I dont trust the 4 inches of foam to support the interior
load bearing walls. I dont care how the engineering calcs works out... 40 or 50 years down the road I would want a firm footing under the walls. My knee jerk replacement would be 6x6 pressure treated posts laid on their sides below the load walls. I doubt the thermal
conductance through the floor 6x6 posts is even measurable.
Because the floor was not adjusted narrower because of the
two sistered floor joists when it comes time to put the end walls on the shed the walls are going to be 3 inches longer and cannot use a perfect multiple of 2 feet. It would be better to trim the
floor joists by 3 inches
It is real simple. You either manage the form contractor yourself
or you pay the concrete contractor to do it for you at extra charge.
Consider hiring a general contractor to build the house for you
and you wont have any work at all..... but you will have much less
Although The possibility of adding extra joists under the island was mentioned, there are two ways or possibly both together of doing this and one is for instance switching from 16" on center to 12" on center and or "sistering" another joist(s) right beside the existing
joists so they are all double where you need them. Also, if you were going to go to the trouble to add strongbacks beneath the joists you might as well use a deeper joist in that area such as 18 or 20 inch instead of 14 inch in the area needed. Stiffness increases as the cube of the depth of the beam. Double the depth and you get only one eighth of the deflection. This may have been first appreciated in airplane wings.
This might be a great idea but I cannot understand it without
pictures and drawings etc. Please provide illustrations.
There is an overwhelming amount of technical info that is missing here. Different chemicals are used in open cell and
closed cell foams and even among each type there are several
different formulations and there are additive chemicals sometimes such as fire retardant and chemicals which adjust
the optimum curing temperatures etc. I wonder also if what
they are actually referring to is the more accurately used
term of poly-isocyanurate which is a two part closed cell
foam where before curing one of the components contains
cyanide and after curing it is supposedly transformed into
a safer chemical. I do know that when this foam is burned
a cyanide gas is given off and when only one whiff is taken
you are dead. So it is rarely mentioned or talked about
as far as how dangerous the closed cell foams are in the
event of a fire. There is no such thing as someone stumbling out of a house coughing and choking from breathing smoke.
There really needs to be some very specific laboratory
analysis for each specific foam mixture and measurements of
off-gassing after installation much like they did years
ago when there was a lot of formadelhyde used in the glue
of primarily plywoods and particle boards used in cabinets
and paneling and kitchen countertops and other furniture components etc. A point I wish to make is that I
suspect of all the 2 part foam formulas used, we need
to identify which are the best and which are the worst
and then prohibit the use of the worst.
I am an ex custom home builder and have used the closed cell
foam many times. I know that basically the same stuff
( polyisocyanurate) is also used on commercial roofs and commercial refrigeration such as warehouses, box-cars,
refrigerated trucks, and convenience store and grocery
store cold storage rooms etc.
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