excellent presentation and step by step . I love Austin ...6th street?...anyway , leaving the airspace between the lath and the metal should actually decrease the probablility of condensation from my experience. Airflow is the name of the game and you have that. You may want to contact Tremco and see if they still have a program for estimating condensation problems before construction. good job on the video ! did you use a flip?
@uva3rdgen Yes it's a Kynar 500 factory painted roof. That Kynar coating has a very good reputation for longevity. The coating holds perfectly under foot traffic, and is slightly slick but holds well under foot when dry. I'll shoot a future video and show you the gutters and rainwater catchment system. Thanks, Matt
Great presentation. Will be very little heat gain or loss through this roof. What kind of support do you recommend under the polyiso foam boards? Is the roof area too hot for using extruded polystyrene in place of polyiso boards?
@Rockytxv The support under the ISO is full 1/2" roof plywood. I would think you could use Extruded Polystyrene as well, that would be less expensive. It will get hot under that roof even with the 3/4" lath, I would expect the top of the foam to be upwards of 120 degrees on a hot July day. -Matt
I'm building a mobile tiny house in San Antonio that will move to a temp zone 4 with lots of snow at some point. In my case would it be better to put the ice and water shield directly on the OSB decking, then install the foam?
@johnnymac1976 Interesting project! I think you could go either way, the benefit of the ice/water shield on top that any water that does get by the metal roof goes on top of the ice/water shield and is directed off the roof. If you ran it under the foam you might tend to trap more water long term. It's probably ok either way though. Matt
Very nice work. I would not have thought of using a herringbone or slanting layout like this. Solves the issue of locating the lath directly under the roof panel seams. You mentioned using 6.5" of spray foam under the roof. Is this open-cell foam to allow drying to the inside? With a under 0.1 perm peel-n-stick there would not be any exterior drying. I know this is a low risk with the waterproofing used but still possible, especially once the owner takes possession (satellite dish, etc.).
@Bigrignohio Yes, I think Open Cell foam is the way to go for our Hot/Humid climate zone. It could in theory dry to the inside but the idea of the full peal/seal is that you'll have little chance for a leak. It's certainly not as forgiving an old school vented roof but this certainly will be VERY efficient. -Matt
Also...there are many penetrations in the roof when you install the 45 degree lath strips. Do you think this is overkill for the long run perspective when you consider how much extra material you use for this system and the fact that this many penetrations greatly increases your chance for a leak?
@boardman4ever101 True we do have more penetrations, but that's the reason for the Water & Ice protection membrane. It's a self sealing product that should last the length of the metal roofs life. The 3/4" air space gives any water that gets into that space the ability to dry or drain. This really is a best practice method for roofing in this climate zone. Matt Risinger
I live in Austin and on location at this home a week ago one of your foreman told me that on another project you had an issue with the ice and water shield breaking down under the extreme Texas heat and solar radiation. This eventually created a leak in a valley, and internal water damage. He said you had had bone back to good old 30# tar paper under the 45 degree lath strips as a result......is this correct?
@boardman4ever101 That's partially true. The home you are talking about had 2" of rigid foam, then WIP HT, then a dark metal roof with no air gap. We had a wall flashing issue where the valley dumped onto a flat roof and when we investigated we found the WIP HT was badly degraded after only 1 year. We made the decision to pull the dark metal roof, rip off the WIP HT and go back with double 30lb felt but we added lath to create a 3/4" air space like what you see in this video. Matt
Thanks Matt, that does make a lot of sense. Sounds like borderline poor design put the builder and product in an unfavorable position. What is your take on using 1 or 2 layers of 30# felt under the lath strips if budget is an issue?
ok the slats were where this guy went way wrong!!! CONDENSATION!!!!! IS WHAT IS GOING TO HAPPEN UNDER THIS STEEL!!!! BECAUSE YOU CAN NOT HAVE A SPACE BETWEEN THE STEEL OR IT WILL SWEAT LIKE A SODA CAN!!! WHEN IT GETS HOT THEN GETS COLD THE ROOF TENDS TO CONDENSATE UNLESS THERE IS NO SPACE BETWEEN AND THIS GUY REALLY MESSED THIS UP BECAUSE NOW EVERY YEAR ITS GOING TO GET THE 3/4 BOARD WET NO MATTER WHAT.... I FEEL SORRY FOR THE PERSON WHO BUYS THIS HOUSE...
@nadroj540 I see what you're saying but I don't see why it would condense on the backside. We've got 2" of foam on the roof top then 5.5" inside so there is little chance the house will be cooling the metal from leaked AC. That metal roof should be the same temp on the top and bottom sides. If condensation does occur there is a 3/4" air space vented top & bottom to bring that moisture out. This is really best practice method for doing a metal roof in our climate zone. -Matt Risinger
Didn't see if plumbing vents.? Are the integrated into 3/4" void.? Good video, nice to break up into pieces and tell us...kept my attention. good job.
excellent presentation and step by step . I love Austin ...6th street?...anyway , leaving the airspace between the lath and the metal should actually decrease the probablility of condensation from my experience. Airflow is the name of the game and you have that. You may want to contact Tremco and see if they still have a program for estimating condensation problems before construction. good job on the video ! did you use a flip?
1
bobmcalister 2 weeks ago
Did you say that they coated the metal roofing in KYNAR? Holy top of the line batman!
Three questions:
How did the coating hold up when walking on it?
How slick was the KYNAR coating?
