ustmd
Platinum Member
Yes--that is what we did
One thing--stable well. If you have good air flow through the attic, over time, the stables can rip out
Radiant Barrier in Attic
- Thread starter dieselscout80
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Yes--that is what we did
One thing--stable well. If you have good air flow through the attic, over time, the stables can rip out
OP
dieselscout80
Veteran Member
I wonder if those capped nails they use for house wrap would be good to use or a strip of wood with nails or screws?
SPIKER
Elite Member
One thing if you have ridge vents AND side vents on the sides of them then you could run the Radiant barrier up and over the peak and back down the other side. you would need a flat across the peak so there is opening lengthwise between ALL of the trusses this will bring the HOT air up to the peak and out the vent NOT into the attic space like it would if there is an opening back into the attic space.
The SIDE vents will then pull in enough cool air into the space under the radiant insulation to keep that space conditioned to meet outside temps better. the radiant is reflecting much of the heat waves back out towards the roof and space BUT it will also warm up the underside of the roof causing convection heating (air pulls up from bottom and out top if it open to the room.
Mark
The SIDE vents will then pull in enough cool air into the space under the radiant insulation to keep that space conditioned to meet outside temps better. the radiant is reflecting much of the heat waves back out towards the roof and space BUT it will also warm up the underside of the roof causing convection heating (air pulls up from bottom and out top if it open to the room.
Mark
OP
dieselscout80
Veteran Member
When you say side vents are you refering to vents in the soffit?
If you are then yes I have soffit vents, a full length ridge vent and gable vents at both ends of the peak of the roof.
CornReaper
New member
When your house has a ridge and soffit vent as explained in the scenario above, you should not run the insulation all the way down to eaves and across the ridge. You will impede or could impede the natural air exchange, the whole reason to have the vents in the first place. Stop the insulation about 8" away from the eaves or insulation if you have any and the same distance from the ridge. If you don't have ridge/soffits you can run the insulation up and down the rafters with no breaks. Hopefully you have louvres or something to allow some air exchange. In most cases use the perforated product, tiny pinholes, to allow moisture transfer. For your barn insulation, there is another type of radiant barrier with cellular construction (thickness) that will give you an R-Value as well. This material is solid. Installing it gives you a vapor barrier and will slow or eliminate condensation in your out buildings.
OP
dieselscout80
Veteran Member
I'm not going to put insluation just a radiant barrier.
Gary Fowler
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A radiant barrier will help with attic temperatures during the summer but without some ceiling insulation it wont be enough to keep you cool in summer or warm in winter. I have the radiant barrier in the ceiling of my shop plus bat insulation between the rafters and in the walls and the mylar radiant barrier on top of the insulation. In my house, I have the same but with bat insulation between the rafters, then 12-18" of blown in fiberglass on top of that then the mylar film radiant barrier on top of the blown in insulation. The roof has radiant barrier full length from center ridge vent to soffit eaves.
You can see in the second photo how the front porch has it installed also in total roof area and walls. This actually went on first then the roof decking on top of it.
My shop just has 8" bat in walls and ceiling and of course the roof radiant barrier with the mylar radiant layed loosely on top of the bat insulation. This was an after build scheme that we went for in hopes of saving additional energy costs. Not sure if it is helping much more than than just the barrier and insulation and it was super costly. Possibly I should have just invested in more insulation for the cost. Insulation is cheap compared to energy cost.
My shop does pretty well with what it has and stays above freezing with no heat and comfortable with a 1500 watt heater running during winter and that only runs part time. Summer time, I can cool the whole thing to a comfortable 80F with a 14,000 BTU window unit.
You can see in the second photo how the front porch has it installed also in total roof area and walls. This actually went on first then the roof decking on top of it.
My shop just has 8" bat in walls and ceiling and of course the roof radiant barrier with the mylar radiant layed loosely on top of the bat insulation. This was an after build scheme that we went for in hopes of saving additional energy costs. Not sure if it is helping much more than than just the barrier and insulation and it was super costly. Possibly I should have just invested in more insulation for the cost. Insulation is cheap compared to energy cost.
My shop does pretty well with what it has and stays above freezing with no heat and comfortable with a 1500 watt heater running during winter and that only runs part time. Summer time, I can cool the whole thing to a comfortable 80F with a 14,000 BTU window unit.
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SPIKER
Elite Member
With the Soffit and Gable Vents then you can run the radian barrier from attic floor to peak & back to floor. the Peak should have a free air space below the peak vents so all the rafters can get a common airspace. Seal up the airspace between the roof and the attic to prevent thermal transfer via convection. the heat trapped between the roof and the radiant insulation will escape thru the peak vent & replaced by the air coming in under the sides & soffit. The Gable Vents should be enough for for the attic if not you may need a powered solar type vent in one of them on the south side to pull air out, same for near the peak in the roof a powered solar type would help a lot. \
Mark
Mark