Caulking - remove old first?

[Teamfour]

I need to re-caulk all the seams on my Hemisphere. Should I dig out the old caulk first or just put a thin film of new caulk over the old.

[Thurman]

I believe that you could get as many answers as there are viewers to this question. Me, myself--I would remove as much of the old caulk/sealant as possible. You didn't indicate where this old caulk is, such as around a window or door, or just what. The picture does not show what you are working on to me. So, IF it were to be a window or door, I would remove as much of the old caulk as possible, clean the area well with denatured alcohol, clean well with a rag using hot water with just a little soap, wipe well with plain hot water, allow to dry, and use Lexel sealant.

[rsdata]

Remove any caulk that is loose, but I would not work hard to dig it out. If doing roof seams, I would use Eternabond tape and just tape over the old caulk and forget about the entire roof for 10 years.

https://youtu.be/XRy2RbFL_zM

https://www.eternabond.com/RoofSeal-p/rv-rs.htm

[Teamfour]

Originally Posted by Thurman

I believe that you could get as many answers as there are viewers to this question. Me, myself--I would remove as much of the old caulk/sealant as possible. You didn't indicate where this old caulk is, such as around a window or door, or just what.

Sorry, this happens to be along the trim where the front cap joins the side wall. But I need to do doors and windows as well. I have never experienced leaks so I’m leery to disturb the seal.

[007matman]

Would you paint over old peeling paint?

If the caulk is old and cracking, putting new caulk over the top might help with appearance but it's going to continue to crack and release from the surface.

Better to remove first. A heat gun makes it much easier.

[ChrisParise]

007matman,

Have noticed heat gun being advised to soften and remove caulk not just by you but others. Maybe using a heat gun works on housing structures which dont melt, but what RV surfaces do you have experience with using a heat gun?

My MH has a gel coated fiberglass exterior and an EPDM rubber roof with plastic trim - not materials where a heat gun should be used. I could see using a hair dryer in cooler weather but even then I'd be careful.

I use nothing but Proflex RV by Geocel on the exterior.

Chris

Originally Posted by 007matman

Would you paint over old peeling paint?

If the caulk is old and cracking, putting new caulk over the top might help with appearance but it's going to continue to crack and release from the surface.

Better to remove first. A heat gun makes it much easier.

[rsdata]

Maybe using a heat gun works on housing structures which dont melt, but what RV surfaces do you have experience with using a heat gun?

Heat guns usually have two heat settings and multiple ways of using them with specialty tips that may spread out the directed heat. A heat gun applied judiciously works on all surfaces, even delicate ones. You may want to use a hair dryer, but I will use my heat gun and leave the hair drier in the bathroom.

[CincyGus]

Most manufactures utilize Dicor self leveling on roofs and horizontal spaces and Dicor Non-Sag on vertical spaces (Windows, doors, vertical trim, marker lights, etc.).

I'm a proponent of using eternabond tape on roof seams before they start cracking or after removing cracked sealant, reapplying a fresh coat of sealant and letting it set for a few weeks and then applying eternabond tape. Roof edges, AC trim, roof vent trim, etc, everything on the roof. If you prep well and have a clean starting point, using proper application technics, your good for a LONG TIME other than spot checking a few times a year and cleaning it. Leaks kill campers integrity and preventing them is the best thing you can do to make sure you get a good return when you sell it or a long life out of it if you don't.

One last comment is I try to stay away from Silicone based sealants externally. while they seal wonderfully, when you have to reseal, even removing them as much as possible, silicone doesn't want to stick to itself when being reapplied. In fact I've not found anything that will stick to it well so if it starts off silicone and starts leaking, it's basically remove it, wire wheel it to get down to the base structure and then reapply which increases the change of damaging the gelcoat IMO.

[Thurman]

I'd like to clarify my heat gun usage. I had a heat gun with adjustable heat settings. It's a rotary dial type setting. On #1 you can hold your hand at the end of the nozzle and it will never get to warm for you. But--IF you turn it to #20 I guarantee you that it will peel the paint off of house trim or an army tank. So, I try to be careful with my settings so as not to damage any type of heat sensitive surface.

[Mike223]

Originally Posted by rsdata

Remove any caulk that is loose, but I would not work hard to dig it out. If doing roof seams, I would use Eternabond tape and just tape over the old caulk and forget about the entire roof for 10 years.

https://youtu.be/XRy2RbFL_zM

https://www.eternabond.com/RoofSeal-p/rv-rs.htm

What I just did to my TT. Covered all the Dicor with Enterabond tape.
Mike

[dbledan]

Originally Posted by CincyGus

Most manufactures utilize Dicor self leveling on roofs and horizontal spaces and Dicor Non-Sag on vertical spaces (Windows, doors, vertical trim, marker lights, etc.).

