Drip stop condensation controller technology

Roger Solberg
2/21/2013
I Have seen recent ads promoting a felt membrane attached to the underside of a roof panel that controls condensation by absorbing interior moisture until conditions drop back below dew point, then releases moisture back into air as normal humidity. (Used in post frame buildings over 2x4 roof purlins.)Nice concept, but what about holding water against the bottom side of the roof panel when that panel is penetrated by the roof screws? Any thoughts on long term corrosion around those screws where the galvanizing has been penetrated?.....Is anyone aware of any long term installation history showing no ill effects or accelerated corrosion at the connector penetrations due to holding moisture against the steel?......or am I over thinking this? (The product is also promoted as extra steel protection in corrosive environments such as animal confinement.) Thanks.pl
Todd Miller
Classic Products, Inc.
2/22/2013
The products like this that I have seen do not have 100% coverage so I do not feel they would hold and trap condensation.
David Stermer
2/22/2013
Roger, Thanks for the question! Just to be forthright, Metal Sales, the company I work for, markets this product. My understanding is that there is limited corrosion potential at the fasteners because the backer membrane that adheres the fleece to the metal panel acts as a moisture barrier. I am seeking additional info to confirm this. Concerning coverage, the metal panels can be produced with minimal gaps in the fleece that would expose the underside of the metal to the interior of the building. Regards, David Stermer
Roger Solberg
3/1/2013
David, Did you find any additional information to confirm that these dripstop type products, when attached with screws that penetrate the steel galvanizing ( and the backer membrane referred to) do not increase the potential for corrosion at the screw penetrations? Is there any testing or past history of installation confirming that fact? Thank you.
David Stermer
3/4/2013
Roger, I did have a converrsation with the felt supplier and his response was that they have not had an issue with panel corrosion at the fastener. The membrane tends to protect the panel from internal moisture. I do not have documentation yet, but will have information sent to you. Regards, David Stermer
Guest User
12/6/2014
Hello. I have bought an older home with a hip roof. It is approximately a 5/12 pitch. There is a new metal roof installed. The metal is considered an r panel. The sheets have 1.5" ribs. The metal is laid on either perlins or old wide planks. In between the rafters is r19 faced insulation. Currently it is faced with the paper toward the metal roof. There is condensation building up on the metal. I should add there is blown in insulation in between the ceiling joists. There is an air handler in the attic. Should I take the insulation out of the rafters and lay it over the blown in insulation? Or should I try another kind off vapor retarder.
Todd Miller
Classic Products, Inc.
12/7/2014
Avoiding condensation requires three things: Insulation, Ventilation, and a Vapor Barrier. In some cases, you can "get by" with just two of the three and avoid problems. However, because you do not have decking beneath the metal I think you need all three. I am not sure there is an easy or quick fix to your situation. I am very sorry,
Info @windowsonwashington.net
An informed customer is our best customer.
12/9/2014
Pete, If the attic is vented you need to do some more air sealing and insulation. Combine those efforts with sealing up the ductwork and you should be fine.
Guest User
2/15/2017
I purchased dripstop metal roof sheeting and used it to converting a garage into a insulated office. However I am experiencing problems with condensation and wondered if you could advise me. The building is concrete block and I have installed insulated plasterboard inside and has insulated the concrete floor. The roof is an 8 degrees mono pitch and the roof sheeting's are fixed directly to the wooden purlins with 25mm air gap between roof sheets and insulation. There is ventilation from ridge to soffit. After a cold night moisture appears on the wooden purlins. Do you think - if I need to lift the roof to create a larger gap for ventilation or do I need to consider a different approach ie: underlayment?
Todd Miller
Classic Products, Inc.
2/15/2017
So, there is no wood decking, correct? The metal is on purlins running horizontally. So, you have intake vents at the bottom and clear air flow unimpeded by the purlin to a ridge vent at the top, correct? Is there any way to add a vapor barrier behind the plasterboard?
Guest User
2/15/2017
Thanks for your reply. There is no wood decking and the metal is on the purlins running horizontally. I do have intake vents at the bottom and is uninterrupted from top to bottom. The only way I could get a vapor barrier on is on top of the insulation which is directly above the plasterboard. Do you think I need more than 25mm air flow?
Guest User
2/15/2017
Thanks for your reply. That is correct, there is no wood decking and the metal is on purlins running horizontally. I have uninterrupted ventilation from soffit to verge. I cannot get a vapor barrier behind the plasterboard. However I could get it above the insulation which is directly above the plasterboard. Should I be considering raising the roof up to get 50mm air flow? The building is only 3 metres wide and 6 metres long from verge to gutter.
Guest User
5/12/2017
As water runs off the edge it wicks up the felt to the top plate and runs down the interior wall. How do I stop this
Todd Miller
Classic Products, Inc.
5/12/2017
Michael, can you post photos of the roof so we understand better what you have?

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