Sealing roof hatch

[jjhwick119]

Ok, I know there are posts about this, mostly about the sealants, but I didnt see my question answered so here I am. I need to seal up my roof and I'm pulling the hatches out to cover with some sheet metal and seal em up. I will most likely add vents later, I'm just leaving em sealed for now to start on interior. My question is, what gauge metal should I be using? My interior roof was perforated so that won't work, and the metal we carry at Lowe's is only 26 gauge, which seemed too thin to me, so I wanted others opinions on if it would work, or what size i should be looking for? Thanks.

[skuld]

I got a 4/8 sheet of 14 gauge sheet metal from a local shop for $60. They cut it to the exact sized I needed and gave me the extra (though I haven't found a use for it yet)

Rivets were easy to install, and I put down a healthy amount of polyurethane sealant around the edge. I used the black roofing sealant, but I have no idea what is the difference between the black roofing sealant and white window sealant.

Dicor lap sealant is also commonly used for sealing rooftop A/Cs and fans. I think the polyurethane works a bit better as an adhesive, but in this case the rivets are really what is adhering it, and you just want it sealed.

I did a bit of research between the two, and I still haven't decided what I will use when installing a fan on the roof. I've seen sources say that polyurethane is worse with UV and will eventually crack, and I've seen the same criticism of dicor. Either way, just avoid silicone if you want to do it right.

[Twigg]

Originally Posted by skuld

I got a 4/8 sheet of 14 gauge sheet metal from a local shop for $60. They cut it to the exact sized I needed and gave me the extra (though I haven't found a use for it yet)

Rivets were easy to install, and I put down a healthy amount of polyurethane sealant around the edge. I used the black roofing sealant, but I have no idea what is the difference between the black roofing sealant and white window sealant.

Dicor lap sealant is also commonly used for sealing rooftop A/Cs and fans. I think the polyurethane works a bit better as an adhesive, but in this case the rivets are really what is adhering it, and you just want it sealed.

I did a bit of research between the two, and I still haven't decided what I will use when installing a fan on the roof. I've seen sources say that polyurethane is worse with UV and will eventually crack, and I've seen the same criticism of dicor. Either way, just avoid silicone if you want to do it right.

My windows are sealed with polyurethane, and they don't leak after 18 years. UV can only get at the very edge.

You might consider the butyl tape for a flat surface though.

[BowserJournal]

Originally Posted by jjhwick119

Ok, I know there are posts about this, mostly about the sealants, but I didnt see my question answered so here I am. I need to seal up my roof and I'm pulling the hatches out to cover with some sheet metal and seal em up. I will most likely add vents later, I'm just leaving em sealed for now to start on interior. My question is, what gauge metal should I be using? My interior roof was perforated so that won't work, and the metal we carry at Lowe's is only 26 gauge, which seemed too thin to me, so I wanted others opinions on if it would work, or what size i should be looking for? Thanks.

We bought an arcrylic clear roof cover to fit over the hole. Plus we will end up with a skylight!

[jjhwick119]

I was planning on butyl tape with a bead of seam sealer around the edge. Eventually it will be something i can open and see through, just not right now. I'll cut that hole later.

[dbhost]

Originally Posted by jjhwick119

I was planning on butyl tape with a bead of seam sealer around the edge. Eventually it will be something i can open and see through, just not right now. I'll cut that hole later.

Are you looking at making this permanent, or just as a temporary hole filler until you get the interior built out? If you are planning on reusing the hole for say a roof fan, why not do the install now and work around that?

[jjhwick119]

Temporary for right now. It seems like everything is smaller opening, so I'm sealing and I'll cut in a vent or basic hatch I can open and climb out of, not sure yet, but I'll do that part before I finish the interior roof work. Just want it sealed up now to finish treating rust on floor, painting, and subfloor so they won't get wet, and those are what I plan yo accomplish next. Don't want to jump around projects too much

Basically, I want to put a check mark saying subfloor is done before I complete another project. Since I have to patch it to reduce the hole, I'm just doing the step I need now

Edit - can anyone save me a trip out to the bus to measure. I know the hole cut in the roof is typically 22.5", but I'm not sure how much room I got on top on the sides, and how far out I need to go to cover everything properly. I was thinking about 25-26" inch square would work fine, but I don't know the actual width I've got to work with on top between those rails

[dbhost]

Okay knowing what you are doing.... and wanting to re-cut the holes as needed. Get steel to match the bus roof skin thickness. I think it is 14 ga but not 100% sure.... Trim it to size and weld it in place, prime, and put some sort of paint on it, even temporarily to keep rust away...

[jjhwick119]

Okay, so that's 2 votes for 14 gauge. Thanks yall!