I'm a proponent of using eternabond tape on roof seams before they start cracking or after removing cracked sealant, reapplying a fresh coat of sealant and letting it set for a few weeks and then applying eternabond tape. Roof edges, AC trim, roof vent trim, etc, everything on the roof. If you prep well and have a clean starting point, using proper application technics, your good for a LONG TIME other than spot checking a few times a year and cleaning it. Leaks kill campers integrity and preventing them is the best thing you can do to make sure you get a good return when you sell it or a long life out of it if you don't.

One last comment is I try to stay away from Silicone based sealants externally. while they seal wonderfully, when you have to reseal, even removing them as much as possible, silicone doesn't want to stick to itself when being reapplied. In fact I've not found anything that will stick to it well so if it starts off silicone and starts leaking, it's basically remove it, wire wheel it to get down to the base structure and then reapply which increases the change of damaging the gelcoat IMO.

I found one thing that sticks to silicone.....dirt. :-(

[ChrisParise]

Thanks for the clarification. Everyone is used to doing things their way. I do wonder if a newbie might take things too literally and your clarification is very helpful.

Chris

Originally Posted by Thurman

I'd like to clarify my heat gun usage. I had a heat gun with adjustable heat settings. It's a rotary dial type setting. On #1 you can hold your hand at the end of the nozzle and it will never get to warm for you. But--IF you turn it to #20 I guarantee you that it will peel the paint off of house trim or an army tank. So, I try to be careful with my settings so as not to damage any type of heat sensitive surface.

[ChrisParise]

Good products and endorsements.

I use Geocel Proflex RV for vertical surfaces. It will stick to itself and is easy to remove usually coming off in long strips.

As far as flat surfaces where self leveling is needed I like the Dicor products and used them one time so far on an all over touch up on my EPDM roof. Worked beautifully, as I remember it 2 - 3 days to do. Day 1 remove Maxx Air vent covers, wash and let dry using a quality rv roof cleaner. Day 2 clean seams with mineral spirits being careful not to get the EPDM wet, cleaning from front to back if time, start applying self leveling to cracks, pits, holes. Day 3 finish applying self leveling and reinstall Maxx Air covers.

I didn't notice any cracks, pitting, or holes in my factory self leveling caulking until its 8th year of life in the fall. The first decent weather of year 9 I touched it up. That was 4 years ago and it looks factory fresh.

I find it pays to be vigilant looking out for leaks. Last year I found leaks emanating from the flat surfaces on top of my slideouts, areas you normally cant get to under the toppers. That was year 13 of its life. Took a little detective work to figure out but it wasn't rocket science. Ended up replacing my toppers at the same time. Not surprisingly both slide top leaks occured in the same season and it makes when you consider these areas haven't seen maintenance since manufacture.

Good idea on the Eterna bond. I found a different use for it. My arctic pack tank heater pads were starting to lose their adhesion after about year 6. I cleaned the areas around the pads with rubbing alcohol and used the tape around the edges of the pad as needed and as of today after about 7 years they're holding up perfectly.

Chris

Originally Posted by CincyGus

Most manufactures utilize Dicor self leveling on roofs and horizontal spaces and Dicor Non-Sag on vertical spaces (Windows, doors, vertical trim, marker lights, etc.).

I'm a proponent of using eternabond tape on roof seams before they start cracking or after removing cracked sealant, reapplying a fresh coat of sealant and letting it set for a few weeks and then applying eternabond tape. Roof edges, AC trim, roof vent trim, etc, everything on the roof. If you prep well and have a clean starting point, using proper application technics, your good for a LONG TIME other than spot checking a few times a year and cleaning it. Leaks kill campers integrity and preventing them is the best thing you can do to make sure you get a good return when you sell it or a long life out of it if you don't.

One last comment is I try to stay away from Silicone based sealants externally. while they seal wonderfully, when you have to reseal, even removing them as much as possible, silicone doesn't want to stick to itself when being reapplied. In fact I've not found anything that will stick to it well so if it starts off silicone and starts leaking, it's basically remove it, wire wheel it to get down to the base structure and then reapply which increases the change of damaging the gelcoat IMO.