Crawl space waterproofing

[Proactive]

Then it's a code violation, without being part of the conditioned envelope it reverts to the code mandated ventilation requirement of 1/150th of the floor area, check the link above or R-409.5.

I built a home in the early 80's using the Plenwood Heating System. Basically, the downdraft furnace blew warmed air directly into the crawl space; the crawl space perimeter was insulated and heat registers were cut into the subfloor in each room, wherever you wanted to put one. There was no ducting at all; the crawl space was used as one giant duct. Back then were were using All-Weather Wood Foundations as well. The main purpose of these "innovations" was to cut construction costs. Which they did, to a degree.

A year or so later we learned all about radon and how our area has one of the highest levels in the country.

Needless to say the Plenwood system wasn't too popular after that.

 

[Mr Rex]

Then it's a code violation, without being part of the conditioned envelope it reverts to the code mandated ventilation requirement of 1/150th of the floor area, check the link above or R-409.5.

You didn't read all the sections.

 

[Cigar]

Proavtive:

What you did wasn't legal at the time, but in Idaho building codes are relatively new to enforcement, it is now legal to create a plenum under the entire crawl space, I just checked California's comparable code, as of January 1st we went on a 722 page revision of the IRC for one and two family residential structures, to my surprise California has the same language as the North Carolina language I cited above, but it's labeled R408.3. Your plenum would fall under under R408.3.2.3 in California .

We were told one of the main reasons we had to go on a simplified residential code was nationwide uniformity, now I see that the numbers aren't even the same, I've got a lot to learn with this new code after spending 50 years learning the ever evolving UBC, then 3 years on the IBC, and now the IRC.

 

[Cigar]

You didn't read all the sections.

Yes I did, if sealed it has to have:
1) Continuous mechanical ventilation.
or
2) Conditioned air.
or
3) Be a Plenum complaint with the mechanical code such as Proactive has.

 

[Mr Rex]

The first option is a dehumdifier. 2nd is a supply with no return. 3rd is supply from the house by separate fan with no return. 4th is an exhaust fan. 5th is an option for "conditioning" the space. From all the literature I have read and seminars I have attended regarding these systems, conditioning the crawlspace is the least desirous for obvious reasons.

FWIW, I was at a seminar at NC State several years back when these systems were first being tested and before code acceptance put on by the folks that did the research. The NC DOI Code enforcement folks etc were also there. The results are the link I posted.

 

[Proactive]

Proactive:

What you did wasn't legal at the time, but in Idaho building codes are relatively new to enforcement...

Yep, legal, inspected and approved by a citified building inspector under the UBC. Of course back then, we still had wooden sidewalks, dirt streets and outhouses...

It IS Idaho, after all.

 

[Cigar]

Mr. Rex:

Apparently every state is handling it differently, so I guess the OP has to go to the Michigan version of the IRC, and see which, if any, of the ventilation requirements were complied with, since the owner is having problems already probably none of the ventilation requirements were complied with.

She states that the humidity is increasing and she is concerned about what will happen if she tries to refi with FHA.

I told her I would note the "upgrades", and the lack of venting, plus include photos and let the underwriter deal with it.

With increased humidity come dryrot and termites (if Michigan has termites).

hglenbetts:

Since the client is a friend, perhaps you should tell her to get the installer of this new system back and install ventilation under permit to code.

 

[Mr Rex]

A dehumdifier in the crawlspace is a simple solution, and the most energy efficient option IMHO.

 

[hglenbetts]

Interesting discussion. Thanks all.

@Cigar, that is essentially the course of action she is planning on. Thanx.

BUT... Bottom line... Who would actually call for the "re"installation of venting in their report?? Rather than just state what was observed.. after all 4150.2 states Crawl Space....."must be properly vented".

 

[Mr Rex]

If your state allows "sealed crawlspaces" then it may be properly vented with a de-humidifier and or other means allowed by code. Alot of the FHA protocol was written last century