JinMTVT
Registered Users
Posts:12
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| 04/22/2008 10:50 PM |
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| hi all! nice section of this forum :)
I am planning my soon to start project
and i am up to deciding on floors and roof
i will have a flat roof ( 50' by 30-40' )
on wich we will walk and have some kind of sun deck ... later a spa and some decoration
( spa will be on massive concrete columns :p )
the outline of the house will be in ICF
( 8" basement. 8" 1st and probably 6" second floor)
the floors should be commercial metal joists
with a metal sheet composite deck
( concrete poured over metal sheets )
some of the joists will span 40'
so i am still working on getting this together
i was going to do the roof in the same manner,
but why bother with some un necessary weight and concrete on the top + the cost
so the roof will prbably be still steel joists
@ something liek 4'c-to-c
and i was thinking of using directly some SIP
pannels on top to make the isolation and the walking surface at the same time
what do you think ?
possible ?
i was told that SIPs can span 10-15' without problems..so i believe that 4' shall not be a big problem ?
will it be safe to walk on ?
any problems i have not think of ?
how to fasten them to the steel joists underneath?
then what would you guys do for finish and weather proofing ?
i am up north in Quebec , we get a lot of snow
strong enough to support 4-5ft of snow?
i was thinking about a 2 piece EPDM membrane to cover this all and make it water proof
then i'll have to work on getting the water off the roof..any idea?
how to finish the top after the epdm membrane?
i'd like to be able to install some ceramic and make some paths ..then maybe some plants
to be seen
please let me know what you think of my idea
maybe it is completly stupid
ah yeah also, could you guys please point out SIP manufacturers in my region? would prefer in canada..east ( Qc , ON and NB/NS ) or up states
vermont, maine, NY for shipping reasons
and i'd also like to have a quick idea of the rough price of those pannels?
in standard depth ( 6 -8 " ? ) per square ft :)
thanks all for your time!
JIN |
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cmkavala
Registered Users
Posts:804
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| 04/23/2008 12:33 PM |
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JIN;
sounds by your description cost is no object ?
8" steel SIPs can easily span 18 ft. with a 60 PSF load and are available in one piece up to 53ft. You will need your engineer to evaluate the exact load requirements in order to determine spacing of supporting bar joists.
idea is not stupid, but does sound expensive |
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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JinMTVT
Registered Users
Posts:12
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| 04/23/2008 5:59 PM |
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what makes you think it is expensive?
am i missing something here? SIPs are very expensive ?
what else would you use?
i don't believe that i'd have any problem with a 4' spacing of the joists then ...to be seen
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cmkavala
Registered Users
Posts:804
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| 04/24/2008 8:39 AM |
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Jin;
It's not the sips that will drive up the cost , its the bar-joist, steel pan and lightweight concrete floor. what kind of commercial building is this? |
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Chris Kavala
chris@southernsips.com
1-877-321-SIPS |
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Joe Westfall
Registered Users
Posts:8
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| 04/24/2008 6:16 PM |
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| you haven't discussed the live load requirement for this portion of your project; i would make certain you have a structural engineer assist with this. we manufacture a 12" R-50 roof panel and can carry a huge live load due to the way we build our panel. we use sructural galvanized steel and EPS; check us out on the web at www.greensourceproducts.com. the structural engineer will be your salvation; spend the $$$ now and you won't regret it. you can tap into your local engineering dept. at a local college and give your project to a grad student to help out and keep your $$$ exposure down. |
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JinMTVT
Registered Users
Posts:12
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| 04/24/2008 10:14 PM |
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cmkavala: not the sips ? up to what i have seen so far, sips are almost more expensive than steel joists at the lineair ft :p
i have discussed today with a local company dealing in roof and EPS
they do have a single sided engineered wood EPS pannel that is available in different thickness
and the guy i discussed with recommended me a 1 or 2 pieces EDPM sheet for waterproofing , i am still wondering about the use of this product
as a finition on wich we will walk ..my guess is the roof will need some additional layer to be able to accept human walk paths without puncture in the sheet
i have planned to finish the roof as a terrasse, so loads for regular deck applies i guess
+ we do get a lot of snow in here, wich need to be accounted for also
the other complication could be to get this long roof drain properly
some foam companies seems to be offering precut EPS for drain angles ..could be usefull
Joe Westfall: i do have some minimal engineering background, thing is that i do not want to invest in engi services until i am setup on what i want to use
and that won't happen before i get quotings from a few different companies
i've already settled on 2 different windo manuf,
2 different ICF
now waiting to find the correct company for steel joists
and then i'll work on completing roof design
and when that is done, i'll have an engineer take a look at all that
and approve all of my decisions and make changes where required
anybody knows the canada/quebec code for dead/live loads for roof terrasse ?
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GeorgiaTom
Registered Users
Posts:130
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| 04/25/2008 7:48 AM |
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Jin;
there is more to a system than just the bare cost of bar joist or a sips panel than just the lft. cost.
when they are properly sized ( by a real Engineer) then one can make an informed decision after including all the components for both systems |
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JinMTVT
Registered Users
Posts:12
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| 04/29/2008 12:00 AM |
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Just been insulted by local SIP manufacturer ...
dind't want to do anything with my project at all
i was told that my plan was not pro enough
even though i had mentionned that a regular dwg or 2d plan
was impossible to output from my 3d software ..
too bad for them
please suggest good sip manufacturer in eastern Canada !
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Rsipgeo
Registered Users
Posts:16
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| 05/03/2008 7:44 AM |
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I'm not sure why you would want to use sips if you already have a metal and concrete deck. It's much cheaper just to buy sheets of poly iso insulation and lay that down. It's even cheaper to spray the underside of the roof with foam. Let your concrete and metal deck take the load and then treat the insulation differently. Personally I would not use a SIP on a low slope roof. If there is ever a leak you'll never know it until the structure part of your SIP is gone (if it is an OSB SIP).
So if you want to expose the underside of your roof structure - then poly iso and roof board on top.
If you are going to cover it up - then spray foam underneath and EPDM on top.
If your going to walk on your roof maybe torchdown is the best with a white elastomeric coating. Much thicker. Or a traditional deck on sleepers. |
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JinMTVT
Registered Users
Posts:12
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| 05/03/2008 3:09 PM |
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Rsipgeo: please elabrate on elastometric and deck on sleepers ..
we are going to walk it ..probably even all year long
i received quotations from steel joists manufacturer..and will probably go that way
the 2 first floors will be concrete composite steel deck
but the rook will be only steel deck as i can't afford the concrete and the joists required to hold it up
and i would have to isolate the concrete from the cold..so there is just no point
right now i'd probably do a slopped EPS thick foam system on wich i am going to laminate/glue some osb
or find a company that can do it for me ( got some answers from 3M and some of their waterbased contact cement will do the job quite fine and can be rolled on )
still waiting on quotations from eps companies ... i will also use the glued pannels to construct the structure for the roof access ( 15 by 20 with a 9' wide patio door and some windows )
should i even consider EDPM if we are to walk on it ?
or would elastometric be safer?
can we "blow torch" elastometric on top of an osb without risks ?
maybe juse add an alsphatic paper before ??
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