I have a question regarding using Z bar in the replacement of some rotten exterior (T-111) siding on a house with a raised foundation. The siding is rotten in a few spots along its bottom few inches Given that the home is about 30 years old, I am told this rot problem is not all that uncommon. I intend to cut away with a circular saw 6 – 12 inches (the precise amount is not yet determined) of the original siding along its bottom edge the entire length of the side of the house. Then I will prime the cut edge of the original siding and slip the longer part of the Z configuration of the “Z bar” behind the original siding, and have the shorter part of the Z configuration in front of the new replacement siding.
My question is how much space, if any, should I allow between the freshly cut edge of the original siding and the narrow horizontal section of the “Z bar” that will be immediately beneath the original siding’s freshly cut edge. For appearance’s sake the less space the better. The repair job would be least conspicuous that way. But I don’t know if I should allow some space (i.e., 1/16″) for subsequent exspansion of the siding, or even more (i.e., 1/4″) to prevent wicking up of the moisture into, and behind, the orginal siding when it rains, and thus once again have rot problems down the road. I am getting different advice from different sources. I just want to know what the acceptable practice is in the field by reputable builders.
The house is located about 10 miles from the coast in central California. So both our winters and summers are mild.
If I do need to leave space either to allow for expansion or prevent the wicking up of moisture, please let me know specifically how much you recommend. And do you see any harm in my helping to conceal this conspicuous gap with paintable latex caulk?
Thanks folks, for any advice you can provide. And if you are actually work in the construction industry I would appreciate it if you would identify yourselves as such.
Replies
T-111 really is a cheap temporary material and not really suited for permanent use in the weather. The rot you found is quite common.
There are others here who can better answer your question. I'd like to suggest that you consider Hardiepanel vertical siding. It will last longer than anything else on your house. http://www.jameshardie.com/homeowner/prodhome/hardipanel.php It won't match the appearance of T-111 closely enough to not look different when placed adjacent to it.
Wayne,
Sorry for the delay in reponding. Thank you for your input.
Tom
A collective thanks to all of you that took the time to respond to my inquiry. I will probably stick with the Z bar as opposed to the "water table' because some sides of the house are not a problem and I want my "fix" to be as close to the original appearance as possible.
What about putting up a piece of azek for a water table as the right coasters call it. This will prevent this rotting problem in the future.
When you cut the siding put a bevel on the bottom of the pieces, 5 degrees.
As for the cut ends they need to be stained or painted after you cut them, this will also help prevent the wicking problem. I'd leave an 1/8" gap between the flashing and the siding. An 8d nail works as a good spacer.
As for caulking that seam, that would trap water between the siding and the flashing making the problem worse farther up the wall.
As for my identity, I act as a carpenter for a living during the day, at night I'm Batman.
I only golf on days that end with a "Y".
T 1-11 is sorry siding but that said there are probably millions of houses sheathed with it. I've made the repair you're referring to many times. We used to use a PT 1X 6 or 8 as needed but now use Azek instead. It makes a nice looking water table and lasts forever.
I just made almost this exact repair on my own house except the siding is just 1/2" MDO plywood. (I'm not a professional.) I pushed the Z-bar up as far as it could go on the existing siding. I did not use caulk, because I thought the conventional wisdom is that caulk does more harm than good in this situation (keeps moisture from getting out). I primed and painted the back of the new wood, and all the edges (including the cut existing wood) before installation. If I had to do it over again, I would have used epoxy sealer (from the Rot Doctor) on everything, but I didn't know about it at the time. The old siding lasted 25 years and the edges were not painted, so I figure the new will last at least that long.
Now, a question: What is a "water table" (I'm on the East Coast but have never heard the term). It sounds like the perfect solution. I was thinking of using Aztek siding, but the existing studs are too far apart to use it without backing.
Water table can mean different things, but I think what is being referred to here is the belt that runs around the house below the siding /finish surface. I think generally at the level of the rim joist, or there abouts. The material varies.
Mike,
The epoxy sealer, Rot Doctor, how does that work in repairing rotten sections of the siding? Are you recommending cutting out the rotten area and then plastering the hole with this stuff? Because the rot goes all the way through the siding, I don't think it would adhere.
Are you recommending cutting out the rotten area and then plastering the hole with this stuff?
No, sorry I was unclear. I was talking about sealing the edges of the new plywood with the epoxy sealer. It's a very thin epoxy that soaks way into the wood, and is advertised to prevent rot for a long long time. What I did instead was prime and paint the back and all the edges with conventional paints. Since the old stuff lasted 20 years with just bare wood, I think my repair will last longer than I will.
Regarding the Z flashing, the T-111 seems to have a greater tendency to expand horizontally more often than vertically. That is the problem I am having and I have the exact same siding and installation.
I would leave a small gap as stated, such as a nail width, and paint the devil out of the edges. The water table effect looks nice if you can make it work.
Whatever you do, don't caulk the bottom or it will rotten sooner than before. Mine is coming off and going to Hardieboard.
Of course what do I know, I'v been a tinknocker for 30 years. But I did stay at a Holiday Inn Express...
I've heard of this problem a lot with T-111, but have also heard that there is a better product, that looks the same, but is made of mohagany, I believe. Ok, not the same, but once its painted you can't tell. It's supposed to be much better, but it is obviously more expensive.
Young, poor, and eager to learn