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Way OT: Stopping leaks in a greenhouse roof.

crossthread

crossthread

Titanium
Joined
Aug 5, 2004
Location
Richmond,VA,USA
I built my wife a greenhouse about twenty years ago and the roof has started to leak at the seams. You might say "so what" but it fills up the trays with water and drowns her seedlings. I have tried doing everything I can from the inside using silicone and some exotic expensive sealers. What I plan on doing is renting a cherry picker and sealing the joints from up top where it should be done. Removing the panes is not an option. The "panes" are from tempered sliding glass doors where the seal went bad and they fogged up. I got them basically for free by contacting folks who replace them. They are glad to give them away. I just separated the rubber seal with a utility knife and cleaned them up. I am asking here because I can't find what I need and you guys are kind of material wizards. I am looking for something I can cover the joints with after applying a heavy bead of sealer. I am envisioning something like those guards that go over cables run on the floor. About three inches wide and coped out at the bottom to allow for the bead. The coping is not needed if the stuff is flexible enough. They don't have to be sticky as I plan on setting them in sealer. One of the problems is that I need a crapload of the stuff so it needs to be fairly reasonable in cost. I can't seem to be able to find any tape, or rolls of anything that I could squish down into the sealer to protect it somewhat from weathering. It doesn't have to be clear. Something .020" or a little more would be nice. Any ideas? Thanks very much.
 
The metal roofing repair people have a very sticky tape with IIRC metal on top
(Heck, it's shiny for all I know)

Lowes and HD had it, maybe for gutter repair as well.

The camper people have some stuff too.
 
I used to manage a large nursery operation. We had 2 glass houses. Bossman sent me and a buddy on top with foam spay insulation " great stuff" from Lowes. We actually had 2 55 gallon drums of the commercial stuff. It works if you can get on top. Clear silicon would probably be neater on a small house!
 
For the sealing from top, you want something that is very U/V stable, or it will break down and you will be back to the same place. Not all the silicone is good for outdoor exposure.

Also, it may make a significant difference exactly how the panels are held. Can you explain what the existing construction and sealing is?

And how BIG the thing is?

You say "removing" the panes is not an option..... is "raising them" a bit, done from the inside, also not an option? If they were laid on the frame with sealant in between, you might be able to raise, scrape, re-apply the sealant, and lower again.

Also, have you determined WHERE the leak is? If you have sealed from inside, without results, you may not be attacking the real problem.
 
JST to answer your question the greenhouse is 14 x 30. It was originally constructed by cutting rabbits in the 2 X 6s and laying the panes in a bed of 100% silicone. This worked very well but it is now time to redo something. There are a few that may be able to be lifted slightly and resealed but the majority will need something from the top.
 
Never bed glass in silicone on wood, never works long term, far far better to sit it on EPDM foam tape, everything can move yet remain sealed, use high expansion foam tape were you need it like joining wood to a masonary wall and it just plane lasts forever works and has none of the fucking mess of silicone snot!
 
Two things. First: You should treat your glass panels as shingles, with an overlap so water will run off. Re-engineer if necessary.
Second: Google up Eternabond RV/roofing repair tape. It's butyl rubber on a UV stable plastic backer, thick but flexible and up to 6" or more wide, 50+ foot rolls available. Clean the surface very, very well first, and you have to spec a width that will get beyond the footprint of the former silicone.

Chip
 
Silicones were/are advertised as adhesives, but not for wood. As the wood ages and moves, the bond is easily broken. Adama has it right with the EPDM foam in that EPDM is UV resistant and does not age like other elastomers. Unfortunately, to redo the roof with new sealants will just about mean redoing the entire roof.

Is there exposed wood between the glass panels and at the top? If so, you could apply a strip of aluminum coated on the underside with EPDM that would bridge the gap between the glass and the wood.

Tom
 
Butyl glazing tape to bed the panes, but you will have to remove them an clean both the pane and the rebate.

Old greenhouse glass was bedded in oil putty or sometimes a lead capped glazing bar.

Silicone is your problem here.
 
Eternabond will do the trick but it is expensive and will need the class to be acetone clean.

A better option would be to lift out from bottom then scrape out the wood to clean it up then seek out and use proper sealer which could be simple latex paint but that depends on condition of wood.

Once that is done look at self leveling dicor which another rv product or seek out assistance from a good window company that builds wood frame windows to confirm current product.

Main issue is the wood must be clean and properly sealed.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk
 
To be fair, 20 years of good performance is hard to argue with. But the construction method was not necessarily well chosen when it comes to easy repair.

I'm not too sure I like the foam tape, either, at least from a repair point of view. At this point it may be a real job to put in tape.

If the wide butyl stuff can be stuck on OVER the glass and frame, on the outside, it might be a good solution. Goes right from pane to pane, and should keep out all water. Being on the outside, it would be pretty repairable as well, although you would need a lift.

Old time putty worked pretty well, and they had a lot more panes, all much smaller, so a lot more linear feet of joint. Judging by what it took to re-putty windows on our 80 year old house. That putty can stick tight when applied right. I doubt it would have leaked at all in just 20 years, even on metal. When the steel basement windows were replaced with glass block here, the glass was still tightly sealed. They were original.
 
Thanks very much for all the replies. As I said in my first post, removing the glass is not an option. I bought a case of something called Lexel on line that was recommended by a roofer. He also said using silicone is just wasting time and money. I still want to cover whatever I put on from the top. Someone asked if there was a gap between the panes and yes there is, about a half inch. I could cut some strips of something and attach them over the joints for further protection. At first I was thinking of salt treated lumber cut into strips and nailed down with copper nails. I am afraid to use a screw gun because any misalignment and there goes the glass. This is of course tempered and although it is amazingly strong, all you have to do is nick it and it explodes. The problem with salt treated strips is that they are so unstable. I actually used strips on the front wall really just for cosmetic reasons and some of those strips twisted like a snake, however most of them are still fine. Easy to replace a few on the walls but a real bitch on the roof. I may be able to use EPDM strips about two inches wide and then cover that with something for further protection. Thanks again for your input.
 
EPDM is UV stable. I've had some exposed to the sun and weather for 21 years, and it is still fine.

I suppose you could do something for mechanical protection, but I am not sure how you would attach it.
 
Interesting stuff Chester. If I live long enough to build another one I would consider that. Any type of cap that I put over whatever I use ( ain't going to be silicone I can assure you) would have to be attached carefully. I was thinking about copper nails for two reasons. One I have a bunch left over from my boat building days and two I can easily feel the difference between wood and glass. I would pre-drill the slats (or whatever) and stick the nails through the center. I could then hit that 1/2" gap between the panes fairly easily and feel that I am in wood not glass. I would then carefully tap them home. The best thing I have learned from you guys is that EPDM is the way to go. I am now searching for rolls of the stuff about 3" wide. Thanks again.
 
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