house deck joint

I have an old steel houseboat I'm beginning to restore.

The worst problem initially is the house to deck joint. It has failed in a couple of places and isn't water tight almost anywhere. Both are 1/8 sheet metal and the deck is turned down to follow the house down an inch or so just like the second picture on this page http://www.efunda.com/processes/metal_processing/welding.cfm. It is spot welded inside along the bottom edge but I can't tell if it was welded or sealed some other way on the top. The PO says he would caulk it from time to time and it was always a problem.

I thought it should be welded from the top to fill in that joint and make it water tight before paint but some one else suggested solder. I'm worried that if there is any flexing the joint will give up. Maybe caulk is best. It's about 70' of joint.

At any rate I would value your opinions on what is the best way to fix this permanently.

 

I guess the benefit of a good caulking compound is the flex, and it seems the cheaper way to go.

Even solder over 70' long is going to have a few flaws - I see caulk as the best solution, but make sure it makes the water run off onto the deck, and not pool against the side.

That would take a heck of a lot of solder to accomplish.

 

Sikaflex.

PDW

 

Sikaflex it shall be.

 

The PO had trouble with sealant - you have a hole that will keep water in contact with the metal - all sealants seem to have problems with this type of joints - getting the surface 100% clean is going to be a problem.

Solder does not sound like a good thing to even think about - the amount of heat for 1/8 inch metal would be too large.

I would think strongly about the welding - the hole could be filled and a fillet weld done so the water would drain away from the wall - weld prep would be important - welding over rust, paint and old sealant is not a good plan -

 

Looks like you have the same boat I do and a similar issue. I am planning on using sikaflex when I haul the boat shortly.