Stop condensation-dripping under shop lean-to

[BJett]

Shop is 30x50 with attached 12ft lean-to with concrete floor. Metal roof condensation under the lean-to is really bad. Literally like its raining underneath. Other than spray foam, any suggestions on repair, prevention, retrofit.

Anyone ever heard of or used Anvil paints "STOP THE DRIP ACRYLIC SEALER"? Says it's supposed to stop condensation when used under metal carports, but couldn't find any user reviews. Thanks in advance for all help-advice

 

[HOTFR8]

You need an insulation foil to stop that happening.

Here it is fitted with wire then the insulation and the metal roof on the top.

 

[BJett]

I was thinking I might could use something like that but wasn't sure. Is that the bubble foil wrap? My concern was since the facing is metal foil, won't I just have the same problem. I know they have some with a white facing. I was hoping to do this without having to R&R the metal roof panels. Thanks

 

[volleyball]

Foam boards will work. The foil would be better if access for large panels is tough.
Heck plastic sheets spaced away from the metal will help, less condensation and what does drip falls on the plastic and you only have runoff at the low side.

 

[larry_g]

Warm moist air hitting cold steel = condensation. I'll bet you roof is shaded from the sun when this is happening. Any way to remove the shade and allow the sun to hit the roof? Otherwise your going to have to install a barrier on the underside. Is removing the metal roof possible and putting some sheathing down and re installing the metal?

lg
no neat sig line

 

[HOTFR8]

I was thinking I might could use something like that but wasn't sure. Is that the bubble foil wrap? My concern was since the facing is metal foil, won't I just have the same problem. I know they have some with a white facing. I was hoping to do this without having to R&R the metal roof panels. Thanks

No it is not a bubble wrap. It should have been installed when the place was built. To fit it now will not be easy.

 

[volleyball]

We call it bubble wrap insulation. Many brands are 2 layers of bubbles with silver foil on the outsides.

 

[HOTFR8]

We call it bubble wrap insulation. Many brands are 2 layers of bubbles with silver foil on the outsides.

Here it is just called insulation foil.

 

[JeremiahTRD]

None of that **** will work. You need Closed Cell Spray Foam Period.
Its the only product that will bond completely to the metal and give a continuous air barrier. It goes on as a liquid and expands into and under the rafters and any ridges in the metal. It won't take much depending on your climate zone an inch maybe two.

The other products will help to some degree but anywhere there are seams or breaks you will still have drips etc... The seams will still allow the air to get above and the metal will still sweat. In some cases it can make the situation worse because the condensation gets trapped. I've seen every attempt out there to fix it and they all fail. Some products work better than others but nothing can touch what foam will do.

That being said Closed Cell will be quite expensive but well worth it.

There are some DIY spray foam kits that come in propane sized tanks, but for that size project just hire a professional it will be cheaper to have them do it than what the kits would cost you.

 

[HOTFR8]

None of that **** will work.

The foil has worked here and my building has been up since 1999. Roof on my extension was done the same way and condensation has never been an issue.

 

[volleyball]

I am a big closed cell fan myself but it is expensive and not going to make that big a difference. Now if you want to condition the space, foam and then the required covering may be worth it.

 

[jlmoss]

I have had the same problem with porch coves and lean-to's. I found if I can put decking under the metal roof, it would stop the condensation. I used either chip board or plywood decking.