Insulation, Radiant and Vapor Barriers - Insulation between floor trusses
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ScottMA
02-19-04, 08:57 AM
Hello all,
I want to insulate a my floor, which is over an unfinished basement. There is no insulation there now. I plan to use faced fiberglass batts between the joists.
I do not have 2x floor joists, I have 20-inch deep floor trusses (the kind made of short sections of 2x4s).
So if I install batts, I will basically have 3.5 inch gaps in my insulation with nothing but a 1.5 inch thick 2x4 against the floor.
So, finally here is my question. Is my insulation going to be effective? Should I try to do something "inside" the trusses, between the 2x4 members? Or rethink the whole plan?
Thanks,
Scott
I want to insulate a my floor, which is over an unfinished basement. There is no insulation there now. I plan to use faced fiberglass batts between the joists.
I do not have 2x floor joists, I have 20-inch deep floor trusses (the kind made of short sections of 2x4s).
So if I install batts, I will basically have 3.5 inch gaps in my insulation with nothing but a 1.5 inch thick 2x4 against the floor.
So, finally here is my question. Is my insulation going to be effective? Should I try to do something "inside" the trusses, between the 2x4 members? Or rethink the whole plan?
Thanks,
Scott
Ed Imeduc
02-19-04, 01:54 PM
Why insulate the floor? dont you have the furnace and all that down there in the basement now? Id rethink this for sure. if you do, put the paper side to the floor or to the room above. ED
ScottMA
02-19-04, 02:26 PM
Maybe I should I have been clearer...
The portion of the floor I want to insulate is over a garage. The garage is separated from the rest of the basement by an insulated wall. There needs to be insulation over the garage, it is hot in summer, cold in winter.
My concern is that the efficiency of the faced fiberglass will be lessened a great deal by the nature of the floor trusses (i.e. I don't have a 2x8 or 2x10 against the floor to insulate between, but instead the open structure of the truss).
I was just wondering what the standard practice was, given that these type floors seem to be pretty common in newer homes.
The portion of the floor I want to insulate is over a garage. The garage is separated from the rest of the basement by an insulated wall. There needs to be insulation over the garage, it is hot in summer, cold in winter.
My concern is that the efficiency of the faced fiberglass will be lessened a great deal by the nature of the floor trusses (i.e. I don't have a 2x8 or 2x10 against the floor to insulate between, but instead the open structure of the truss).
I was just wondering what the standard practice was, given that these type floors seem to be pretty common in newer homes.
Ed Imeduc
02-20-04, 11:44 AM
Id put the paper side to the floor or the room side here for sure. If you stop and think the walls of the home have a 1.5 stud on all the outside wall that insulation dont cover. I dont see how you will lose that much through the 2 by on the floor. put a pad and rug down on the floor there.
Or like code here the floor truss would have to have 5/8" drywall on it for fire delay to the home. Id take and blow 6"cellulose on top of the drywall ceiling of the garage. This would cover the flat 2x4 floor joist ED
Or like code here the floor truss would have to have 5/8" drywall on it for fire delay to the home. Id take and blow 6"cellulose on top of the drywall ceiling of the garage. This would cover the flat 2x4 floor joist ED
wildfire6460
02-20-04, 07:20 PM
Cellulose is always the best option, in my opinion. Be sure to block the joist ends with fiberglass if you go this route.....
If you insist on going with batts, there are two options. You can push the insulation to the subfloor and hold it there with wires. The drawback to this is that it's hard to remove all gaps and to find a place to secure the wires. The second option is to leave the batt near the bottom of the floor truss and lay the wire across the bottom of the trusses (if it is to remain exposed) . Fold the insulation up at the joist ends to "seal." This leaves fewer gaps but also creates "dead air," an area where there is no air circulation. It also depends on the local code as to which method is preferred.
If you insist on going with batts, there are two options. You can push the insulation to the subfloor and hold it there with wires. The drawback to this is that it's hard to remove all gaps and to find a place to secure the wires. The second option is to leave the batt near the bottom of the floor truss and lay the wire across the bottom of the trusses (if it is to remain exposed) . Fold the insulation up at the joist ends to "seal." This leaves fewer gaps but also creates "dead air," an area where there is no air circulation. It also depends on the local code as to which method is preferred.