topics
HTML is disabled
UBBCode is enabled
|
Thread views: 15179
|
|
|
|
|
|
|
Previous
Index
Next
Threaded
[Re: 
Edit
Reply
Quote
