Corrugated Metal Siding – a conundrum
Having read a fair number of articles regarding exterior layers, vapor barriers, thermal breaks, siding, etc.; I am still vexed by how to do my re-siding project with rusted corrugated metal (RCM). I want to use this product because it will provide excellent protection from the elements and requires zero maintenance. And I like the look.
The location is SW Colorado, elevation 7500′, south facing slope, exposed to wind, driven rain, intense sun, and dry air often as low as 5%RH. The house is about 18 yrs old and the channel rustic cedar siding is very damaged. It is cupped, cracked, brittle and scaling. Under the siding (get this!) is chicken wire nailed over 30# felt. (I guess the stucco plan didn’t happen). Under the felt (get this!!!) is 1/2″ sheet rock with OSB at the corners for sway bracing. The Al clad windows have 1-1/4″ face to flange depth.
What I wanted to do was remove the old siding and chicken wire, put on1/2″ blue board as a thermal break then apply the RCM. This would come out flush to the window frame. There would be J-channel at soffit and sides and bottom of windows with air flow gap, and the bottom open with screen. The major problem with this is the sheet rock. I would have to find studs for the roofing screws.
Now I am considering the pros and cons of leaving the siding on, just removing the trim boards and screwing the RCM directly to the cedar or housewrap the cedar first. Or is this a bad idea altogether??
Suggestion are appreciated.
Replies
1/2"
seems awfully stingy on the exterior foam, although I understand it will keep the metal more-or-less flush with your windows. I would consider pulling the windows, installing much thicker foam, and reinstalling the windows over the foam. I would also read up on exterior foam applications and the recommended thickness for your climate. You probably need more than 1/2" to keep the sheathing above the dewpoint.
Are you sure the conundrum board will approve using corrugated metal?
Are you sure the conundrum board will approve using corrugated metal?
much less the rusted part?
conundrum
Couldn't care less what the board thinks about corrugated metal or rust. Thanks for checking.
I agree with David.
The foamboard seems a little thin.
If you decide to go ahead with your plan use a wrinkle wrap house wrap like Tyvek stucco wrap under the foamboard and over the current sheathing board. Typar may also make a similar product. The wrinkle nature of the wrap provides a drainage plane under the foam if you tape and flash it correctly, After the foam board is installed you should also tape all joints with Vycor foam sealing tape. This step will provide your primary drainage plane behind the RCM.
One note of caution. J-channel and metal trim made for any metal siding is not intented to replace flashing. Use products like Vycor tape and Tyveck flashing tape liberally wherever you are unable to install regular metal flashing.