Thanks very much...Kate wonders if you ever used this
as an installer or had it done to your house/building?
Rich and Kate
--- In DoIt_Yourself@yahoogroups.com, "Strat" wrote:
>
> "mountain953346" wrote:> HI Strat..thanks for the great analysis and
> ideas you wrote..appreciate very much...I like all your options!
> > Question though on the the closed cell foam sheathing..
> > Is it walkable on?YES
> > I wonder about the vertical strength if applied over the exisiting
> roofThat is "Deflection
>
TF-8&tbm=isch&source=og&sa=N&tab=wi&authuser=0&ei=yqUSUYmmKc_QqAGCsoGwAQ\
> &biw=1440&bih=815&sei=zaUSUdfOI8XVrQHz54HgDA> -limits"
> > Wont it be pretty compressible? NO, you can walk on it and unless
> you weigh 1,000 lbs, your shoes won't leave an imprint.
> Read More . . . Two ways to answer you, a simplified common sense
> approach, and the engineering approach which will involve lots of
> figures and math that's beyond the scope of this forum. But I'll
> include links to a couple of web resources for those who are inclined to
> read through the fine detailed analysis on their own.
> If you are confident to walk on your current roof, then you'll be happy
> to know that after spraying top of your deck with 2 to 3" of "ccSPF",
> the overall deflection limit is going to be 1.5 to 3 times (depends on
> the thickness of foam) that of your current raw lumber deck.
> If you want exact figures, research deflection-limit for your 1x8 wood
> roof, identify specie of wood, it'll take some work if you're
> interested). I couldn't find data on 1x8 planks as structural material
> because today's building codes don't allow anything less than OSB boards
> nailed to 2x4" studs.Anyway, whatever you come up with for your 1x8
> deck, multiply it by a factor of 1.5 to 3 and that's how much stronger
> your roof will be after sparying ccSPF.
> Here are a couple of great pages to review:
>
> * Benefits of ccSPF
> :
> * SPF for in commercial
> buildings
> * Refs: Deflection strength.
>
>
> Hope this helps.BTW. that first link is a real good resource because it
> covers ALL benefits of ccSPF, it covers vapor barrier, condensation,
> structural and insulation benefits.
> -S-
> > > --- In DoIt_Yourself@yahoogroups.com, "Strat" wrote:
> > >
> >
> > > (c)
> > > Another option is applying another layer or two of rigid closed cell
> foam sheathing over existing roof, taping and staggering seams. This
> yields a very good result and very doable by DIY warriors.
> > > This is my most desirable and cost effective option.
> > >
> > >
> > > The other insulation materials like loose cellulose or fiberglass
> batting are not relevant to low pitch/flat roofs because there isn't
> adequate head-room to pack enough insulating material in to make an
> impact on R value.
> > >
> > > http://energy.gov/energysaver/articles/insulation-materials
> > >
> > > Good luck and we'll compare notes comes next Fall.
> > > -S-
> > >
> > >
> > >
> > > --- In DoIt_Yourself@yahoogroups.com, "mountain953346" wrote:
> > > >
> > > > We have 2000 sq ft roof that is composed of 1x8's over
> > > > 4x8 on 8ft centers, then asphalt roll and tar covering the 1x8's.
> > > >
> > > > That's it. There is no insulation and we are loosing most
> > > > of AC and heat through the roof.(It is a low-slope "flat" roof)
> > > >
> > > > We have computed the costs for doing a new inside the house
> drywall
> > > > ceiling dropped down 3 1/2" with r-15 fiberglass insulation
> > > > at about $1.25 a sq ft. minus labor..having done drywall
> > > > before we are confident to do the work although it seems
> > > > a lot more intensive than adding new roof...??
> > > >
> > > > Add roof approach is to add 2x4s on 16in centers on the roof
> > > > and put insulation there, then cover with 3/8" CDX and asphalt
> > > > roll roofing over that which is now on the existing roof
> > > > (maybe 25 year old roof now so could use a replacement)...
> > > > essentially making a new roof....we also have done DIY
> > > > in this area. Costs of materials about the same.
> > > >
> > > > It seems to me that the roof approach is way less labor
> > > > intensive than beaming the inside ceiling, juggling
> > > > even lightweight drywall, insulating and screwing and taping
> > > > and mudding the inside ceiling...
> > > >
> > > > I would be very interested in the DIY'ers thoughts on the
> > > > approaches to this project...or a new approach we have not
> > > > thought of to solve this upward massive energy drain. In the
> > > > summer the ceiling inside is a virtual radiator. We live
> > > > in San Diego away from coast 15 miles so it gets hot but
> > > > does cool off at night (semi-desert climate).
> > > >
> > > > Thanks in advance for any and all thoughts and ideas.
> > > >
> > > > Rich and Kate.
> > >
> >
>
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