Silicone and other sealants

[sama]

  I prefer "caravan grade" than "marine grade"   All the fancier sikas will outlast most of us here,be it marine,bus,caravan etc! aus.sika.com/en/solutions_products/01/01a008/01a008sa04.html

[atefooterz]

Something to ponder is that while marine is designed so those pesky salt crystals do not grow into the surface, at microscopic level, it may also be formulated to work at lower maximum temperatures, than a caravan would experience.

[tasmillard]

Unless you live in colder climates, like tasmania

[Deleted]

After a lifetime of trying all sorts of things to stop leaks and seal stuff these are my products of choice never again will I EVER use silicone anywhere it is a source of failure I have found the new viscount will be done with HB FULLERS TOOLBOX a polyeurothane product which is both an adhesive AND a sealer www.hbfuller.com.au/products/trade/multi-use/272258231.html and any over seal jobs will be done with LIQUIDFLASH paintable membrane  www.constructionchemicals.com.au/workspace/file/product/liquid-flash-1-18315.pdf 

[tasmillard]

So I have decided to go with the old school butyl mastic cartridge as a sealant. Question is, what brand is good? Currently, Selleys have one that is $12 each online. Is this a good brand and price? I prefer to get 10 cartridges in one purchase if that helps reduce price, not sure. What do others use and where did you buy from?

[tim]

I used Z Bond Ezycaulk and it seemed good to use. In 10-15 years I'll let you know if its any good. I got some from Caravans Plus, but Nubco in Kingston stock it too. 

 caravansplus.com.au/catalog/product_info.php?products_id=204


Tim

[doublechevron]

Aug 25, 2016 14:02:26 GMT 10 tasmillard said:

So I have decided to go with the old school butyl mastic cartridge as a sealant. Question is, what brand is good? Currently, Selleys have one that is $12 each online. Is this a good brand and price? I prefer to get 10 cartridges in one purchase if that helps reduce price, not sure. What do others use and where did you buy from?

Yep.. great stuff for the windows ...

for anything you dont' see yourself pulling back off..  I'd still just use white roof and gutter.  The silicon on the roof seams of my 30 year old caravan is still in very good condition.  Correctly applied silicon seems to be a "forever" fix... IF done right.

seeya,
Shane l.

[tasmillard]

Thanks Tim, but for that price ill go here

Cheers.

[78466noM]

I used both the selleys is a lot softer and as I had run out I needed some in a hurry and wasn't prepared to pay what the asking price was locally ( close to $20 a cartridge ) so ordered the Z Bond Ezycaulk from caravans plus it was here in Sydney very quick. Z Bond Ezycaulk is a lot dryer than the selleys and to me seemed easier to work with but harder to clean up excess. they have been on van for over a month now maybe two and it is hard to pick any difference but for me I know what brand went where.If you were to look at it you probably wouldn't pick it.

have fun and be safe Bruce 

[tasmillard]

Just to add here, my father (Gitano) has contacted a Sika rep and talked about options for sealing the caravan (windows, jrails, seams etc) and the rep stated that all their sika range should be considered as having adhesive properties. So sika may not be the option at all which leaves a butyl type product or gawd auful silicone (to a degree) as non-adhesive sealants if that is what you are after.

[Deleted]

More information on Sikaflex.
I have asked them for a self leveling product suitable to seal the roof seams on the caravan and they recommend Sikaflex 521UV as their only product suitable for that application.
A surface preparation it is required by a cleaning and using Sikaflex 205 activator.

[Warrenk]

Sept 2, 2016 18:16:37 GMT 10 @gitano said:

More information on Sikaflex.
I have asked them for a self leveling product suitable to seal the roof seams on the caravan and they recommend Sikaflex 521UV as their only product suitable for that application.
A surface preparation it is required by a cleaning and using Sikaflex 205 activator.

The self leveling sealant which is ideal for your application is Dicor 502. It doesn't require an activator.

Warren

[Deleted]

Dicor 502-LSW Self Levelling Sealant (Singular) This Self-leveling Sealant is a high solids, gun consistency material designed to be used in conjunction with single-ply EPDM Membrane. It is primarily used to fill voids and joints around vents, pipes or other penetrations through the membrane. the EPDM lap sealant is UV stabilized to prevent deterioration and discoloration. It will not stain or discolor any material to which it is applied.


I do not like to use a membrane

[Warrenk]

Dicor 502 can be used on any surface. As EDPM can react with certain sealants, Dicor developed sealants that did not effect the EDPM  membrane that is used on a large number RV's and house roofing in the US.  Copied from the Dicor web site "Compatible with EPDM and most TPO sheeting, it adheres firmly to aluminum, mortar, wood, vinyl, galvanized metal, fiberglass and concrete."

Warren 

[brettm357]

Would selleys solar flex or parfix poly sealant be any good for the outside edge trim windows and hatch

[doublechevron]

THe silicons will work, but will make removal of windows/hatches almost impossible. The only real option is mastic. Everything else sticks to well. Well that's my opinion either way. If you want a scare, go look how badly most of the aussie caravans are assembled. Every window is stuck in with 10 tubes of silicon .... How the hell you would EVER get them out if needed is beyond me.

