Frequently Asked Questions
With the vent is installed between the concrete foundation and the sill plate, it supports the entire weight of the house. Will it crush?
No, it will not crush. The vent is made of a composite material that consists of calcium carbonate, polyolefin resin and recycled plastics. It has an ultimate compression strength of over 56,000 pounds per lineal foot of Joto-Vent, and when you apply ICC-ES you can safely support 7,140 pounds per lineal foot of Joto-Vent. Wherever you trust a wooden sill plate, you can trust The Joto-Vent System.
I see the holes in the vent are fairly large. Can bugs get in it?
The Vent is only part 1 of a 2-part system. The holes in the vent are 8.0 mm or 5/16” in the smallest dimension, which is slightly larger than the IBC code states as acceptable. The vent is just the first part of the Joto-Vent System. We also have a custom piece of covering / flashing that is installed over the vent, part 2 of the system, when the exterior siding is installed. This covering has 1/8” holes in it and that is because some building jurisdictions like to see 1/8” holes to keep the bugs out.
Is this a brand-new product on the market? Has it been tested?
The Joto-Vent System has been certified by IAPMO for use in the USA since January 2015, with our UES report and, as of May 2019, our ICC-ES report. Beyond that, it has a more than 45-year track record of successful use in Japan. The Perimeter Vent System is the most common way crawlspaces and foundations are vented in Japan, and the Joto-Vent System has over 60% of the market share. The Joto-Vent System has been successfully installed on more than 5.3 million homes.
Is this a green product?
YES, it is a green product. The Joto-Vent has a recycled plastics content and when used properly you can collect Built Green points for construction projects. Since the vent is installed between the concrete foundation and the wooden sill plate, the plate is not in direct contact with the concrete, so it does not have to be treated lumber. Therefore, when you use the Joto-Vent System you can eliminate all treated sill plates and treated hardware from the job site, giving you more Build Green points for your project.
How many sizes does it come in?
The Vent comes in 2 sizes, 4” wide for 2 x 4 framing and 6” wide for 2 x 6 and 2 x 8 framing. The covering / flashing comes in 1-3/4” (45 mm) depth (protrusions) from the wall in white only. This comes in our Architectural Series 28-gauge galvanized steel and in our Premium Series 17-gauge aluminum.
How does it perform during earthquakes?
This perimeter venting system was invented in Japan, (where they had previously used the same type of vents installed in the concrete as is used in the USA) because during an earthquake, the weak point in the foundation is where the concrete vent box is located. This is why the Joto-Vent system sits on top of the foundation wall and not set into the concrete; to keep the strength of the concrete foundation wall. We have also done shear wall tests to prove that the wall is just as strong with Joto-Vent as it is without the vent. Test data available on request.
Can I use this ventilation system on my current house?
NO, this vent is for new construction or new additions only. It must be installed under the sill plate so it cannot be retrofitted into an existing house.
Can this system be used for only crawlspace ventilation?
NO, it can be used around inside of the garage as well with our special AIR BLOCKING plugs installed in it to prevent air flowing from the garage to the crawlspace. It is added here or in other locations on the foundation wall to keep the sill plate and stud height the same all around the foundation. Also, can be used to separate the sill plate from the concrete so you can eliminate the treated sill plate and use just a standard sill plate.
How difficult is it to install?
This installation has a very quick learning curve. Since there are 2 parts to the system, you will have to install them at 2 different times. The framers install the Vent, which comes in 3-foot sections, before they install the sill plate. Then a few weeks later when the siders are ready to install the exterior siding, the second part of the system is installed, the vent covering / flashing, which comes in 10-foot sections.
What are some of the differences and benefits of the Joto-Vent System vs the current concrete or rim joist vent boxes?
For the builder one of the biggest benefits is that the complete perimeter of the crawlspace is being vented instead of just the corners and every 8-10 feet of the foundation walls. This gives you a much better cross ventilation which leads to better moisture management in the crawlspace, thus prolonging the life of the wood under the house. For the engineer one of the biggest benefits is they no longer have to calculate the loss of strength in the foundation due to the vent box holes in the structural concrete or rim joists. As for the architect, the biggest benefit is the overall finished clean look of the exterior of the house with NO visible vent boxes. And for the homeowner, all of the above, plus the confidence that their crawlspace will be vented with the best ventilation system ever designed.
Many states have made changes to the building-code requirements for crawl-space ventilation and offer various exceptions. Are there any exceptions available in Washington State?
The International Building Code states that structures need 1 ft² of ventilation per 150 ft² of crawl space, or 1/150, but this ratio can be reduced to 1/1,500 where the ground surface is treated with an approved Class I vapor retarder. For those of us in Washington State, the Washington State Residential Code allows a 1/300 ratio as long as a ground cover of 6 mil (0.006 inch thick) black polyethylene or approved equal is laid over the ground within crawl spaces. The ground cover shall be overlapped 6 inches (152mm) minimum at the joints and shall extend to the foundation wall.