OT (kinda) - Hardi Panel Siding w/o sheeting

[Leon]

No, I meant to say that there was NO tar paper, I only used Tyvek. Given a choice of which one to use I chose Tyvek over tar paper. The layers are studs, Tyvek, then siding.

[Leon]

Interestingly in the last 6 or so years, no ovbious signs of bugs in the store room.

[Markem]

No strength in tension if you mount Hardi panel with out backing it is real easy to break. Would not do Hardi panel without plywood under it. Your friend might just lean right on through it.

Mark

[Swingman]

The idea has been around for years. A similar method sometimes call a "rain skin" has been used in more Northern climates for sometime and this is basically and adaptation of that, but with venting into attics equipped with ridge vents to move the air.

A very simple concept, and one that uses nature alone to provide the benefit ... no moving parts or fuel costs. ;)

You won't find much about skin vent construcion, or literature on it. It is not something usually seen in the industry, therefore most have never heard of it, and like all things unknown, will not embrace it unless someone else does it first and leads the way

Architects are familiar with the principles behind it, and one of the most notable architect/builders in this area has also been building this way for years.

It makes a world of sense in certain climates if you think about it. After all, the siding on a house is non structural in nature, can be thought of as simply as skin protecting the structure from the elements, so why not incorporate air flow, by use of a void space between the siding and sheathing in that protection, allowing quick drying of any moisture intrusion, something which is likely in hot, humid climates that are subjected to periodic high winds and rain.

It doesn't take a rocket surgery mentality to realize the benefits, just some thinking outside the normal. Most builders are deadly afraid to do anything that is not traditional, or that adds cost.

In this case, the cost is minnimal ... the 1x4 stock being the only real cost. Labor to do it is no more than what the normal siding/cornice crew would charge, so you shouldn't see an increase in labor costs at all. Your painter might charge a bit more for filling nail holes due to my own penchant to not blind nailing, but I've never noticed a difference in a painters overall bid because of that.

What's few hundred bucks for a correspondingly bigger bang for those bucks.

That said, it is money spent where the average home buyer can't see it ... an anathema to 99% of builders.

Going on over ten years and no known problems thus far. I did my own home this way, FIRST. You gotta eat your own dog food.

I've never seen abnormal movement with nailing Hardi siding to 1x4's @

16" OC ... AAMOF, probably less ... although I have no statistical evidence to back it up, visually there have been no issues that I'm aware of.

That said, this works very well in the "hot, humid" building zone along the Gulf Coast, and I have absolutely no experience using it in drier building zones.

[nailshooter41]

• SNIP *

THANKS for the great instruction and the time to type it out, Karl. I really like that detail. A lot.

Robert

[nailshooter41]

WOOF!

I like it! Somehow, I would expect nothing less from you. The more I think about this detail the more I like it.

SNIP

I went to a couple of free seminars years ago that Southwest Research put on for our builder's association that concerned airflow and its relation to cooling and heating a house.

They were very keen on air movement, regardless of the climate, unless of course looking at extremes. (For example, the same insulative processes wouldn't be used in Anchorage as Arizona).\

It was the same idea that got me onto ridge vent on houses almost 20 years ago. Yours truly was one (if not the first) to start putting ridge venting on houses.

The sold me by showing me a video from an independent lab of two small, one room buildings of about 250 sq ft. with conventional turbines (2) on one and continuous ridge vent installed on the other.

They set of a mil spec pink smoke bomb in the attic to test the air flow.

The attic space (eyeballed about a 5/12) was timed to see how long it took the smoke to be completely exchanged with clean, fresh air from outside.

The turbine roof took over two hours! The roof with the ridge vent took just a little over twenty minutes to clear the smoke. The amount of heat that was whisked away was incredible. I was so impressed that I contacted Owens Corning and they sent me copies of the VHS tape that I saw and I used them as sales tools.

I certainly don't see how a continuous air flow powered by mother nature's heat would work any differently on your siding detail than on a roof/attic detail. It is the same exact principle, so I would expect the same results. Good results.

Thanks for taking the time to type all that out, and the good explanation that came with it.

*thumbsup*

Robert

[RicodJour]

An attic always has more heat gain, even if shaded by trees, than siding on the North side of the building, so the temperature differential and the chimney effect is greatly reduced.

The eave/ridge vents are there to remove heat, and to some degree, moisture. Rain screen design is meant to reduce moisture, and has an added benefit of reducing heat gain, but heat gain is not always a bad thing - at least not in all climates. I want all the heat gain I can get in winter.

R

[Swingman]

You're most welcome, Robert ... just a minuscule installment payback on the spraying advice!