The main thing is you MUST "squeeze out" the sealer of choice.  Running a bead of silicon/sealer/whatever around the window will NEVER work

seeya,
Shane L.

[mynewstudio]

Hi guys. When I replaced the corner flashings on my van (angle aluminium), I used Parfix adhesive and sealant. I didn't expect to see hairline cracks appearing in it, after just slightly less than two years! Now I'm wondering if I will have to cut it out and reseal??? So disappointed. Any thoughts/suggestions/feedback?

Edited to add, have decided to pull it out and use Sikaflex Pro. Grrrr

[snoops]

Yes, Sika or another quality poly urethane based product is the best way to go. Will last practically for ever.

[Mustang]

Apr 8, 2019 10:20:20 GMT 10 mynewstudio said:

Hi guys. When I replaced the corner flashings on my van (angle aluminium), I used Parfix adhesive and sealant. I didn't expect to see hairline cracks appearing in it, after just slightly less than two years! Now I'm wondering if I will have to cut it out and reseal??? So disappointed. Any thoughts/suggestions/feedback?

Edited to add, have decided to pull it out and use Sikaflex Pro. Grrrr

Parafix is a cheap alternative brand never intended for the Aussy outdoor extremes. Buy cheap buy twice.
If you use any silicone product, bear in mind it is an adhesive, do you really need an adhesive or a sealer?

Every van I have renovated I use a non silicone product where I need sealing only, that way if the window or strip has to be removed due to accidental damage or whatever, there is little effort required.
 

[melaroony]

Hi Team, new to this forum and caravan renovation. Reading through this thread, which goes back quite a way there are tons of recommendations. I have a 1974 Millard. Tomorrow, I need to seal the roof hatch surrounds, the cross seams on the roof and the trim strips (j-trim?) on the roof as far down as possible tomorrow with the lower sections later in the week. 
Initially, I had purchased Sika 291 especially for the trim. Now, given the price (and the subsequent lack of one kidney) I am deliberating this decision. So my questions are as follows:
Given the timeline in the thread and that some tech has become more, possibly, readily used, I'll ask: 
Should I try a caulking strip for the j trims instead? It's cheaper, and apparently easier to use. Will it be so? Is it as simply as applying a strip or is it requiring a strip on the join and inside the trim?

Should I use self-levelling sealant around the hatch and across the roof seams as that seems (sorry) to make sense. Although my limited viewing on this type of sealant indicates that it repairs or 'boosts' previous sealing jobs. Numerous sealing jobs have been attempted on this van by previous owners so I don't know yet what it will be in terms of preparation and ease or difficulty. 

Prior to using this van it had sat for 20 years, it had leaked but been sealed by the last owner. After towing it home, water appears to have re-entered along a roof seam and run inside to ruin the cupboard over the curved dinette seat. Quite a leak.  Re-examining the roof shows a lot of new 'likely' leaks in the not too distant future. 

Thanks for any advice you can offer.

Tim

[Mustang]

Hi Tim,
The thread of sealants has now become very long & for a newbie confusing.
Two ways of looking at Silicone & Mastic is Silicone is an adhesive, mastic is a sealant only.

Butt joins (applying silicone to a surface) rarely works after the van has been exposed to the sun & movement. Neither does mastic.
To seal a J strip, you need to remove the strip, clean off the old, & apply the mastic/sealant from the inside out.

I only use mastic, the vans I have renovated where silicone has been used are a nightmare to pull apart & clean. (Just my opinion)
On the other hand if silicone is used correctly it will see the van out & do a good job IF APPLIED CORRECTLY. (That is a comprehensive reno)
Only use quality brands like Sikaflex if you use silicone or mastic.

For your roof seams I would suggest a bituminous waterproof tape, it is easier to apply to a dry surface & the width will accommodate the vans movement.
Good Luck, come back to us with any further questions.
Brent

[78466noM]

Jun 9, 2019 20:49:45 GMT 10 melaroony said:

Hi Team, new to this forum and caravan renovation. Reading through this thread, which goes back quite a way there are tons of recommendations. I have a 1974 Millard. Tomorrow, I need to seal the roof hatch surrounds, the cross seams on the roof and the trim strips (j-trim?) on the roof as far down as possible tomorrow with the lower sections later in the week. 
Initially, I had purchased Sika 291 especially for the trim. Now, given the price (and the subsequent lack of one kidney) I am deliberating this decision. So my questions are as follows:
Given the timeline in the thread and that some tech has become more, possibly, readily used, I'll ask: 
Should I try a caulking strip for the j trims instead? It's cheaper, and apparently easier to use. Will it be so? Is it as simply as applying a strip or is it requiring a strip on the join and inside the trim?

Should I use self-levelling sealant around the hatch and across the roof seams as that seems (sorry) to make sense. Although my limited viewing on this type of sealant indicates that it repairs or 'boosts' previous sealing jobs. Numerous sealing jobs have been attempted on this van by previous owners so I don't know yet what it will be in terms of preparation and ease or difficulty. 

