I am installing Certainteed 4X8′ Fiber Cement Siding panels on my home. I’ve sheathed the building with 1/2″ structural plywood and will be using Tyvek DrainWrap as the weather resistant barrier.
I have also purchased several rolls of Home Slicker (http://www.homeslicker.com/index.htm) but I am concerned that in addition to being overkill,that with the weight of these panels fastening them 1/4″ off the building will cause problems. Is the Tyvek DrainWrap sufficient?
Certainteed was no help at all. They would not even state a preference for Tyvek or 15# felt. The did say they don’t recommend an airspace but everything I’ve read suggests it’s particularly important when installing fiber-cement. Any advice greatly appreciated.
Here’s a little more information about my project. My home is in Oakland, CA and was built in 1963. We’re replacing all windows, doors and T-111 siding. We’ve made a number of improvements to the existing framing,sheathing (there was none previously) added foundation bolts and closed-cell spray foam insulation.
We’re starting with an small building in back to refine our installation techniques and to make sure it’s right for the house.
Replies
Paul,
I am curious. Where have you read about the importance of an airspace behind fibercement siding? What sort of problems did the airspace solve?
Bill
I see no reason for the RAINSLICKER
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Agreed. tar paper, spline the butts and caulk with "big stretch" man I love that caulk.
I had a catastophic failure of NP-1 urethane caulk ( SWilliams sold it to the HO on my job) and the Big Stretch saved the day.
The NP-1 failed in less than 3 days, it appears that it needs to be a large bead, NFG for slight gap filling.Spheramid Enterprises Architectural Woodworks
"If you want something you've never had, do something you've never done"
3-4 years ago at JLC Live I listened to the lecture by George Tsongas, who has done a lot of lab testing on water intrusion into walls. His results were that a rain screen was most essential behind FC siding, because of the amount of water that it can absorb, IIRC he stated it will absorb ~30% of its weight in water when there is a leak behind the siding. I assume his tests were with FC planks, not sure how the 4x8 panels would fare.
david, """...IIRC he stated it will absorb ~30% of its weight in water when there is a leak behind the siding. """ And if there is no leak? I have been having a difficult time buying into the rain screen model of building. If the primary weather protection is doing it's job then whats the point? If it's not then to me the rain screen is a bandaid approach to an inadequate siding job. I could use some education I guess but it doesn't fly by me right now. I do understand the air space behind siding as a vent skin model of building. No problem there, and I have done it in the past on several commercial projects to control solar gain.
They can't get your Goat if you don't tell them where it is hidden.
I think the evidence is strongly that a rainscreen helps improve paint life and promotes drying of the sheathing. I live in an area with lots of wind-driven rain in the winter and it pushes water into every possible gap. Up in BC it's now code to install siding over a gap.
I do believe in rainscreen ideas. I have done too much demo over the years finding rot where a rainscreen would have prevented it. I also know of several places where moisture in walls cost the inhabitants far too much in repainting wood siding where the old oils had blistered off.
At the very least, wood siding will last longer with rainscreen protection.IIRC, you are in the wst where the residences are only a hundred years old and where the climate is much drier, so rainscreen protection might be less valuable than in this humid high rainfall eastern side of the country.
Think?
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This poster mentioned that he already is going with the wrinkled housewrap so he already has provided a drain path
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I've used that. It's pretty easy to crush it as you nail on the siding, and it doesn't provide the 3/8" gap that is the rec'd minimum.
rain slicker will crush too - certainly not as much...capiallary flow still happens, just not free flow
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Never used rain slicker. There was some discussion on JLC, and apparently you can't nail things as tightly as you normally would, without getting some rippling where the nails suck the siding in.
I've sheathed the building with 1/2" structural plywood
What does the structural mean?
I just redid my house pretty much like you are intending to do. I put a 12" wide piece of tyvec along the bottom. I then installed a piece of Tamlyn Lapstart Starter Strip continuos along the bottom. Celetox recommends something like this to preventing the material from cracking if it is bumped. I then installed Tyvec the rest of the way to the top of the wall and slightly lapped the Lapstart. I then put Rain Slicker on stopping it just before the bumped out edge of the Lapstart which let the sheet rest directly against the vynal strip on the bottom. Read the Rain Slicker instructions. They are picky on how to put it on. I also used Tamlyn Vinyl T Mold between the Sheets at the vertical seams. saves a lot of caulk that Celotex calls for.
Went on well and looks good. Issues I had are as you suspected. If not careful when fastening the material the back breaks out. I used screws and had to predrill and counter sink the holes. Once I did that had no problems.
I think it is a good setup and expect to get a long life out of it.
Jay
Thank you everyone for your help and advice.I've been delayed a few days by rain and as well as some damaged goods in the first delivery. I've decided to use the HomeSlicker in the areas that take the most weather but not in the more sheltered areas. I'm looking forward to employing these techniques.I'll post pictures in a couple weeks. Thanks againPaul
You've probably already considered this so I hope it's not too obvious... you may need to fur out your trim in the areas where the Homeslicker is used - the 3/8" can make a difference and togher with the siding, will offset most of a 1x trim board.