I have been constructing a small outbuilding and it is now framed, wrapped with Typar, and the roof is on with asphalt shingles. I have a My question is about standard methods for siding and the specifics of siding my building in the northern California climate.
1) At the bottom of the building there is a 5/4 piece of trim that is intended to hide the 4×4 PT frame.
2)Collins Truwood lap siding is the material.
3) My understanding is I need to use ZBAR flashing around the bottom of the trip and leave a gap between that flashing and the first row of siding. I believe this is so that no water will wick up into the siding. Some sources say to make sure the ZBAR is covered with the housewrap but others do not mention this.
4) Is it desirable or necessary to use furring strips or rainscreen products such as HouseSlicker between the Typar and the siding? Calling around to the professional building suppliers in my area, they seem unaware of the rainscreen products suggesting they are not usually used. I am not sure that furring strips are used between the siding and sheathing either and maybe that is because of the amount of rain we do not get.
Is there anything else I should be doing to ensure the siding job follows best practices?
Thanks
JR
Replies
Use the flashing, under the housewrap. Furring strips would be cheaper than a rainscreen system, and just because it isn't common practice with builders in your area, doesn't mean it isn't a good idea. It will keep the back of the siding dry and prolong its life.
Thanks for your comments ... after doing some more web searching and FHb searching using the string "rainscreen" I discovered more information. Knowing nothing about this, my simple observation is that the need to evacuate water than can get behind the siding seems important. If the siding is nailed directly to the sheathing (with only the housewrap in between) then I do not see how the water has a clear path out of the structure. In my climate this may be a small issue since the horizontal rain storms are infrequent, but they happen often enough. Understanding the principle of what to do in a variety of climates is useful for me ... who knows, I may move to Montana.My house (built about 1990) has similar siding nailed directly to the sheathing. Having recently replaced some of that siding after installing a new window, it seems that the siding is generally in good shape. That leads me to believe there is less of an apparent problem with this construction technique in this climate. However, it seems there may be some advantages to having some breathing space behind the siding and so the plan is to sort out if furring strips of some rainscreen product such has Homeslicker is useful. Maybe not where I live, maybe so in Montana. Understanding the principle of what to do is as important to me as just getting it done.Thanks,
JR
Having recently replaced some of that siding after installing a new window, it seems that the siding is generally in good shape. That leads me to believe there is less of an apparent problem with this construction technique in this climate.
Possibly true. But also possible is that the side where you dissassembled was less weather beaten than another sides. And the siding from 1900 is likely better material than what is available today.
The rainscreen idea using furring strips would add little to the intial cost, but could reap big dividends in the long haul. View Image
The cost and time of adding furring strips or even the homeslicker type fabric isn't a concern given the size of this building and that I am also using this construction as a learning experience. I guess that in my climate, using furring strips or rainscreen construction is less common that in other places. Still, I don't get how any water can escape when the siding is nailed directly to the sheathing. I can only assume that it is just not much of an issue.Thanks
JR
I don't get how any water can escape when the siding is nailed directly to the sheathing.
It moves down the face of the housewrap/felt until it is forced to the surface at penetration flashings or water tables. Any moisture will move more freely with the rainscreen system in place. View Image
Fir the siding out with vertical strips of #30 felt, 2" wide over each stud.
Easy, cheap and effective method of allowing a small ventilation/drainage cavity between the wrap and back of the siding.
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Thanks, good suggestion on the felt, I will do that!
JR
You are welcome
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#30 felt is not thick enough to provide an adequate rainscreen gap. Tests I've seen all conclude 1/4" min and optimally 3/4". With just #30 there is a good chance your building paper or wrap will be in contact with the back of the siding.
True... but without it, you are certain to have contact.
Make it double thickness of #30 if you want... or triple.
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