Do your exhaust vents terminate at your soffits?

The building codes specify that exhaust fans shall not terminate in the attic or soffits. While there are those that argue “at the soffits” is not the same as “through the soffits,” I think it pretty much amounts to the same thing.

The reasons we do not want to vent warm moist air into attics is well known and documented. It can lead to mold growth and other four letter words.

So what exactly does the code say:

M1501.1 Outdoor discharge. Air shall not be exhausted into an attic, soffit, ridge vent or crawl space.

That seems straightforward enough, and since “aimed at the soffit” is still in the attic, my personal opinion is, when the code says “Shall not be exhausted into a …..soffit,” they are meaning “through the soffit” as well.

So let’s forget about the code, and let’s see if my opinion can be supported by building science.

Wow, do we really have to go to “science?”

What are the building conditions that would come into play to sort this all out? Typically, or at least most of the time, in a properly vented attic, the attic space is under negative pressure relative to the higher pressures at the soffits and at the ridge. Because of this, air is attempting to push its way into the negative air space to make balance–24/7. All air in the vicinity of the soffit vents is forcing its way into the vents.

Now lets place a bathroom exhaust fan vent right at the soffit vents.

We are exhausting warm, wet, buoyant air that it is already moving upward and increasing the pressure in the area of the soffits. This increase in pressure difference between the attic space and the soffits makes that warm wet air work even harder to get into the attic.

In this picture, you can see evidence of where corrections have been made of the four vents that terminated too close to the soffit. The opening have been covered over, and hopefully they now terminate properly through the roof.

The staining on the siding above the lower vents is consistent with the buoyancy of the air from the vents.

Staining above the soffit vents on the underside of the roof sheathing is consistent with the upper vent’s previous termination at the soffits.

I think the codes need to clean this up a bit and require minimum distances to vented soffits.  Any current guidelines are at best “vague.”

Until then we should resort to good sense.

Charles Buell, Real Estate Inspections in Seattle

 

New study finds that water runs down hill! Who knew?

Today is a day that will live in infamy as the discovery that water runs down hill was announced by a previously unknown kindergarten teacher in Seattle, Washington (obviously not the other Washington).

The teacher’s class of kindergartners, using standard garden hoses, Odwalla fruit juices and hamster slides, showed beyond a reasonable doubt that water does in fact run down hill. Before this day, this fact was obviously not known.

Because of how recent this discovery is, it is projected that there are still thousands of builders constructing homes unaware of the new information.

Many builders have expressed surprise at the way gravity affects water. Some even reacted with denial and accusations. Many were heard to say that the kindergartners, “don’t know what they are talking about—obviously!” Others remarked at how this information will be costly in the building of new homes from here on out.

Others called for further studies prior to jumping to rash conclusions.

Still others argued that government meddling in a free economy was likely involved. After all why shouldn’t someone be able to build a house any way they want regardless of what water does or does not do?

The very notion that flashings would now be required over any trim boards that are nailed on top of siding, above windows and doors, seemed just preposterous. But the fact that water was now known to be affected by gravity seemed difficult to reconcile with the industry standard of not installing any flashings at all. Is it any wonder that builders everywhere are crying foul?

Head flashing is missing

Head flashing is missing

Some builders, when shown pictures of the problem, merely argued for more caulk–although that did not seem to impress the kindergartners very much.

And caulking won't be good either

And caulking won’t be good either

It remains to be seen how this new information will affect home construction. Many experts belief that the information will be ignored and standard building practice will not be affected at all.

Only time will tell

By Charles Buell, Real Estate Inspections in Seattle

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Walkways and Bridges

While we all would love to have a moat around our castle, the walkways to today’s castles generally don’t have to be too concerned with how well they can deter invading marauders or emissaries from Game of Thrones.

If today’s castles can keep out an occasional crusading evangelist, political campaigner or vacuum cleaner salesman, that is all we can hope for.

I am sure some designer or architect spent considerable time designing the bridge to the front entryway of this castle–crossing over the carefully rock-lined artificial stream.

The Castle Road

But really…..is this acceptable for night time visitors to the home? How about a hoard of little trick-or-treaters? How easy would it be to take an inadvertent swim with the alligators from one slight miss-step?

I don’t even want to think about wheel chairs.

This might be a good example of the codes being a “minimum” standard. In the days of castles there might be armored guards to throw you in the moat. While not required by today’s standards, a barrier/guard would certainly be prudent on the path to this castle—or having a very good insurance policy.

Some designs are simply a lawsuit away from becoming the latest code change.

Charles Buell, Real Estate Inspections in Seattle