2019 Keystone 5th wheel - TPO lifting issue
Looking to see if others have seen this TPO lifting issue at the left and right side walls of the roof. A little background. I am helping out a neighbor who has a 2019 Laredo 5th wheel. They bought...
Forum Discussion
To Doug and others following along, here is my approach for repairing this TPO membrane lifting problem. The need/goal of repairing this lifting issue now is, after I seal the roof and all the penetrations it will be a long term repair/upgrade. Now is the time to correct this issue rather than later hoping the lift TPO does not get worse.
Since the gutter rail has no butyl tape, either between the TPO and the siding or the gutter rail to the TPO, I will lift off the gutter rail. This is not a big deal to do in this case.
The TPO lifting is at the edge of the radiused sheet metal, fold back the TPO onto the main roof as it is not bonded to the metal and this will expose the lifting staples and the breathing sheet metal.
Remove the staples, install low profile head screws in the sheet metal to the decking. I'm still on the hunt for the right screw, but it would be close to these. A #8 x 1" lg low profile head or lath head screw.
Here at McMaster is one option for low profile heads
https://www.mcmaster.com/low-profile-head-sheet-metal-screws/square-drive-flanged-extra-wide-rounded-head-screws-for-sheet-metal/
Truss washer head, needle point screw from Hillman or others. We have a Hillman dealer locally here in town.
https://shop.hillmangroup.com/ccrz__ProductDetails?sku=82206&cclcl=en_US
I have a belief that trying to use a flat head screw, countersunk in, the sheet metal is so thin, the edges of the screw will pull through sheet metal over time trying to get the screw heads flush. With larger diameter low profile head screw to the drilled hole in the metal, I will get better metal clamping and no sharp edges on the screw head.
After the metal is screwed down, I will apply Eternaprime liquid brushable primer to back side of the the TPO, the glued wood decking, and over the sheet metal area as prep for the area. Eternaprime is recommended on TPO.
Install Eternabond double stick tape onto the decking area starting at the point of the peeling TPO on the decking, screw heads, and run out in width on the sheet metal curve. I would start with 4" wide double stick the and go the length of the camper. There could be some small air bubble pockets as the lifting TPO is not straight. I will see if I can straighten the lift pattern to minimize this. A localized small air pocket is not worse then other small non glued pockets on the roof as long as there is no stress to make the pocket larger.
Fold the TPO membrane over, roll the TPO into the double stick. The purpose of the double stick is to regain a TPO bond to the dried glued decking and the sheet metal curve over the tops of the low profile screws. The double stick should flow slightly over the screw heads and fill/relive any point pressure of the screw head on the TPO.
Apply GSSI MH-10A commercial building butyl (1/8" by 1 1/2") between the siding and the TPO at the gutter rail area.
Line the back side of the gutter rail with GSSI butyl and install the gutter rail back in the same location as it came off. Due to colder shop temps in the winter, gently warm the butyl before application to allow it to flow when the gutter screws are tightened.
When I seal the entire roof, there will be no vinyl screw cover over the gutter screws. The roof sealant will cover over all the screw heads down into the gutter rail and at the top of the gutter rail to the TPO.
Comments welcome pointing out anything I may have missed.
Thanks
John
Since the gutter rail has no butyl tape, either between the TPO and the siding or the gutter rail to the TPO, I will lift off the gutter rail. This is not a big deal to do in this case.
The TPO lifting is at the edge of the radiused sheet metal, fold back the TPO onto the main roof as it is not bonded to the metal and this will expose the lifting staples and the breathing sheet metal.
Remove the staples, install low profile head screws in the sheet metal to the decking. I'm still on the hunt for the right screw, but it would be close to these. A #8 x 1" lg low profile head or lath head screw.
Here at McMaster is one option for low profile heads
https://www.mcmaster.com/low-profile-head-sheet-metal-screws/square-drive-flanged-extra-wide-rounded-head-screws-for-sheet-metal/
Truss washer head, needle point screw from Hillman or others. We have a Hillman dealer locally here in town.
https://shop.hillmangroup.com/ccrz__ProductDetails?sku=82206&cclcl=en_US
I have a belief that trying to use a flat head screw, countersunk in, the sheet metal is so thin, the edges of the screw will pull through sheet metal over time trying to get the screw heads flush. With larger diameter low profile head screw to the drilled hole in the metal, I will get better metal clamping and no sharp edges on the screw head.
After the metal is screwed down, I will apply Eternaprime liquid brushable primer to back side of the the TPO, the glued wood decking, and over the sheet metal area as prep for the area. Eternaprime is recommended on TPO.
Install Eternabond double stick tape onto the decking area starting at the point of the peeling TPO on the decking, screw heads, and run out in width on the sheet metal curve. I would start with 4" wide double stick the and go the length of the camper. There could be some small air bubble pockets as the lifting TPO is not straight. I will see if I can straighten the lift pattern to minimize this. A localized small air pocket is not worse then other small non glued pockets on the roof as long as there is no stress to make the pocket larger.
Fold the TPO membrane over, roll the TPO into the double stick. The purpose of the double stick is to regain a TPO bond to the dried glued decking and the sheet metal curve over the tops of the low profile screws. The double stick should flow slightly over the screw heads and fill/relive any point pressure of the screw head on the TPO.
Apply GSSI MH-10A commercial building butyl (1/8" by 1 1/2") between the siding and the TPO at the gutter rail area.
Line the back side of the gutter rail with GSSI butyl and install the gutter rail back in the same location as it came off. Due to colder shop temps in the winter, gently warm the butyl before application to allow it to flow when the gutter screws are tightened.
When I seal the entire roof, there will be no vinyl screw cover over the gutter screws. The roof sealant will cover over all the screw heads down into the gutter rail and at the top of the gutter rail to the TPO.
Comments welcome pointing out anything I may have missed.
Thanks
John
