I used Certainteed Membrane on the ceilings of my house and Siga Majvest in the walls. All of my lights and such got taped with Siga Rissan tape and although my mini splits aren’t running yet, a small window air conditioner cools my whole main floor about 1000 square feet. Can’t wait to see how it does for heating this winter.
Great explanation, we do a lot of cathedral ceilings and use a 1/2 wood fibre panel as our vent baffle 2-3” below the underside of our roof deck. We install a smart membrane, Intello or Majrex against the interior ceiling side of the truss followed by a service cavity which is key for maintaining airtighness without penetrations.
I can’t see ANY roof venting on our hot dry southern New Mexico climate vaulted ceiling?!! There sure doesn’t seem to be any soffit vents. There might be a ridge vent. I’ll climb into the attic and look closer. Are houses sometimes built without roof vents in the dry desert. It’s only slightly humid for about two months during monsoon and dries out in-between rain storms. Also the attic appears to be unvented except for the ridge vent if there is one. The attic gets very hot so I’ve been planning on venting it somehow. Any suggestions? Thanks for the series. I subscribed.
I have built a separate extention to our cabin where it is from inner side 45x300 LVL beams with C-C 900mm and in top of those a 12mm plywood sheet making it a closed roof. I was first planning to fill up with 300mm thick mineral wool. But now I am consider to glue a 50 or 100mm EPS towards the plywood with PU foam around each so it gets air tight, and then 200mm of Mineral wool. during winter it will normally be around 25-35 minus degress outside and 20-25 degrees inside, so it will be a bigg difference in temperature, so I was thinking that with 50 or 100mm EPS towards the outer layer the condensation point will be inside the EPS instead of inside the mineral wool. Please give advice if you have time, I was planning to do these parts in around 3-4 weeks. Edit: on the inside of Mineral wool I was planning to add a membrane that will keep moist from going in to the mineral wool)
Does the ceiling air / vapor control layer need to connect directly to the wall air / vapor control layer by wrapping the top plate in some way? Thanks for the videos! Consistently more informative and applicable than other building science channels
@@brennangran2763 Thanks for watching, and great question. The answer is yes, and whether that layer is located on the exterior or on the interior is going to entirely depend on the design of the assembly - but it needs to connect to whatever is serving as the primary air barrier in that wall assembly.
For my house I am leaning towards using plenum trusses on the second floor. Sheath the bottom of the plenum trusses with taped zip, install the ducts and then cover with framing and drywall. The perimeter would be airsealed with additional zip or possibly Majrex.
Great info, but is this video geared towards cold weather climates? The location of the membranes depicted don’t appear to be beneficial in a hot and humid climate.
Does the Oregon building code still allow HVAC ducts to be placed in a vented (untempered) attic or crawl space? I know it’s bad practice and that model building codes have moved away from this formerly common practice. Just wondering if OR code has gotten there yet. Thanks.
Just in the process of buying a house, generally very well-built and decently insulated, but the roof is vented. I’m considering either installing baffles and air sealing with spraycans or foamboards as you suggested , but also converting the entire space to be a conditioned attic. But it being a truss, I don’t gain free extra space or anything. Bit nervous about the second because I’d be making it pretty major change system that has already been working successfully for a long time . Is there any downside to installing baffles air sealing and then basically adding as much insulation as I can get away with? All the mechanicals are in the basement , so no issue there
Sounds like a lot of work for little gain to me but I’m not THE expert. If you have a air gap I dont think you need the baffles. If it’s not broken dont fix it.
I believe there are a couple out there, but I'd probably just fasten 1/2" foil faced rigid insulation to the underside of the top chords instead of hunting down a reflective baffle product.
I used Certainteed Membrane on the ceilings of my house and Siga Majvest in the walls. All of my lights and such got taped with Siga Rissan tape and although my mini splits aren’t running yet, a small window air conditioner cools my whole main floor about 1000 square feet. Can’t wait to see how it does for heating this winter.
Great explanation, we do a lot of cathedral ceilings and use a 1/2 wood fibre panel as our vent baffle 2-3” below the underside of our roof deck. We install a smart membrane, Intello or Majrex against the interior ceiling side of the truss followed by a service cavity which is key for maintaining airtighness without penetrations.
I can’t see ANY roof venting on our hot dry southern New Mexico climate vaulted ceiling?!! There sure doesn’t seem to be any soffit vents. There might be a ridge vent. I’ll climb into the attic and look closer. Are houses sometimes built without roof vents in the dry desert. It’s only slightly humid for about two months during monsoon and dries out in-between rain storms. Also the attic appears to be unvented except for the ridge vent if there is one. The attic gets very hot so I’ve been planning on venting it somehow. Any suggestions? Thanks for the series. I subscribed.
I have built a separate extention to our cabin where it is from inner side 45x300 LVL beams with C-C 900mm and in top of those a 12mm plywood sheet making it a closed roof. I was first planning to fill up with 300mm thick mineral wool. But now I am consider to glue a 50 or 100mm EPS towards the plywood with PU foam around each so it gets air tight, and then 200mm of Mineral wool. during winter it will normally be around 25-35 minus degress outside and 20-25 degrees inside, so it will be a bigg difference in temperature, so I was thinking that with 50 or 100mm EPS towards the outer layer the condensation point will be inside the EPS instead of inside the mineral wool. Please give advice if you have time, I was planning to do these parts in around 3-4 weeks.
Edit: on the inside of Mineral wool I was planning to add a membrane that will keep moist from going in to the mineral wool)
Does the ceiling air / vapor control layer need to connect directly to the wall air / vapor control layer by wrapping the top plate in some way? Thanks for the videos! Consistently more informative and applicable than other building science channels
Matt Risingers latest video named "Mountain Build with a View" tours a house that does this.
If you’re building new and can, yes.
@@brennangran2763 Thanks for watching, and great question. The answer is yes, and whether that layer is located on the exterior or on the interior is going to entirely depend on the design of the assembly - but it needs to connect to whatever is serving as the primary air barrier in that wall assembly.
For my house I am leaning towards using plenum trusses on the second floor. Sheath the bottom of the plenum trusses with taped zip, install the ducts and then cover with framing and drywall. The perimeter would be airsealed with additional zip or possibly Majrex.
Great info, but is this video geared towards cold weather climates? The location of the membranes depicted don’t appear to be beneficial in a hot and humid climate.
Does the Oregon building code still allow HVAC ducts to be placed in a vented (untempered) attic or crawl space? I know it’s bad practice and that model building codes have moved away from this formerly common practice. Just wondering if OR code has gotten there yet. Thanks.
Just in the process of buying a house, generally very well-built and decently insulated, but the roof is vented.
I’m considering either installing baffles and air sealing with spraycans or foamboards as you suggested ,
but also converting the entire space to be a conditioned attic. But it being a truss, I don’t gain free extra space or anything.
Bit nervous about the second because I’d be making it pretty major change system that has already been working successfully for a long time .
Is there any downside to installing baffles air sealing and then basically adding as much insulation as I can get away with?
All the mechanicals are in the basement , so no issue there
Sounds like a lot of work for little gain to me but I’m not THE expert. If you have a air gap I dont think you need the baffles. If it’s not broken dont fix it.
Does anyone sell baffles that have radiant barrier stuck to one side?
I believe there are a couple out there, but I'd probably just fasten 1/2" foil faced rigid insulation to the underside of the top chords instead of hunting down a reflective baffle product.
annoying 'music' - why?