Crawl space venting?

[Brian A. MacNeish]

Originally Posted by cbuell

The IRC rquires venting or conditioning of the space. Conditioned doesn't mean that it has to be mechanically "vented"----it needs to "communicate" with the conditioned space. This communication can be passive or part of the forced air heating system. This may not always be essential----but it is still a good idea in most cases (at least according to the IRC Gods)

They are not the researchers or industry innovators and if they are regular 35-40 hr per week folks and do not have a passion for their work, they are behind the curve on some fast moving new items.

For example: I was installing Heat Recovery Ventilators in 1981; the codes adopted them as 1 of 6 options to meet ventilation requirements in 1995. It's 2007 and just about every newer house (even up to $1.5 million) that I inspect or consult on has items not meeting the ventilation codes.

When I go to Home depot or its competitors and view their "Walls of Fan Shame", only about 1 or 2 out of 10 fans offered meet our codes!!! Its up to the informed to make changes based on the research or innovation that hasn't reached the AHJ yet.

Oh! The 1.5 million house was an 11 month warranty inspection. It had

(1) 5 bath fans that did not meet code; 1 was already dead!!
(2) an HRV that the contractor lied about being balanced and signed his name to a label on the unit. It showed perfectly balanced at 274 cfm. I used to install that same unit 20 years ago and knew that it would not move that much air against the shrunken duct system I was seeing. So I cleaned the filters and outdoor hoods, inserted my flow measuring collar and found the unit moving about 135 cfm in high speed!!
(3) the groundwater source heat pump was cutting out on cold nights and going onto 100% electric heat. Upon checking things (an old business acquaintance is the manufacturer- Maritime Geothermal), it was found it needed another 4-6 gallons/min.
(4) A ductless A/C for 3 bonus rooms over the garage that (a) would not drain condensate properly, (b) had 2 of the room controls crosswired and (c) the outdoor condensing unit was just about to fall off the wall stand....they just used sheet metal screws to fasten it to the horizontal brackets- out of 8 or so installed, only two remained intact....was a good thing the owners were not using the system due to the other problems
(5) damaged shingles installed on the roof
(6) wine cellar leaked every rain plus a couple other smaller leaks
(7) not enough insulation in the attic
( A main load carrying parallel strand lumber (PSL) beam with a support post pushing about 3/8" into bottom of beam. They already had a good set of plans from a well known national manufacturer but chose a second set from a local firm that removed a main beam and put more load onto the above mentioned beam!!

Rant! Rant! Rant! You can screw up a lot of things on a $1.5 million house!!!

and it goes on and on!

[rwand1]

I love it when we disagree. I am for not venting crawlspaces based on my years of inspecting and finding vented crawlspaces are more troublesome than ones which are not vented, plastic vapour barrier, insulated and supplied with heat duct, or open into the basement.

[William M. Corbett]

IRC states 1 sf / 150 sf. If your crawl space si 100 sf; then you need a vent sized no less tha .667 sf. JMO

[Peter C. Russell]

The building inspector called me this AM and said I'm all set, no vents OK even though the state of NH goes by the 2006 IRC.

Like I said before every town can adopt what they want. I'm just glad I don't have to cut a vent into that foundation.

[Roy D. Cooke, Sr]

Thanks Peter Been fun... Cookie

[Mario A. Kyriacou, CHI]

Originally Posted by prussell

Can anyone tell me if a crawl space with a concrete slab that is under 100 sqr. feet need venting.

I looked in the code book and it says 1 sqr. foot per 150 sqr. feet.

Peter

Our Ontario Building Code has the same requirement. Wheather we believe in venting crawl spaces or not the building code states that we should.

[rwand1]

I believe the code is minimum and regional Chief Building Officials have the power to alter or ammend the provisions as they see fit or for other benefit as long as it does not endanger or create another concern. In this case I think the research supports the issue that vents create more problems than they alleviate.

Is that your take Marcel?

