welded aluminum cabin roof construction

[777]

I'm chasing down a leaking roof (appears to be simply poor caulking) on a welded aluminum boat, and it seems the roof sheets are just spot welded and rely on sikaflex for any waterproofing. does anyone know why that is? would it be feasible to have the seams welded from only the top, or would it require removal of everything below?

777

 

[trophywife]

if it has any kind of headliner than yes, full peel back and re -glue after.

would it not be easier to clean and re-caulk it?

 

[777]

if it has any kind of headliner than yes, full peel back and re -glue after.

would it not be easier to clean and re-caulk it?

yes, that's what I'm going to do. It just seems odd to me that the rest of the boat is welded (obviously) water tight, but the roof seams appear to be just spot welded and sealed. I was wondering if there was a reason for this, and if it's common.

 

[ReelSlim]

Time and money when it was built would be my answer. It's unfortunate really when you think about a few more welds and never have to worry about it again. After a well welded bottom I would think the roof would be high on the list of things to make watertight on a boat? lol I would be curious to know how its supported underneath and how much it flexes and possibly causing the sealant to fail.

 

[Corey_lax]

Can you put a strip of aluminum down overtop of the joint and set it into a bed of sealant? That would probably be the easiest solution that will seal it and if it’s hidden from line of sight, it should be fine

 

[Corey_lax]

I would think that a boat hard top flexes quite a bit when pounding through waves. Maybe they were looking to put the flexible spot at the top instead of stressing the more important welds

 

[profisher]

Bad place for sealants as UV from the sun is going to break it down repeatedly. So just like an RV roof you will be chasing it every few years to keep it from leaking.

 

[Chasin' Dreams]

If you're going to have it welded from the top you will have to be careful with the heat up of the metal with any fabric/headliner material underneath it. As well as any wiring that may be running under the headliner etc. I feel the same as the others; if a builder is going to put all that labor time, money into building a welded aluminum boat then the roof should be completely welded too IMO. But the roof is a fairly common place for builders to do what you are seeing in your boat unfortunately. If you are going to have any of the seems welded where there has been Sikoflex used you will have to completely remove that from the metal before attempting to weld it. Needs to be properly cleaned bare metal to metal seem for the Mig or Tig weld to be done right. Even if you weld from the top but there is Sikoflex on the underside of the seem it still will mess up the weld.

 

[halimark]

I would clean, remove headliner, electrical and all, properly clean and weld, add supports or brackets to stop/reduce flex. I cant even imagine this on a welded boat. I used 1 piece of aluminum for the roof hardtop on my fiberglass DE, water dripping in the cabin at anytime is horrible. What is the brand of your boat. Need to know what one NOT to waste $$$$ on. What else was done the cheapest route??

HM

 

[ryanb]

Interesting choice for the builder. Makes one wonder if they tack welded it in place and forgot to finish the weld later on. By the time they discovered their mistake the wiring and headliner (and possibly paint) had already been added and it was too late and they just used sealant to finnish it off instead. What brand boat is it if you don't mind saying?

 

[777]

The boat is a Lifetimer from the late 1990's. i actually had the chance to speak with the owners son, who was very gracious with his time and friendly. He said that they sikaflexed them because it wasn't feasible to weld the thin roof material for a single long weld. he said the material would pull and bunch up. I'm not sure that makes sense to me if other boasts using the same material have welded seams on the roof.

 

[ReelSlim]

The boat is a Lifetimer from the late 1990's. i actually had the chance to speak with the owners son, who was very gracious with his time and friendly. He said that they sikaflexed them because it wasn't feasible to weld the thin roof material for a single long weld. he said the material would pull and bunch up. I'm not sure that makes sense to me if other boasts using the same material have welded seams on the roof.

In all honesty what is he going to say....lol They may have changed the way the do the roofs now but maybe not. If the material is that thin than perhaps going thicker would be a fix? Or what is usually done on long welds is multiple shorter welds that overlap allowing the material to cool and not deform as much. Just going by my recent experience on my build and not trying to shoot the messenger...lol I know before I pulled the trigger on getting one built there was one builder that went silent after I simply asked a question as to how something was going to be done in the quote. It all worked out for the best in the end....I was fortunate enough to get a lot of photos along the course of the build and I was impressed with the strength of the roof and full welds. Like I say I think a lot of builders do things differently over the years from learning stuff along the way and others just are about costs.....Let us know how the fix turns out.

 

[alumaman]

The boat is a Lifetimer from the late 1990's. i actually had the chance to speak with the owners son, who was very gracious with his time and friendly. He said that they sikaflexed them because it wasn't feasible to weld the thin roof material for a single long weld. he said the material would pull and bunch up. I'm not sure that makes sense to me if other boasts using the same material have welded seams on the roof.

I had lifetimer with spot welds on the roof. It did leak so I removed the old caulking and re caulked with sicaflex. The problem spot was the port side rear of the roof. There are drain holes but they are small dia and would plug with debris. Another trouble spot was where the cabin meets the hull which was spot welded and caulked. The caulking broke down so same thing, I removed the caulk and re caulked with sicaflex. My boat was built in the late 80's.

 

[bullyjack]

Back then the welding machines didn’t have the teknolegy they do now. Now with being able to adjust ac balance, cleaning, pulse its alot easeyier to weld thinner material without distorting.