Prior to using this van it had sat for 20 years, it had leaked but been sealed by the last owner. After towing it home, water appears to have re-entered along a roof seam and run inside to ruin the cupboard over the curved dinette seat. Quite a leak.  Re-examining the roof shows a lot of new 'likely' leaks in the not too distant future. 

Thanks for any advice you can offer.

Gooday Tim Before you attempt to seal check inside top of cupboards where leak is as most millards as far as I know  have timber running along top of wall frame that the roof is stapled to then j rail screwed to as it has a tenacity to rot then no solid surface to seal roof to. It wouldn't be impossible to replace pieces but very fiddly .I sealed mine with the mastic from caravans plus i used the selleys brand from bunnings but found it too runny and I used the tape around the windows and fridge vent .                                                                                             Two years and no leaks but if I do get one it is a very easy repair as mustang has said.   

[melaroony]

Jun 10, 2019 12:01:42 GMT 10 Mustang said:

Hi Tim,
The thread of sealants has now become very long & for a newbie confusing.
Two ways of looking at Silicone & Mastic is Silicone is an adhesive, mastic is a sealant only.

Butt joins (applying silicone to a surface) rarely works after the van has been exposed to the sun & movement. Neither does mastic.
To seal a J strip, you need to remove the strip, clean off the old, & apply the mastic/sealant from the inside out.

I only use mastic, the vans I have renovated where silicone has been used are a nightmare to pull apart & clean. (Just my opinion)
On the other hand if silicone is used correctly it will see the van out & do a good job IF APPLIED CORRECTLY. (That is a comprehensive reno)
Only use quality brands like Sikaflex if you use silicone or mastic.

For your roof seams I would suggest a bituminous waterproof tape, it is easier to apply to a dry surface & the width will accommodate the vans movement.
Good Luck, come back to us with any further questions.
Brent

Thanks Brent, sorry for the lack of response. I've been up a ladder. I have highlighted a bit in red in your reply. Do you mean by that, applying the sealant with the interior panels off and the cleaned j trim on the outside? In the end we took the trim off and cleaned it entirely, then applied Sikaflex 291 (way too much of it the first time) to the roof join and then to the underside of the trim and then screwed it back down. Clean up was a nightmare! The second trim was cleaner.

I have decided that I am not going to pull the furniture out as it's in great nick, and the roof has come out but the wall panels will stay too and all can be painted. I bought the Decor self-levelling sealant to use on the hatch surround and the cross seams but haven't yet due to the rain so the bituminous waterproof tape is still an option I suppose, but the sealant was expensive and I don't know where to get the tape, as yet!

[melaroony]

Jun 13, 2019 14:34:27 GMT 10 78466noM said:

Jun 9, 2019 20:49:45 GMT 10 melaroony said:

Hi Team, new to this forum and caravan renovation. Reading through this thread, which goes back quite a way there are tons of recommendations. I have a 1974 Millard. Tomorrow, I need to seal the roof hatch surrounds, the cross seams on the roof and the trim strips (j-trim?) on the roof as far down as possible tomorrow with the lower sections later in the week. 
Initially, I had purchased Sika 291 especially for the trim. Now, given the price (and the subsequent lack of one kidney) I am deliberating this decision. So my questions are as follows:
Given the timeline in the thread and that some tech has become more, possibly, readily used, I'll ask: 
Should I try a caulking strip for the j trims instead? It's cheaper, and apparently easier to use. Will it be so? Is it as simply as applying a strip or is it requiring a strip on the join and inside the trim?

Should I use self-levelling sealant around the hatch and across the roof seams as that seems (sorry) to make sense. Although my limited viewing on this type of sealant indicates that it repairs or 'boosts' previous sealing jobs. Numerous sealing jobs have been attempted on this van by previous owners so I don't know yet what it will be in terms of preparation and ease or difficulty. 

Prior to using this van it had sat for 20 years, it had leaked but been sealed by the last owner. After towing it home, water appears to have re-entered along a roof seam and run inside to ruin the cupboard over the curved dinette seat. Quite a leak.  Re-examining the roof shows a lot of new 'likely' leaks in the not too distant future. 

Thanks for any advice you can offer.

Gooday Tim Before you attempt to seal check inside top of cupboards where leak is as most millards as far as I know  have timber running along top of wall frame that the roof is stapled to then j rail screwed to as it has a tenacity to rot then no solid surface to seal roof to. It wouldn't be impossible to replace pieces but very fiddly .I sealed mine with the mastic from caravans plus i used the selleys brand from bunnings but found it too runny and I used the tape around the windows and fridge vent .                                                                                             Two years and no leaks but if I do get one it is a very easy repair as mustang has said.   

Thanks 78466noM, the sealing job we have done seems to have stopped the leak but who knows for how long. The roof hatch is being renewed and sealed and I think with the roof cross seams also it should go some way to helping. Great tip on the windows too thanks.  

[Mustang]

The tape is available at Bunnings.
Clean up is much easier if you use a thin plastic card, run it along the surface to scoop up excess rather than wiping, wiping smears & makes the job from easy to tedious.