Cheers,

[Marcel R. Cyr]

Originally Posted by rwand1

I believe the code is minimum and regional Chief Building Officials have the power to alter or ammend the provisions as they see fit or for other benefit as long as it does not endanger or create another concern. In this case I think the research supports the issue that vents create more problems than they alleviate.

Is that your take Marcel?

Cheers,

If all the properties involved with crawl spaces were to be designed and built as it should for the colder climates, yes I would agree that providing vents in the crawl space could be detrimental to the conditions of the under floor structure and the occupants of the dwelling.
It does not relinquish the fact that vents are required by the IRC and the Authority having Jurisdiction in a particular area has the last word, and may dictate what is acceptable or not based on the local Code adoptions.

How do we change the Code to reflect the Science of the Crawlspace? That is a good question, and until the parameters of the Crawlspace design is approved by the I-Codes and reflect the change, I guess we will have to keep writing it up when we inspect an un-vented Crawl.

On new construction, one could request a clairification from the AHJ based on the submitted design criteria and science back-up of the contrary.

Marcel

[Greg Veal]

I personally think that the next five - ten years will tell if ICC made the correct choice in redefining the insulation or ventilation of Attic areas and earthen crawl space areas. I look at the changes from a thermal, infiltration, as well as an infestation/conditions conducive perspective. I/We, in my climate zone answer not only the State/Local AHJ, but also the EPA local representative (our State Dept. of Agriculture). The rules are similar in most cases, but in some cases in direct conflict with each other. Trying to keep up to date with changes day to day and year to year can be confusing.

At least in the northern border states, you don't have to deal with ST and/or most WDO concerns we do down here. You have problems we don't have I'm sure, but...

[rwand1]

Actually....,

We have active colonies of Termites in Toronto, and some outlaying communities. The cold winters haven't seem to deter their advance northwards.

Cheers,

[Greg Veal]

It's funny, I was just having a conversation with one of the chief entomologist about just that, during some recent recertification training to maintain my licensing here in Ga.
He said that the subterranean termite was more active than we might think, given the conditions north of the border. Still nothing like us here, but migration and adaptability to your conditions has been amazing to him. He said he never thought that would be a concern...ever. Just goes to show that nowhere is safe from Gods little recyclers.

[Brian A. MacNeish]

Originally Posted by mkyriacou

Peter

Our Ontario Building Code has the same requirement. Wheather we believe in venting crawl spaces or not the building code states that we should.

Mario:

From the preface of the 2005 NBC (from which your OBC was probably developed) page ix:

DIVISION B: ACCEPTABLE SOLUTIONS

The term "requirements", which was used to describe the technical provisions contained in the 1995 NBC, has been replaced with the term "acceptable solutions" in the 2005 NBC. The change in terminology reflects the principle that building codes establish an acceptable level of risk and underlines the fact a code cannot describe all possible valid design and construction options.


The codes have always had a statement to allow for innovation and changes in building practices or else we'd still be building using pre-1941 (the year of the first NBC) techniques!! Talk to the codes people and present them with research they cannot dispute. I've helped 1 contractor and 1 owner/builder in the last 10-12 years get "supposed poor practice" through the inspection process.

[Roy D. Cooke, Sr]

Originally Posted by gveal

It's funny, I was just having a conversation with one of the chief entomologist about just that, during some recent recertification training to maintain my licensing here in Ga.
He said that the subterranean termite was more active than we might think, given the conditions north of the border. Still nothing like us here, but migration and adaptability to your conditions has been amazing to him. He said he never thought that would be a concern...ever. Just goes to show that nowhere is safe from Gods little recyclers.

They are now finding that with people in the City buying a cottage some tend to take there old Picknick tables and other wood from the city to the cottage and some are taking termites with this equipment.
They have also found that with no queen these termites can turn a worker into a queen and so new colonies are springing up in other places.
... Cookie.

[asargisian]

the code under in the IRC for the venting. R 408.1 and R-408.2

[asargisian]

IRC 2006 CODE # R-408.1 and also R408-2