Can you show us how the gutters were hung?
uva3rdgen 2 months ago
@uva3rdgen Yes it's a Kynar 500 factory painted roof. That Kynar coating has a very good reputation for longevity. The coating holds perfectly under foot traffic, and is slightly slick but holds well under foot when dry. I'll shoot a future video and show you the gutters and rainwater catchment system. Thanks, Matt
MattRisinger 2 months ago
Great presentation. Will be very little heat gain or loss through this roof. What kind of support do you recommend under the polyiso foam boards? Is the roof area too hot for using extruded polystyrene in place of polyiso boards?
Rockytxv 2 months ago
@Rockytxv The support under the ISO is full 1/2" roof plywood. I would think you could use Extruded Polystyrene as well, that would be less expensive. It will get hot under that roof even with the 3/4" lath, I would expect the top of the foam to be upwards of 120 degrees on a hot July day. -Matt
MattRisinger 2 months ago
I'm building a mobile tiny house in San Antonio that will move to a temp zone 4 with lots of snow at some point. In my case would it be better to put the ice and water shield directly on the OSB decking, then install the foam?
johnnymac1976 3 months ago
@johnnymac1976 Interesting project! I think you could go either way, the benefit of the ice/water shield on top that any water that does get by the metal roof goes on top of the ice/water shield and is directed off the roof. If you ran it under the foam you might tend to trap more water long term. It's probably ok either way though. Matt
MattRisinger 3 months ago
Very nice work. I would not have thought of using a herringbone or slanting layout like this. Solves the issue of locating the lath directly under the roof panel seams. You mentioned using 6.5" of spray foam under the roof. Is this open-cell foam to allow drying to the inside? With a under 0.1 perm peel-n-stick there would not be any exterior drying. I know this is a low risk with the waterproofing used but still possible, especially once the owner takes possession (satellite dish, etc.).
Bigrignohio 4 months ago
@Bigrignohio Yes, I think Open Cell foam is the way to go for our Hot/Humid climate zone. It could in theory dry to the inside but the idea of the full peal/seal is that you'll have little chance for a leak. It's certainly not as forgiving an old school vented roof but this certainly will be VERY efficient. -Matt
MattRisinger 4 months ago
Also...there are many penetrations in the roof when you install the 45 degree lath strips. Do you think this is overkill for the long run perspective when you consider how much extra material you use for this system and the fact that this many penetrations greatly increases your chance for a leak?
boardman4ever101 6 months ago
@boardman4ever101 True we do have more penetrations, but that's the reason for the Water & Ice protection membrane. It's a self sealing product that should last the length of the metal roofs life. The 3/4" air space gives any water that gets into that space the ability to dry or drain. This really is a best practice method for roofing in this climate zone. Matt Risinger
MattRisinger 6 months ago
I live in Austin and on location at this home a week ago one of your foreman told me that on another project you had an issue with the ice and water shield breaking down under the extreme Texas heat and solar radiation. This eventually created a leak in a valley, and internal water damage. He said you had had bone back to good old 30# tar paper under the 45 degree lath strips as a result......is this correct?
boardman4ever101 7 months ago
@boardman4ever101 That's partially true. The home you are talking about had 2" of rigid foam, then WIP HT, then a dark metal roof with no air gap. We had a wall flashing issue where the valley dumped onto a flat roof and when we investigated we found the WIP HT was badly degraded after only 1 year. We made the decision to pull the dark metal roof, rip off the WIP HT and go back with double 30lb felt but we added lath to create a 3/4" air space like what you see in this video. Matt
MattRisinger 7 months ago
Thanks Matt, that does make a lot of sense. Sounds like borderline poor design put the builder and product in an unfavorable position. What is your take on using 1 or 2 layers of 30# felt under the lath strips if budget is an issue?
boardman4ever101 7 months ago
ok the slats were where this guy went way wrong!!! CONDENSATION!!!!! IS WHAT IS GOING TO HAPPEN UNDER THIS STEEL!!!! BECAUSE YOU CAN NOT HAVE A SPACE BETWEEN THE STEEL OR IT WILL SWEAT LIKE A SODA CAN!!! WHEN IT GETS HOT THEN GETS COLD THE ROOF TENDS TO CONDENSATE UNLESS THERE IS NO SPACE BETWEEN AND THIS GUY REALLY MESSED THIS UP BECAUSE NOW EVERY YEAR ITS GOING TO GET THE 3/4 BOARD WET NO MATTER WHAT.... I FEEL SORRY FOR THE PERSON WHO BUYS THIS HOUSE...
nadroj540 7 months ago
@nadroj540 I see what you're saying but I don't see why it would condense on the backside. We've got 2" of foam on the roof top then 5.5" inside so there is little chance the house will be cooling the metal from leaked AC. That metal roof should be the same temp on the top and bottom sides. If condensation does occur there is a 3/4" air space vented top & bottom to bring that moisture out. This is really best practice method for doing a metal roof in our climate zone. -Matt Risinger
MattRisinger 7 months ago
Didn't see if plumbing vents.? Are the integrated into 3/4" void.? Good video, nice to break up into pieces and tell us...kept my attention. good job.
largeview 7 months ago
@largeview Thanks for your kind comments. The plumbing vents do penetrate the roof and terminate above the metal. Best, Matt Risinger
MattRisinger 7 months ago
Do you "screen" to keep bees out?
Sirfloatsalot1 8 months ago
Do you "screen" to keep bees out?
Sirfloatsalot1 8 months ago
Do you "screen" to keep bees out?
Sirfloatsalot1 8 months ago
nice work matt & roofer!
lexichronicle2 8 months ago
Super good job.
tapoole2000 8 months ago
cool
iamaGod357 8 months ago